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  1. #1
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    Four-bar vs Faux-bar

    I recently read an article in a British MTB mag about different types of full suspension. They break full suspensions into 5 groups:

    1. Single pivot - Orange
    2. Four-bar - Horst link on chainstay, isolating suspension from pedalling / braking
    3. Faux-bar - Pivot is above dropouts on the seatstay, behave like single pivot bikes.
    The linkages are there to help drive the shock.
    4. VPP - Blur, Spider
    5. Floating drivetrain - GT i-drive, Maverick

    I had not previously encountered the term "faux-bar suspension". I was wondering if any of the suspension gurus on mtbr could elaborate on the differences between four-bar and faux-bar suspensions. Thanks.
    Kokopelli Racing

    "Curb drops to flat, or curb drops to transition? There's a BIG difference there." Qfactor03

  2. #2
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    Axle on a floating link vs swingarm

    Quote Originally Posted by yangpei
    I recently read an article in a British MTB mag about different types of full suspension. They break full suspensions into 5 groups:

    1. Single pivot - Orange
    2. Four-bar - Horst link on chainstay, isolating suspension from pedalling / braking
    3. Faux-bar - Pivot is above dropouts on the seatstay, behave like single pivot bikes.
    The linkages are there to help drive the shock.
    4. VPP - Blur, Spider
    5. Floating drivetrain - GT i-drive, Maverick

    I had not previously encountered the term "faux-bar suspension". I was wondering if any of the suspension gurus on mtbr could elaborate on the differences between four-bar and faux-bar suspensions. Thanks.
    Do a text search in mtbr. There are many uses of faux-bar discussions.

    So called Faux-bar has a physical monopivot swingarm determining the path of the axle to the frame. Four-bars have 2 swing arms from the frame connected to a "floating" link and the axle's path to the frame is determined by the paths of all the links not just one swing link.

    VPP's are also 4-bars but with very short swing links between the frame and floating link (or floating rear triangle).

    With floating axle 4-bars the rates of path curve and associated force tensions are sometimes tuned to be non-circular when using shorter swinglinks, such as the VPP's slightly "s" shaped path, while all monopivot swingarms have a circular paths with the frame.

    Your really must ride various designs to get a good sense of the subtle differences.

    - ray

  3. #3
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    The suspension "gurus" certainly can "elaborate" and have done so on countless threads in the past. The hardest part is wading through all the b*lls*it to actually learn anything useful.

  4. #4
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    Quote Originally Posted by uktrailmonster
    The suspension "gurus" certainly can "elaborate" and have done so on countless threads in the past. The hardest part is wading through all the b*lls*it to actually learn anything useful.
    well said......

    also be aware that many of these arguments will be based on theoretical arguments which while they may hold at that level, do not translate into a practical difference that will matter to you.

    also note that there are MANY parameters to how well a bike will ride for you, not just type of linkage. As I have said before, I could try to make a horst link bike and it would be a POS because the implementation would be the worst......would that imply that a horst linkage is not a good one?

    the ride of a bike is a multivariate equation if you will.....with many variable perhaps independently important, but when added to the equation along with the other important variables, may not matter so much and will often have interaction effects that become important..

    bottom line.....in my simple mind, if the implementations is solid based on virtually any common linkage, it can be a killer bike with its own pluses and minuses, subtle or otherwise.

    cheers

  5. #5
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    Why not a FAQ?

    I seriously think it's time to get a few FAQ threads on the topic! (e.g. one for Wheel path, and one for Shock linkages.)

    Also there's URT (unified rear triangle not common any more), Giant Maestro, DW-link, and Marin (whyte) linkages. Can't think of any others at the moment.

  6. #6
    Jm.
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    "Faux bar" is a faux term created by specializeds marketing department to make their suspension seem superior to anything else.

    A suspension system is either 4 bar or not, in other words it either has 4 components (linkage, main frame and two actuating rods (usually chainstay and seatstay) or it does not. It's just describing the parts. Pretty much any bike with a linkage is a 4-bar bike, becuase to make a linkage work you need 4 comoponents, hence the name 4-bar.

    A kona linkage-actuated single pivot is a 4 bar because there is the main frame, a chainstay, a seatstay (that actuates the linkage) and a linkage.

    A moto link bike like the Giant DH bike and Rocky Mountain RM series is 4 bar because there's the main frame, the swingarm, a pushrod, and a linkage. 4 parts.

    A horst link bike like a specialized is a 4 bar because there is a main frame, a chainstay, a seatstay driving the linkage, and a linkage.

    A VPP bike is a 4 bar because there is a main frame that constitutes one part, a rear triangle that constitutes another part, and two linkages, one of which drives the shock. Again, 4 parts.

    "Faux bar" is just a marketing term.
    I know in my heart that Ellsworth bikes are more durable by as much as double. AND they are all lighter...Tony Ellsworth

  7. #7
    The Ancient One
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    Quote Originally Posted by Jm.
    "Faux bar" is a faux term created by specializeds marketing department to make their suspension seem superior to anything else.

    A suspension system is either 4 bar or not, in other words it either has 4 components (linkage, main frame and two actuating rods (usually chainstay and seatstay) or it does not. It's just describing the parts. Pretty much any bike with a linkage is a 4-bar bike, becuase to make a linkage work you need 4 comoponents, hence the name 4-bar.

    A kona linkage-actuated single pivot is a 4 bar because there is the main frame, a chainstay, a seatstay (that actuates the linkage) and a linkage.

    A moto link bike like the Giant DH bike and Rocky Mountain RM series is 4 bar because there's the main frame, the swingarm, a pushrod, and a linkage. 4 parts.

    A horst link bike like a specialized is a 4 bar because there is a main frame, a chainstay, a seatstay driving the linkage, and a linkage.

    A VPP bike is a 4 bar because there is a main frame that constitutes one part, a rear triangle that constitutes another part, and two linkages, one of which drives the shock. Again, 4 parts.

    "Faux bar" is just a marketing term.
    I like "faux bar" because it's simple and mildly amusing. Otherwise you have to say "shock activating linkage" or "seat stay pivot linkage" as opposed to "chain stay pivot linkage" or "floating axle linkage" or some such.

  8. #8
    Jm.
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    Quote Originally Posted by Steve from JH
    I like "faux bar" because it's simple and mildly amusing.
    Well, I guess it's amusing, but I think of it like this;

    4-bar;
    Horst Link
    Single pivot
    Lawill
    VPP
    DW Link
    All other crap like Karpiel, Fulcrum, etc

    Monoshock;
    All designs like superlight, bullit, etc

    Other;
    Maverick and other stuff that does not easily go into one of the above catagories

    If you just want to make it easy on yourself, just call the Kona a single pivot 4-bar. It's simple, easy to understand, and doesn't use any wierd terms...
    I know in my heart that Ellsworth bikes are more durable by as much as double. AND they are all lighter...Tony Ellsworth

  9. #9
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    Best way to keep it simple:

    Ride a hard tail. I'm only half joking. I've been trying to convince myself to go FS for two years now, but everytime I get done with a test ride and jump from the FS back on to my HT and do the same loop, trail, or whatever, it always feels so much lighter and quicker that I end up deciding to keep the HT. Then, invariably, I get the bug again, decide I really want bike "X," "Y," or "Z" and start the process over again, always ending up disappointed with the test ride... Maybe if I threw my custom lightweight wheelset on the FS it would take care of the sluggishness (?). I really feel like I'm missing the boat or something, but when I compare them side by side, how can I argue with the evidence? BTW, I'm not talking about comparing to "lead sled" FS's either--the last one was a Racer-X 100 (although it had like 2.3 Kendas with tubes and a lot heavier components than I usually run...). I've decided I better wait until I can afford two bikes: my HT for most of what I ride and a 5" travel FS for the occasional shuttle ride (I'll be saving for a while...).

  10. #10
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    Faux-Bars are not Four-Bars

    Quote Originally Posted by Jm.
    "Faux bar" is a faux term created by specializeds marketing department to make their suspension seem superior to anything else.

    A suspension system is either 4 bar or not, in other words it either has 4 components (linkage, main frame and two actuating rods (usually chainstay and seatstay) or it does not. It's just describing the parts. Pretty much any bike with a linkage is a 4-bar bike, becuase to make a linkage work you need 4 comoponents, hence the name 4-bar.

    "Faux bar" is just a marketing term.
    Faux-Bars are not Four-Bars (and the term Faux-Bar is not just a marketing term). However, the bicycle community in general (marketing literature, magazines, web discussions, etc.) often uses the term "4 Bar" or "4 Bar Suspension" <I>incorrectly</I> to refer to any bicycle that uses a 4-bar linkage arrangement in the rear suspension (the Kona Dawg and Giant VT are examples of this incorrect usage). This leads to lots of confusion about this subject.

    Most of the people who take this stance will argue (as you have here) that since a Faux-Bar uses a four bar linkage it is a Four-Bar. This argument is absolutely incorrect (or at least it does not match the definition that has been in use for decades outside the mountain biking community). Whether or not a bike has a 4-bar linkage is not relevant, because those 4-bars (i.e. the 4 bars that make up the 4-bar linkage) are not the 4-bars we are talking about when we are talking about a 4-bar suspension.

    Those with a technical background (engineers in particular) seem to make this argument a lot. Maybe it's because most engineers instantly recognize that the seat tube, chainstay, seatstay, and rocker arms form a 4-bar linkage, and perhaps then they have <I>erroneously</I> deduced for themselves that that is why these bikes are called 4-bars. Although this argument does seem logical, it is simply not correct. The term <I>Four Bar Suspension</I> (or 4-bar for short) is well defined and has been used for decades outside the realm of mountain biking (in the automotive community for example) to describe a particular, well defined suspension configuration (defined long before the term was used to describe a bicycle suspension). A Faux-Bar suspension does not fit this definition, and therefore <I>by definition</I> is not a Four-Bar.

    Here are a couple of definitions:

    <B>Four Link Suspension:</B> A suspension system in which the axle housing (axle carrier) is connected to the chassis via <I>4 adjustable links</I>. By adjusting the position and/or lengths of these <I>4 adjustable links</I> you can adjust the location of the instant center (IC) of the rear axle.

    Being able to adjust the location of the IC can be an advantage for many reasons. For example, on a drag racing car the location of the IC determines how much weight is transferred to the rear tires during launch, so by adjusting the connection points and/or lengths of these <I>4 adjustable links</I>, you can control how much traction you have during launch. It is these <I>4 adjustable links</I> that we are talking about when we are talking about a Four-Link Suspension. Here is a picture of a Four-Link Suspension with the 4-links identified. You can see the various different mounting points for adjusting these <I>4 adjustable links</I>. Note that these 4 links in and of themselves do not form a 4-bar linkage and note also that these 4-links do not correspond to the 4 bars that you have identified.

    <img src="http://gallery.consumerreview.com/webcrossing/images/4-link.jpg">
    .
    .

    <B>Four Bar Suspension:</B> A Four-Bar Suspension is equivalent to a Four Link Suspension, except that the <I>4 links</I> are not adjustable (i.e. the location of the IC is fixed at design time).

    Most bicycle suspensions fall into the 4 bar category instead of the 4 link category because the <I>4 links</I> (bars) are typically not adjustable. Here is a picture of a <I>Four-Bar Suspension</I> with the 4-bars identified. Note that these 4 bars <I>do not</I> form a 4-bar linkage and note also that these 4-bars <I>do not</I> correspond to the 4-bars that you have identified.

    <img src="http://gallery.consumerreview.com/webcrossing/images/4-bar(2).jpg">
    .
    .
    For the skeptics out there (and to show that I have not invented this definition myself), here are a few web links that include the definition of a 4 link suspension (and a 3 link suspension - more on that later):

    http://www.olywa.net/rdsrfr/Air%20Li...t is a 4-link?
    http://www.mattsoldcars.com/techinfo/dictionary.shtml
    http://www.autoglossary.com/term_4.html
    http://www.off-road.com/prerocker/glossary.html
    .
    .

    Here is a picture of a typical Horst Link style Four-Bar. I have identified the 4 bars in the picture. Note that these 4-bars <I>do</I> correspond to the 4 bars in both pictures above, but that these 4-bars <I>do not</I> form a 4-bar linkage and that these 4-bars <I>do not</I> correspond to the 4-bars that you have identified. This bike is a Four-Bar.*

    <img src="http://gallery.consumerreview.com/webcrossing/images/horst.jpg">
    .
    .

    The "4 Bars" we are talking about are the <I>4 bars</I> that isolate the axle from the chassis. A Faux-Bar suspension does not have these 4 bars at all. This is why a Faux-Bar <I>by definition</I> is not a Four-Bar. In other words, on a Faux-Bar the axle carrier (in this case the chainstay assembly) is not isolated from the chassis by 4 Bars. Instead, the axle carrier is connected directly to the chassis (similar to a Ladder Bar suspension). It's commonly called a Faux-Bar because it looks like a Four-Bar even though it's not.

    <img src="http://gallery.consumerreview.com/webcrossing/images/faux-bar.jpg">
    .
    .

    I suppose you could argue that the mountain bike community has <I>redefined</I> the term "4-bar" to refer to any bicycle that uses a 4-bar linkage arrangement as a rear suspension system. Well, fair enough, but by this definition a hardtail with a Thudbuster seatpost would be a "4-bar". Is that really how you want to define the term "4-bar"? I would argue that common misuse of a term does not change the true definition of the term, especially when that term already has a well established definition. I also question the logic and reasoning behind redefining a term than has been used differently for decades.

    I like the term "Faux-Bar", because it draws a distinction between single pivot bikes that use a linkage to drive the shock and true four-bar designs. However, since there are many different types of four-bar bikes on the market (Horst, ICT, VPP, DW-Link, etc.) I think the term "Four-Bar" is much too vague and does lead to confusion because it is not used consistently (and the 3-bar discussion below makes it even more confusing). For these reasons, I guess I prefer to avoid using the term "Four-Bar" entirely, and try to use the terms Chainstay Pivot, Seatstay Pivot, VPP, DW-Link, etc. instead.
    .
    .

    * This is for the (observant) nitpickers that may have noticed that the chainstay assembly on the XCE shown above is physically not 2 links, rather it is 1 physical link. Does this make the XCE a "3 Bar" then? The answer is yes, technically it does (at least by the automotive definition). This is a common suspension configuration in the automotive community as well, where the upper (or lower) two links are combined into one link, forming a 3-Bar (or 3-Link) suspension. However, it is conceptually and functionally equivalent to a 4-bar.

    <img src="http://gallery.consumerreview.com/webcrossing/images/3-bar_01(2).jpg">

    I hesitate to mention this here, because I think it may just confuse the issue. However, I think the fact that the name "3-Link Suspension" has nothing to do with a 3-bar linkage (it doesn't use 3-bar linkage at all) helps to illustrate the fact that the name "4-Bar Suspension" has nothing to do with whether or not it uses a 4-bar linkage (even though, coincidentally, 4-bar suspensions do use a 4-bar linkage).

    http://www.ffcobra.com/FAQ/3link.html
    http://www.auto-ware.com/shoptalk/3_4_lk.htm


    Apparently, not everyone in the mountain bike community is confused about this. Here is a "3-Bar Suspension" bicycle:

    <img src="http://gallery.consumerreview.com/webcrossing/images/3-bar.jpg">
    .
    .

    To answer the original question. Four-Bar bikes and Faux-Bar bikes are visually very similar (well, at least Chainstay Pivot Four-Bar bikes are visibly similar to Faux-Bar bikes). However, conceptually they are very different. Conceptually, a Faux-Bar is a single pivot with a linkage that drives the shock. With a Faux-Bar, the IC (instantaneous center of rotation) and CC (center of curvature) of the rear axle are both fixed at the main pivot (as is the case with all single pivot bikes). With a Four-Bar suspension, the IC and CC can be placed anyplace in virtual space (thus the term VPP) and can move independently as the suspension cycles (the IC and CC don't even have to be physically located on the bike, and usually aren't).

    In regard to suspension design, there are many reasons that this may be an advantage. For example, the location of the IC has a large impact on how the bike behaves during braking. Being able to locate the IC anyplace in virtual space to help optimize braking performance is an advantage that Faux-Bar bikes do not have. However, that being said, in practice I think these differences are somewhat subtle and largely theoretical (at least when comparing chainstay pivot bikes and seatstay pivot bikes, I wouldn't necessarily say the same thing about other 4-bar bikes such as VPP, DW-Link, etc.). I have one of each (a Chainstay Pivot and a Seatstay Pivot), and I have yet to noticed any difference I could attribute to the location of the rear pivot (i.e. chainstay or seatstay). Then again, I don't charge into corners as hard and brake as aggressively as some do, so that may explain why I don't notice any difference (in other words, I'm not saying there isn't any difference, just that I don't notice any difference).
    Last edited by Backmarker; 01-04-2005 at 09:17 AM.

  11. #11
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    two bikes: my HT for most of what I ride and a 5~7" travel

    Quote Originally Posted by Chris2fur
    Ride a hard tail. I'm only half joking. I've been trying to convince myself to go FS for two years now, but everytime I get done with a test ride and jump from the FS back on to my HT and do the same loop, trail, or whatever, it always feels so much lighter and quicker that I end up deciding to keep the HT. Then, invariably, I get the bug again, decide I really want bike "X," "Y," or "Z" and start the process over again, always ending up disappointed with the test ride... Maybe if I threw my custom lightweight wheelset on the FS it would take care of the sluggishness (?). I really feel like I'm missing the boat or something, but when I compare them side by side, how can I argue with the evidence? BTW, I'm not talking about comparing to "lead sled" FS's either--the last one was a Racer-X 100 (although it had like 2.3 Kendas with tubes and a lot heavier components than I usually run...). I've decided I better wait until I can afford two bikes: my HT for most of what I ride and a 5" travel FS for the occasional shuttle ride (I'll be saving for a while...).
    know what you mean.
    HT for most of what I ride around in San Francisco Bay Area suits me well.
    If i lived around Lake Tahoe or Downieville I may want to expense of a good Turner coiled xs fs bike. I want a 6+" fs for the occasional shuttle rides or to check out DH races.

    for the price of one light xc fs disk bike $3000+ one could get one disk hardtail (Marin Pine Mountain steel $1300) and one fs disk (Kona Coiler $1600)

    me:
    I'll keep triming the weight off my steel hardtail without sacrificing performance & durability and buy the Coiler (or Stinky) when i'm ready.
    Last edited by TrailNut; 01-04-2005 at 01:25 PM.
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  12. #12
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    It's hard to believe that the geometry of that Turner and Rocky Mountain would be all that different since the only real difference is the location of one pivot (seat stay vs chain stay). Could it be argued that the chain stay is actually a better place for it since there's one less pivot to flex between the chassis and the axle? It's interesting to me that every successful off-road motorcycle design uses a single pivot instead of a 4-bar, and they're dealing with a LOT more torque and suspension loads than bicycles have to.

  13. #13
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    Different beasts...

    Quote Originally Posted by ElementRaceRider
    It's hard to believe that the geometry of that Turner and Rocky Mountain would be all that different since the only real difference is the location of one pivot (seat stay vs chain stay). Could it be argued that the chain stay is actually a better place for it since there's one less pivot to flex between the chassis and the axle? It's interesting to me that every successful off-road motorcycle design uses a single pivot instead of a 4-bar, and they're dealing with a LOT more torque and suspension loads than bicycles have to.
    Motorcycles have a heavy engine that delivers massive and continous amounts of torque. (and adds to a lower center of gravity) Bikes only have the rider, are scads lighter than motorcycles, and more importantly are driven by a very transient power stroke. In short a motorcycle only has to deal with bob once, when you hit the accelerator. A bike must fight bob with every pedal stroke.

    As for geometry, while tthe RM and the Turner have very similar apperances, slight differences in gometry can make a world of difference. Just drop you seat 2" or raise up you fork an inch, move you seat back an inch. It can change the ride dramatically depending on what you have and what you need. It's difficult to see the difference between a 73.5deg STA and a 71 deg STA , but you'll feel it the moment you try to climb something. Same with a HTA: 68.5 feels quite different than 70 but is only 1.5 degs different. The two angles (STA & HTA) together play a big role in defining the characteristis of a bike. So do pivot locations even in bikes of similar designs, move the main pivot just a little on a HL bike and it will feel like a different bike. Same goes for moving the HL, rocker angle, rocker length yatta.... Casual observation of a bike's layout gives very little information on how it will ride.

    As for lateral stiffness, pivot design and implementation has as much affect as linkage type. Turners are very stiff latterally because their pivots are designed to handle lateral loads very well. Even two bikes of similar linkage designs can be very different in stiffness if one does not implement the pivots well. Even if they both use the same kind of bearings.

    BTW, Backmarker, that's probably the most sensible, and practical clarification of 4-bar suspension I've seen, Thanks!
    Faster is better, even when it's not.

  14. #14
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    Backmarker, that's a hell of a long winded way of explaining the difference between a 4-bar and faux link!! I do agree though. The big question is whether or not a virtual pivot point on a bike is a wothwhile advantage over a fixed pivot. I very much doubt it but I may be wrong. Your point about dragsters changing their IC to adjust weight transfer to the rear axle is incorrect though. The suspension geometry only affects the amount of squat in the suspension and the dynamic camber and toe angles of the wheels. A lot of people intuitively mistake increased suspension movement (particularly squat) for increased weight transfer. Weight transfer occurs due to acceleration and the amount is governed simply by the location of the centre of gravity and the wheelbase. A high CofG and a short wheelbase are what you require for increased weight transfer.

  15. #15
    Neg reppers r my biatches
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    Wow.....

    By the way, what do you call 10,000 engineers at the bottom of the ocean

    Cheers

  16. #16
    not so super...
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    and to bring back another favorite
    Attached Images Attached Images
    Nothing to see here.

  17. #17
    Neg reppers r my biatches
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    Quote Originally Posted by SSINGA
    and to bring back another favorite
    very nice...I'll keep that one

  18. #18
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    Jm seems to miss the point between a four bar linkage and four bar suspension.

    A kona for example is a four bar linkage, but it ain't four bar suspension. It's a monopivot, so we call it a faux bar.

    The differences, in a general nutshell a four bar squats less under acceleration, climbing and braking than a faux bar. This makes them feel crisper under power, stay more level when climbing and accelerating and bob less when running an open shock.

    Four bars can also have some awful bad habits if the designer doesn't get it right (e.g. GT LTS).

    The VPP, DW link, new giants, schwinn rockets, are all four bars.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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  19. #19
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    I was about to point out the same thing to Backmarker about weight transfer, but you beat me to it.

    I think there are real but small efficiency advantages in the way a four bar rolls over bumps. The argument is complicated but depends on positioning the instant center significantly ahead of the center of mass. That's only possible with a 4 bar when talking about a bicycle.

    This energy efficiency advantage wouldn't matter in motorsports. And you probably can't feel it directly. Indirectly it should show up in reduced times over the same course from the same rider effort or less rider fatigue from the same time over the same course. But there are so many variables here that it would be damned hard to prove.

    The only company I know of that tried to prove it, among other things, is Devinci of Canada. They experimented for a couple of years I think with an instrumented bike and tried lots of different pivot designs. They ended up opting for something close to the Ellsworth 4 bar design and are in fact licensing ICT from Ellsworth. They switched the Banzai model, their "all mountain" bike, from a faux bar to the new design.

  20. #20
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    Backmarker, you're really Zag, aren't you? This must be at least your fourth name change.

  21. #21
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    Quote Originally Posted by Steve from JH
    I was about to point out the same thing to Backmarker about weight transfer, but you beat me to it.

    I think there are real but small efficiency advantages in the way a four bar rolls over bumps. The argument is complicated but depends on positioning the instant center significantly ahead of the center of mass. That's only possible with a 4 bar when talking about a bicycle.

    This energy efficiency advantage wouldn't matter in motorsports. And you probably can't feel it directly. Indirectly it should show up in reduced times over the same course from the same rider effort or less rider fatigue from the same time over the same course. But there are so many variables here that it would be damned hard to prove.

    The only company I know of that tried to prove it, among other things, is Devinci of Canada. They experimented for a couple of years I think with an instrumented bike and tried lots of different pivot designs. They ended up opting for something close to the Ellsworth 4 bar design and are in fact licensing ICT from Ellsworth. They switched the Banzai model, their "all mountain" bike, from a faux bar to the new design.
    You're right, it's not really relevant to motorsport. As you say, there are a lot of variables making any theoretical efficiency gain difficult to prove or at least quantify. Personally I ride a Ventana X5 (lowly faux bar - LOL) but find it a very efficient bike due to its class leading rear lateral stiffness and low bearing stiction. Drawing a parallel with motorsport again, torsional chassis stiffness and suspension installation stiffness are both key factors and are ultimately more important than subtle suspension geometry changes. I've heard that Ventana stayed with the faux bar because Sherwood was not convinced he could justify the loss of rear triangle stiffness with a chain stay pivot. I suspect he may have a valid point. In any case, the X5 is a great ride and the transfer of torque through the rear triangle feels very direct. This attribute has also been commented on in several reviews of the bike. Other supposedly more sophisticated bikes I've tried have disappointed me with notable rear end flexing.

  22. #22
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    Quote Originally Posted by Bikezilla
    Motorcycles have a heavy engine that delivers massive and continous amounts of torque. (and adds to a lower center of gravity) Bikes only have the rider, are scads lighter than motorcycles, and more importantly are driven by a very transient power stroke. In short a motorcycle only has to deal with bob once, when you hit the accelerator. A bike must fight bob with every pedal stroke.
    I understand about the bob but with a motor bike there's always torque being applied, not just during initial acceleration. Then it gets reversed while braking, just as it is on a bicycle. If one of the advantages of a 4-bar design is maintaining suspension performance while braking why haven't any motorcycle designers seen it? That's all I was wondering.

    FWIW, every full suspension bike I've ever ridden bobs up and down to some degree when I pedal it, even the old URT designs. Not from chain torque but from me pushing my legs down/torso up. How could a suspension know the difference from gravity induced motion (bumps) and rider induced motion (pedaling)?

  23. #23
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    Quote Originally Posted by SSINGA
    and to bring back another favorite
    Unless that pancake has a mouth, I think there's 2 pancakes on the bunny's head.
    James

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    Quote Originally Posted by Osokolo
    small minds usually try to insult other people by saying things that they themselves suffer from...
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  24. #24
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    Quote Originally Posted by ElementRaceRider
    I understand about the bob but with a motor bike there's always torque being applied, not just during initial acceleration. Then it gets reversed while braking, just as it is on a bicycle. If one of the advantages of a 4-bar design is maintaining suspension performance while braking why haven't any motorcycle designers seen it? That's all I was wondering.
    Motor bikes have all kinds of other things going on. Some actually have floating calipers, their shocks can be more sophisticated (up until recently anyway) there's a big whack of weight in the center of the bike that changes everything. Besides there are tons of different motor bike suspension designs, you'll have to be slightly more specific of which brand/design and application before saying it dosen't do what a bicycle does. I'm sure some do. Overall there is very little practical similarity between motorcycles and bicycles as far as suspension designs. The applications are very different.

    Quote Originally Posted by ElementRaceRider
    FWIW, every full suspension bike I've ever ridden bobs up and down to some degree when I pedal it, even the old URT designs. Not from chain torque but from me pushing my legs down/torso up. How could a suspension know the difference from gravity induced motion (bumps) and rider induced motion (pedaling)?
    Oh that's EASY! It can't, and it dosen't A good fully can dramatically reduce bob caused by pedal torque, but up and down body motion is still going to affect the suspension, there's no way to eliminate it uneless the suspension is partly locked out when the body downforce occurs. Some bikes like the VPPs create a stiffer suspension during pedal torque so you can stand and hammer and get less vertical mass induced bob. Some bikes have very good platform dampers that resist slow speed compression, which is just what body mass bob is. This can and does come at the expense of small bump and slow speed compliance. I've found the some shocks manage a very good partial workaroud by having speed sensitive damping which takes over if the bump compression exceeds a certain rate. Some take it a step further by having position sensitive damping as well so as it get further into the compression it increases damping to keep from blowing through the stroke even though it's very supple in the beginning. (In case you're wondering I'm thinking of the DHX here) I personally was very suprised to find how effective the DHX platform was even though it gave scant little up to small bump compliance.

    Now as for rider mass induced bob...well you might want to read some of Steve from JH's posts on the matter. He went through some interesting experiments to prove it does not have to effect efficiency, and may very well not.

    But I have to say a seatstay pivot bike does not have to lag behind a Horst link bike in the real world... Yetti and Ventana are clear examples. And a Horst link bike does not have to lag behind a seat stay pivot bike when it comes to lateral stiffness...Turner is a clear example of this. One does not have to be better than the other, it's all about how it's executed.
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  25. #25
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    The difference is small but real...

    A true 4-bar (Horst link...FSR, Turner) shines on the rough stuff when pedaling and braking. When climbing steep rough trails that require heavy pedal torque a Horst link's suspension does a better job at smoothing out the trail. It's the same with braking in the rough.

    Remember...it's still 95% rider.

    Mike

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    Quote Originally Posted by uktrailmonster
    ...Personally I ride a Ventana X5 (lowly faux bar - LOL) but find it a very efficient bike due to its class leading rear lateral stiffness and low bearing stiction. Drawing a parallel with motorsport again, torsional chassis stiffness and suspension installation stiffness are both key factors and are ultimately more important than subtle suspension geometry changes. I've heard that Ventana stayed with the faux bar because Sherwood was not convinced he could justify the loss of rear triangle stiffness with a chain stay pivot. I suspect he may have a valid point. In any case, the X5 is a great ride and the transfer of torque through the rear triangle feels very direct. This attribute has also been commented on in several reviews of the bike. Other supposedly more sophisticated bikes I've tried have disappointed me with notable rear end flexing.
    As I'm sure you know there's absolutely nothing lowly about a Ventana They are art on wheels.
    I think the efficiency has less to do with lateral stiffness, though. Any trailbike that flexses torrsionally under pedal power is pretty noodly in my book. I was under the impression that the lateral stiffness concerns are mostly for handling.

    IMO pivot stiction is almost totally a marketing consideration. The amount of force required to overcome any pivot stiction (bearing or bushing) is but a tiny fraction compared to the force created by the shock preload, the rider weight and especially the force created by a bump. A really good example of this is how many people never know their bearings are indexed and even totally shot until they take their shock off and cycle their suspension. Blown bearings can be felt by an loss in lateral stiffness but almost never felt in vertical motion.

    My thoughts on Lateral Stiffness of design: There have been several discussions on lateral stiffness of designs. The ones I read and participated in pretty much failed to convincingly prove how a SSP was inherently stiffer than a HL. I started to see some posibilities but in the end there are tons of examples where certain HLs are significantly stiffer than many SSP bikes, AND vice versa. IMO the Ventannas are latterally stiffer because it is Sherwood's priority, even if it compromised some pedaling and braking perfomance (ever so slightly...if at all) OTOH There are plenty of HLs that are stiffer than many very stiff SSP bikes...(excluding Ventanas I assume )

    It's all in the execution.
    Faster is better, even when it's not.

  27. #27
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    Quote Originally Posted by Steve from JH
    The only company I know of that tried to prove it, among other things, is Devinci of Canada. They experimented for a couple of years I think with an instrumented bike and tried lots of different pivot designs. They ended up opting for something close to the Ellsworth 4 bar design and are in fact licensing ICT from Ellsworth. They switched the Banzai model, their "all mountain" bike, from a faux bar to the new design.
    Curious, how come Devinci aren't able to sell the ICT bikes in the US, since ICT isn't an FSR? I heard it was due to patent infringement with Specializeds' Horst Link. Here's a thread about the 2005 Devinci FSR? issue. Very curious too hear more about the ICT thing.

    NSMB did a report on the Devinci 05 line and also mentioned the FSR, Link here. Here is a brief part of the report...
    Quote Originally Posted by NSMB
    Sharp-eyed readers will notice that the bikes on display here use a different rear linkage than those available north of the 49th parallel.

    Devinci bikes sold in Canada use the Horst Link four-bar rear suspension design, but because Specialized holds the U.S. patent on four-bar and is reluctant to license it to other companies, Devinci has to get creative and develop its own chainstay / seatstay pivot and dropout for bikes sold in that market.
    Don't get me wrong, I'm not saying your wrong. I'm just trying to clarify for myself if it has the Horst or ICT link. That's why I'm asking about your ICT info. Thanks.

  28. #28
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    Quote Originally Posted by red5
    Don't get me wrong, I'm not saying your wrong. I'm just trying to clarify for myself if it has the Horst or ICT link.
    As far as I'm concerned ICT is horst link.
    The patent lawyers may disagree, but that's what they're paid to do.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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    From what I recall, EW has a special agreement with Specalized. (as does Giant) That agreement does not instantly transfer to every ICT compliant bike. Da Vinci would have to cut their own deal with Specy. Besides, even though the Banzai is ICT compliant, that does not mean it does exactly all the ICT things an EW does...the same thing goes for Turner. They're still paying Specy for FSR rights even though EW made them wear the EW-ICT badge of shame.
    Faster is better, even when it's not.

  30. #30
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    Quote Originally Posted by Steve from JH
    Backmarker, you're really Zag, aren't you? This must be at least your fourth name change.
    Well, I've logging onto this site almost daily since 1997. During that span, off the top of my head, I can think of five. But who's counting right

  31. #31
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    Quote Originally Posted by Bikezilla
    As I'm sure you know there's absolutely nothing lowly about a Ventana They are art on wheels.
    I think the efficiency has less to do with lateral stiffness, though. Any trailbike that flexses torrsionally under pedal power is pretty noodly in my book. I was under the impression that the lateral stiffness concerns are mostly for handling.

    IMO pivot stiction is almost totally a marketing consideration. The amount of force required to overcome any pivot stiction (bearing or bushing) is but a tiny fraction compared to the force created by the shock preload, the rider weight and especially the force created by a bump. A really good example of this is how many people never know their bearings are indexed and even totally shot until they take their shock off and cycle their suspension. Blown bearings can be felt by an loss in lateral stiffness but almost never felt in vertical motion.

    My thoughts on Lateral Stiffness of design: There have been several discussions on lateral stiffness of designs. The ones I read and participated in pretty much failed to convincingly prove how a SSP was inherently stiffer than a HL. I started to see some posibilities but in the end there are tons of examples where certain HLs are significantly stiffer than many SSP bikes, AND vice versa. IMO the Ventannas are latterally stiffer because it is Sherwood's priority, even if it compromised some pedaling and braking perfomance (ever so slightly...if at all) OTOH There are plenty of HLs that are stiffer than many very stiff SSP bikes...(excluding Ventanas I assume )

    It's all in the execution.
    I agree totally. I should have said excellent lateral AND torsional stiffness when referring to the X5. I too was wondering how much stiffness you would actually lose with a chain stay pivot, all other things being equal. IMO Sherwood's design priorities are spot on, which is why I choose to own one!

    You may be right about the insignificance of pivot stiction in this application, but on racing cars stiction is more important than you may think. Shock designers certainly consider stiction an important factor when looking at seals and bushes etc. High stiction usually means you lose low speed sensitivity. I've seen this negative effect in both suspension bearing stiction and damper stiction. Suspension stiction was almost entirely removed in F1 with the introduction of flexure joints (which are not really suitable for long travel MTBs) and torsion bar springs.

  32. #32
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    Quote Originally Posted by uktrailmonster
    Backmarker, that's a hell of a long winded way of explaining the difference between a 4-bar and faux link!!
    Yeah, you are right, embarrassingly so. However, I have been arguing this point on this site going on 9 years now, and I have tried the simple approach such as:

    <I>"If the rear axle is mounted to any suspension member that is directly connected to the main frame, it is not a 4-bar"</I>

    That statement is concise and is 100% correct. However, every single time I end up in a discussion (argument?) with someone who is absolutely convinced that any bike that uses a 4-bar linkage is a 4-bar suspension bike. I have found it very difficult to find a concise argument that clearly illustrates why faux-bar bikes are not four-bars. In this case, I was trying to vividly illustrate the significance of the 4 "bars" that determine the location of the IC, and to show that these 4 "bars" are not present on a faux-bar suspension.
    .
    .


    Quote Originally Posted by uktrailmonster
    I do agree though. The big question is whether or not a virtual pivot point on a bike is a worthwhile advantage over a fixed pivot. I very much doubt it but I may be wrong.
    I agree to a point, but I think it depends on which designs you are comparing. If you are comparing a bike like a Turner XCE to a Ventana X5 (which have very similar effective main pivot locations), I think that if there is any difference, that is is very, very subtle. I'm not sure that the masses and accelerations that you are dealing with on a bicycle are large enough to make these differences noticeable. I have heard the XCE design described as a 4-bar that emulates a low mono-pivot with a floating brake, and I think that's pretty accurate. I also have a Rocky Mountain Element, and like I mentioned in my loooong post, I don't notice any differences that could be attributed to the rear pivot location. However, there are differences. For example, the suspension rate is very different (XCE is rising, and the Element is Falling) and this is very noticeable.

    However, the 4-bar design gives you so many more possibilities in regards to location of the IC and CC, that I wouldn't go so far as to say that a virtual pivot point is not a worthwhile advantage. There are some 4-bar designs out there that are doing some things that I am not sure would be possible with a single pivot (NRS, VPP, DW-Link, Marin Quad, etc.). I wouldn't say that any of these designs are better or worse than a single pivot, but I think they may be significantly different. Different enough to feel on the trail. I hope to find out for myself, because I will be adding a VPP bike to my stable, and I plan on doing lots of back to back to back testing with the seatstay pivot, chainstay pivot, and VPP bikes.
    .
    .

    Quote Originally Posted by uktrailmonster
    Your point about dragsters changing their IC to adjust weight transfer to the rear axle is incorrect though. The suspension geometry only affects the amount of squat in the suspension and the dynamic camber and toe angles of the wheels. A lot of people intuitively mistake increased suspension movement (particularly squat) for increased weight transfer. Weight transfer occurs due to acceleration and the amount is governed simply by the location of the centre of gravity and the wheelbase. A high CofG and a short wheelbase are what you require for increased weight transfer.
    Well, I included this statement because I was trying to find a fairly simple example that would illustrate why being able to adjust the location of the IC is significant. I come up with a different example each time, and each time someone (usually Steve) tells me I'm wrong. Perhaps I got it wrong again. However, I'm not sure that I did. I agree with you that the location of the IC affects the amount of squat (or rise) in the suspension. However, don't forget that when the suspension squats or rises the center of gravity moves as well (and the wheel base changes slightly). On a drag car, the center of gravity can move several inches up or down depending on the amount of rise or squat. In theory, this changing of the location of the center of gravity should change the amount of weight that is transferred to the rear tires. Also, the location of the IC affects how much traction you have. More traction means you can launch harder (greater acceleration) which should also mean more weight transfer. However, I could be missing something here. I guess I will try to think of another example.

    This is probably not new information for you, but others might find this link interesting. This link describes how the location of the IC affects the lauch of a drag car. However, the same basic principles apply to the location of the IC on a bicycle (i.e. for squat during climing, accelerating, braking, etc.):

    http://www.baselinesuspensions.com/i...A_Drag_Car.htm
    Last edited by Backmarker; 01-05-2005 at 04:50 AM.

  33. #33
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    Quote Originally Posted by Backmarker
    .
    Well, I included this statement because I was trying to find a fairly simple example that would illustrate why being able to adjust the location of the IC is significant. I come up with a different example each time, and each time someone (usually Steve) tells me I'm wrong. Perhaps I got it wrong again. However, I'm not sure that I did. I agree with you that the location of the IC affect the amount of squat (or rise) in the suspension. However, don't forget that when the suspension squats or rises the center of gravity moves as well (and the wheel base changes slightly). On a drag car, the center of gravity can move several inches up or down depending on the amount of rise or squat. In theory, this changing of the location of the center of gravity should change the amount of weight that is transferred to the rear tires. Also, the location of the IC affects how much traction you have. More traction means you can launch harder (greater acceleration) which should also mean more weight transfer. However, I could be missing something here. I guess I will try to think of another example.

    Here is an intersting link on how the location of the IC affects lauch:

    http://www.baselinesuspensions.com/i...A_Drag_Car.htm
    I agree with all your points. I almost mentioned that there is a small change in the CofG position, but the effect this has on overall weight transfer is very small if you do the maths. It's totally insignificant on all track racing cars, but may be worth considering on dragsters. The IC does affect traction because it determines the wheel path and the amount of anti-forces in the links etc. Of course you are also correct that increased accel means more weight transfer.

  34. #34
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    Quote Originally Posted by Jm.
    "Faux bar" is a faux term created by specializeds marketing department to make their suspension seem superior to anything else.

    A suspension system is either 4 bar or not, in other words it either has 4 components (linkage, main frame and two actuating rods (usually chainstay and seatstay) or it does not. It's just describing the parts. Pretty much any bike with a linkage is a 4-bar bike, becuase to make a linkage work you need 4 comoponents, hence the name 4-bar.

    "Faux bar" is just a marketing term.
    Don't forget the Rocky Mountain ETSX and the Mert Lawhil'sl designs (fisher, schwinn, and yeti variations), both are parallel link 4-bars, and the Balfa 2-step, and the old Azonic/World Force VR1 frame, and Bianchi and Wheeler and several other brands have done variations on that. There's a couple Mtn Cycles frame designs that like the Rocky RM series frames are four bars as well, having the swingarm, mainframe, linkage, and pushrod. Their Shockwave 9.5 for example.

    To drudge up another suspension definition from the old days, a mac-strut is a frame where the shock is rigidly attached to/serving as part of a stress bearing frame member (in the case of Amp B1 thru B4s for example, the shock was rigid with the seatstay which the wheel attached to). As such the Maverick ML7 frame design counts as a mac-strut (as did many older Offroad/Proflex/K2 models).
    I don't post to generate business for myself or make like I'm better than sliced bread

  35. #35
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    Quote Originally Posted by Backmarker
    Faux-Bars are not Four-Bars (and the term Faux-Bar is not just a marketing term). However, the bicycle community in general (marketing literature, magazines, web discussions, etc.) often uses the term "4 Bar" or "4 Bar Suspension" <I>incorrectly</I> to refer to any bicycle that uses a 4-bar linkage arrangement in the rear suspension (the Kona Dawg and Giant VT are examples of this incorrect usage). This leads to lots of confusion about this subject.
    SNIP

    That isn't new for the bike industry as ten years ago they redefined what a mac-strut was. If you're not used to it by now there's much hair pulling in your future.
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  36. #36
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    Lotus Super Seven Three Bar
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    Quote Originally Posted by ElementRaceRider
    It's hard to believe that the geometry of that Turner and Rocky Mountain would be all that different
    Are you talking about the geometry of the bike in general, or the geometry of the rear suspension (i.e. pivot locations, etc.)? I have a Rocky Mountain Element Race and a Turner XCE. If you are talking about the geometry of the bikes in general, these two bikes handle very differently. The handling difference is really night and day.
    .
    .


    Quote Originally Posted by ElementRaceRider
    since the only real difference is the location of one pivot (seat stay vs chain stay).
    Regarding suspension geometry, moving the rear pivot from the seatstay to the chainstay can change the location of the IC by several feet, so yes it can (at least theoretically) be significant. For example, the ICs on the Rocky Mountain Element and the Turner Flux are several feet apart. Think of it in terms of leverage. If you had a crow bar that was one foot long and you exchanged it for one that was 4 feet long, would you be able to notice the difference? Most likely you would. Moving the location of the IC changes the way forces are applied to the rear suspension. Moving it several feet may very well be noticeable (or it may not, depending on where you move it to).
    .
    .

    Quote Originally Posted by ElementRaceRider
    Could it be argued that the chain stay is actually a better place for it since there's one less pivot to flex between the chassis and the axle?
    Yes, of course it could, and it often is (it is generally agreed that the seatstay pivot design does result in a stiffer chassis, all other things being equal). Arguing that these two designs (faux-bar and four-bar) are different is not the same thing as arguing that one is better then the other. Of course, before we can even discuss the various advantages of each design, we have to agree that they are different.

    Also, remember that just because the 4-bar design gives you more options in regards to where the CC and IC can be placed, doesn't necessarily mean that these locations will result in "better" performance. You could easily design a 4-bar with CC and IC locations that would result in poor suspension performance. The simple truth is that the location of the CC and IC on a typical faux-bar (such as those from Rocky Mountain, Ventana, etc.) results in very good suspension performance.

    Besides, there really isn't such a thing as one design that is "better" for all applications. Design is about finding the set of tradeoffs that best matches the priorities of your specific application. The "best" design for one application may not be the "best" design for another.

    For example, take one guy who spends all of his time climbing really rough technical climbs while seated and then bombing down the other side. He may put a high priority on having the suspension remain fully active while pedaling. Take another guy who is looking for a full suspension bike for single speeding. Perhaps he spends a lot of time climbing out of the saddle up relatively smooth trails or fire roads and bombing down the other side. He may put a high priority on a firm pedaling platform and may be willing to trade off some suspension activity while pedaling. The "best "design for one of these applications may not be the "best" design for the other.
    .
    .

    Quote Originally Posted by ElementRaceRider
    It's interesting to me that every successful off-road motorcycle design uses a single pivot instead of a 4-bar, and they're dealing with a LOT more torque and suspension loads than bicycles have to.
    Motorcycles are a completely different beast (pedal feedback is a non-issue for example). Remember, design is about finding the set of tradeoffs that best meets the needs of your specific application. I don't know much about motocross racing, so I can't give any specific examples. However, it may be that braking performance is simply not as high a priority as are other things such as swingarm stiffness for example.

    Also, don't think that motorcycle suspension is not affected by chain tension. It is in a big way. I have ridden motorcycles and ATV's in which the suspension stiffened noticeably while under power. AMP Research makes a link for motorcycles and ATV's that addresses this problem and I can verify that it does work. I have ridden a Banshee with and without the AMP-Link and the rear suspension was noticeably more supple under power with the AMP-Link installed.

    http://www.amp-research.com/media/index.asp?cat=6

  38. #38
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    Quote Originally Posted by red5
    I'm just trying to clarify for myself if it has the Horst or ICT link.
    I agree with Dougal on this one. IMHO, ICT is a Horst link. I've read the Horst patent several times and I can't see where ICT would be excluded. However, I'm not a patent lawyer, so I may be overlooking some legal details. I would love to hear from a patent lawyer on this one.

    I tend to think of ICT as a subset of the Horst link design. The Horst patent describes the various suspension links and specifies where the various pivots must be located. The main pivot should be above the center of the bottom bracket preferably between the height of the small and large chainrings, the rear drop out pivot must be in-front of and below the rear axle, etc. ICT takes this a step further and narrows down the acceptable range of pivot locations to keep the chainline tracking the IC more closely than does the Horst patent. So, ICT is basically a subset of the Horst link design.

    One thing to consider, is that the original design for which the ICT patent was awarded (the Dare) doesn't appear to fall under the Horst patent, because the rear dropout pivot doesn't appear to be below the rear axle, at least not with a tall fork (which may explain why Ellsworth was awarded the patent in the first place). However, Ellsworth has since moved the rear pivot down and IMHO his current ICT designs do fall under the patent and should be licensed from Specialized. Again, that is just my uniformed opinion.

    I don't know how this would work for companies like Devinci that want to license the ICT design. Would they then have to pay the ICT license fee to Ellsworth and the Horst license fee to Specialized? Perhaps Ellsworth will try to force Specialized to put an ICT sticker on their bikes and we will all find out real quick .
    Last edited by Backmarker; 01-05-2005 at 09:33 AM.

  39. #39
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    I think EW and Specy convinced each other that they could sue each other until their pockets were empty and not get a clear resolution(Yes, I know EW dosen't have half Specy's bank), so they cut a deal. But I would imagine that deal would only extend to EW. So Davinci would have to make their own deal with both companies. I believe Specy cut a deal with Giant over the NRS as well.

    It seems however that EW managed to convince Turner that they (EW) were willing to spend more money fighting to prove the Turners were EW-ICT than it was practical for Turner to prove they were full of it. So now the Turners have both FSR and ICT tags on them...even though they are different, and Turner's HL is below the axle, and the designs were reached independently. (I'd like to think this is not the end of it though.)

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  40. #40
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    patent law question

    How did any of these guys get a patent?

    The concept of an isolated axle carrier has been around a
    long time as "Backmarker" has so eloquently illustrated.

    Whether it is a car or a bike it accomplishes the same thing.

    michael
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    Are you talking about the geometry of the bike in general, or the geometry of the rear suspension (i.e. pivot locations, etc.)? I have a Rocky Mountain Element Race and a Turner XCE. If you are talking about the geometry of the bikes in general, these two bikes handle very differently. The handling difference is really night and day.
    Geometry of the suspension. It's bizarre to a layman like me that moving a pivot a couple inches away to the chainstay would make such a huge difference in leverage, as you put it. Not doubting ya, just amazed by that.

    Since I (obviously) have the same bike, how would you describe the differences between your Element and the Turner?

    The Vanilla R on my bike blew it's damper so I was considering the Push platform damper upgrade instead of a simple overhaul from Fox. Is that a good match for the bike in your opinion?

  42. #42
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    Quote Originally Posted by mrdy
    Lotus Super Seven Three Bar
    The classic range rovers have three link rear suspension as well. The downside is the high roll centre can make for a very tail happy vehicle. Early on they solved that with a third spring (self levelling air spring) pushing down on the middle of the top link and quite soft (180 lb/in) coils on each side. Later on they added a sway bar to the front end to solve the oversteer.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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    OK, have read all the replies......wtf is a Fuel's rear sus considered (having rear triangle "flex" in place of a pivot point) ??? Am sure this has been asked before, so please bear with me....

  44. #44
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    Quote Originally Posted by Fuelish
    OK, have read all the replies......wtf is a Fuel's rear sus considered (having rear triangle "flex" in place of a pivot point) ??? Am sure this has been asked before, so please bear with me....
    The fuel is essentially a faux bar. the rear triangle flexes very little and mainly in the area of a chainstay pivot.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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  45. #45
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    I thought it was a seatstay pivot, no?
    BTW I think this helps illustrate how rear triangle pivots don't rotate much.
    Faster is better, even when it's not.

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    Just curious

    When did Specialized get the Horst Link patent?? There was no Specialized sticker on my retired LTS2. Also, how many out there think Specialized is a horse's arse for making everyone pay homage to them for using a Horst Link?

  47. #47
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    Just wanted to congratulate everybody...

    for finally having one 20+ post with any slander or name-calling.

    This is one of the best posts I've read the short time 4mths i've been on this site. And no, I'm not being facetious.
    James

    I aspire to be on Osokolo's ignore list.

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    small minds usually try to insult other people by saying things that they themselves suffer from...
    i dont care that you have a small penis or erectile disfunction

  48. #48
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    Quote Originally Posted by Bikezilla
    I thought it was a seatstay pivot, no?
    BTW I think this helps illustrate how rear triangle pivots don't rotate much.
    Yes you're right, it's a seatstay pivot. Sometimes my typing fingers don't listen and I'm not having much luck editing that post right now.

    Specialized has the patent because Horst Lietner designed some bikes for them in the early stages (early 90's). It wasn't until about 2000 that they started enforcing the patent which is well after LTS days.

    If you don't like it then sorry but that's how the world works. There'd be fewer good inventions if people and organisations couldn't protect their intellectual property.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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  49. #49
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    Quote Originally Posted by Dougal
    Specialized has the patent because Horst Lietner designed some bikes for them in the early stages (early 90's). It wasn't until about 2000 that they started enforcing the patent which is well after LTS days.

    If you don't like it then sorry but that's how the world works. There'd be fewer good inventions if people and organisations couldn't protect their intellectual property.
    Oh, didn't know that. It is not that I don't like, it just seems a bit heavy handed of Specialized to make other builders put a Specialized sticker on their bike. The other builders still have to pay a licensing fee, right? I mean, unless they get a discount on the fee if the put the sticker on, I don't know. Also, I just came back from perusing a couple LBS's and was indunated with Specialized bikes, or bikes with Specialized stickers. It just made me feel Microsofty all over.

  50. #50
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    My head hurts!

    Quote Originally Posted by Backmarker
    Faux-Bars are not Four-Bars (and the term Faux-Bar is not just a marketing term). However, the bicycle community in general (marketing literature, magazines, web discussions, etc.) often uses the term "4 Bar" or "4 Bar Suspension" <I>incorrectly</I> to refer to any bicycle that uses a 4-bar linkage arrangement in the rear suspension (the Kona Dawg and Giant VT are examples of this incorrect usage). This leads to lots of confusion about this subject.

    Most of the people who take this stance will argue (as you have here) that since a Faux-Bar uses a four bar linkage it is a Four-Bar. This argument is absolutely incorrect (or at least it does not match the definition that has been in use for decades outside the mountain biking community). Whether or not a bike has a 4-bar linkage is not relevant, because those 4-bars (i.e. the 4 bars that make up the 4-bar linkage) are not the 4-bars we are talking about when we are talking about a 4-bar suspension.

    Those with a technical background (engineers in particular) seem to make this argument a lot. Maybe it's because most engineers instantly recognize that the seat tube, chainstay, seatstay, and rocker arms form a 4-bar linkage, and perhaps then they have <I>erroneously</I> deduced for themselves that that is why these bikes are called 4-bars. Although this argument does seem logical, it is simply not correct. The term <I>Four Bar Suspension</I> (or 4-bar for short) is well defined and has been used for decades outside the realm of mountain biking (in the automotive community for example) to describe a particular, well defined suspension configuration (defined long before the term was used to describe a bicycle suspension). A Faux-Bar suspension does not fit this definition, and therefore <I>by definition</I> is not a Four-Bar.

    Here are a couple of definitions:

    <B>Four Link Suspension:</B> A suspension system in which the axle housing (axle carrier) is connected to the chassis via <I>4 adjustable links</I>. By adjusting the position and/or lengths of these <I>4 adjustable links</I> you can adjust the location of the instant center (IC) of the rear axle.

    Being able to adjust the location of the IC can be an advantage for many reasons. For example, on a drag racing car the location of the IC determines how much weight is transferred to the rear tires during launch, so by adjusting the connection points and/or lengths of these <I>4 adjustable links</I>, you can control how much traction you have during launch. It is these <I>4 adjustable links</I> that we are talking about when we are talking about a Four-Link Suspension. Here is a picture of a Four-Link Suspension with the 4-links identified. You can see the various different mounting points for adjusting these <I>4 adjustable links</I>. Note that these 4 links in and of themselves do not form a 4-bar linkage and note also that these 4-links do not correspond to the 4 bars that you have identified.

    <img src="http://gallery.consumerreview.com/webcrossing/images/4-link.jpg">
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    <B>Four Bar Suspension:</B> A Four-Bar Suspension is equivalent to a Four Link Suspension, except that the <I>4 links</I> are not adjustable (i.e. the location of the IC is fixed at design time).

    Most bicycle suspensions fall into the 4 bar category instead of the 4 link category because the <I>4 links</I> (bars) are typically not adjustable. Here is a picture of a <I>Four-Bar Suspension</I> with the 4-bars identified. Note that these 4 bars <I>do not</I> form a 4-bar linkage and note also that these 4-bars <I>do not</I> correspond to the 4-bars that you have identified.

    <img src="http://gallery.consumerreview.com/webcrossing/images/4-bar(2).jpg">
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    For the skeptics out there (and to show that I have not invented this definition myself), here are a few web links that include the definition of a 4 link suspension (and a 3 link suspension - more on that later):

    http://www.olywa.net/rdsrfr/Air%20Li...t is a 4-link?
    http://www.mattsoldcars.com/techinfo/dictionary.shtml
    http://www.autoglossary.com/term_4.html
    http://www.off-road.com/prerocker/glossary.html
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    Here is a picture of a typical Horst Link style Four-Bar. I have identified the 4 bars in the picture. Note that these 4-bars <I>do</I> correspond to the 4 bars in both pictures above, but that these 4-bars <I>do not</I> form a 4-bar linkage and that these 4-bars <I>do not</I> correspond to the 4-bars that you have identified. This bike is a Four-Bar.*

    <img src="http://gallery.consumerreview.com/webcrossing/images/horst.jpg">
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    The "4 Bars" we are talking about are the <I>4 bars</I> that isolate the axle from the chassis. A Faux-Bar suspension does not have these 4 bars at all. This is why a Faux-Bar <I>by definition</I> is not a Four-Bar. In other words, on a Faux-Bar the axle carrier (in this case the chainstay assembly) is not isolated from the chassis by 4 Bars. Instead, the axle carrier is connected directly to the chassis (similar to a Ladder Bar suspension). It's commonly called a Faux-Bar because it looks like a Four-Bar even though it's not.

    <img src="http://gallery.consumerreview.com/webcrossing/images/faux-bar.jpg">
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    I suppose you could argue that the mountain bike community has <I>redefined</I> the term "4-bar" to refer to any bicycle that uses a 4-bar linkage arrangement as a rear suspension system. Well, fair enough, but by this definition a hardtail with a Thudbuster seatpost would be a "4-bar". Is that really how you want to define the term "4-bar"? I would argue that common misuse of a term does not change the true definition of the term, especially when that term already has a well established definition. I also question the logic and reasoning behind redefining a term than has been used differently for decades.

    I like the term "Faux-Bar", because it draws a distinction between single pivot bikes that use a linkage to drive the shock and true four-bar designs. However, since there are many different types of four-bar bikes on the market (Horst, ICT, VPP, DW-Link, etc.) I think the term "Four-Bar" is much too vague and does lead to confusion because it is not used consistently (and the 3-bar discussion below makes it even more confusing). For these reasons, I guess I prefer to avoid using the term "Four-Bar" entirely, and try to use the terms Chainstay Pivot, Seatstay Pivot, VPP, DW-Link, etc. instead.
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    * This is for the (observant) nitpickers that may have noticed that the chainstay assembly on the XCE shown above is physically not 2 links, rather it is 1 physical link. Does this make the XCE a "3 Bar" then? The answer is yes, technically it does (at least by the automotive definition). This is a common suspension configuration in the automotive community as well, where the upper (or lower) two links are combined into one link, forming a 3-Bar (or 3-Link) suspension. However, it is conceptually and functionally equivalent to a 4-bar.

    <img src="http://gallery.consumerreview.com/webcrossing/images/3-bar_01(2).jpg">

    I hesitate to mention this here, because I think it may just confuse the issue. However, I think the fact that the name "3-Link Suspension" has nothing to do with a 3-bar linkage (it doesn't use 3-bar linkage at all) helps to illustrate the fact that the name "4-Bar Suspension" has nothing to do with whether or not it uses a 4-bar linkage (even though, coincidentally, 4-bar suspensions do use a 4-bar linkage).

    http://www.ffcobra.com/FAQ/3link.html
    http://www.auto-ware.com/shoptalk/3_4_lk.htm


    Apparently, not everyone in the mountain bike community is confused about this. Here is a "3-Bar Suspension" bicycle:

    <img src="http://gallery.consumerreview.com/webcrossing/images/3-bar.jpg">
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    To answer the original question. Four-Bar bikes and Faux-Bar bikes are visually very similar (well, at least Chainstay Pivot Four-Bar bikes are visibly similar to Faux-Bar bikes). However, conceptually they are very different. Conceptually, a Faux-Bar is a single pivot with a linkage that drives the shock. With a Faux-Bar, the IC (instantaneous center of rotation) and CC (center of curvature) of the rear axle are both fixed at the main pivot (as is the case with all single pivot bikes). With a Four-Bar suspension, the IC and CC can be placed anyplace in virtual space (thus the term VPP) and can move independently as the suspension cycles (the IC and CC don't even have to be physically located on the bike, and usually aren't).

    In regard to suspension design, there are many reasons that this may be an advantage. For example, the location of the IC has a large impact on how the bike behaves during braking. Being able to locate the IC anyplace in virtual space to help optimize braking performance is an advantage that Faux-Bar bikes do not have. However, that being said, in practice I think these differences are somewhat subtle and largely theoretical (at least when comparing chainstay pivot bikes and seatstay pivot bikes, I wouldn't necessarily say the same thing about other 4-bar bikes such as VPP, DW-Link, etc.). I have one of each (a Chainstay Pivot and a Seatstay Pivot), and I have yet to noticed any difference I could attribute to the location of the rear pivot (i.e. chainstay or seatstay). Then again, I don't charge into corners as hard and brake as aggressively as some do, so that may explain why I don't notice any difference (in other words, I'm not saying there isn't any difference, just that I don't notice any difference).
    Thanks for all the info, especially Backmarker. Great descriptions. I think it's nice to clarify some of the terms we all throw around and make sure we are on the same page. The bottom line is you have to ride! Ride on.
    Kokopelli Racing

    "Curb drops to flat, or curb drops to transition? There's a BIG difference there." Qfactor03

  51. #51
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    Wait a minute

    Thanks to Backmarker for a description of a 4-bar suspension design. But there is a good reason why MTB manufacturers don't use this term in the same way. Both the 4-bar and 3-bar suspensions refer to a design that allows the axle carrier to rotate around an axis defined by the drive shaft. The axis supports two wheels that need to be able to move independently, so this rotation is necessary. A bike has only one rear wheel, so rotation around this axis is not desirable. All MTB designs that I have seen mechanically join links 1 and 2, and links 3 and 4. This means that MTB rear suspension designs should be described as 2-bar. There is a single upper link (two mechanically joined seatstays) and a single lower link (two mechanically joined chainstays). The term 4-bar has been stretched to include any design that uses an upper and a lower link to separate the chassis from the axle carrier.

    I don't think you can make any generalizations about this linkage that hold for all possible permutations. I challenge anyone to assert a quality that universally holds for all suspension designs that qualify. A short list is the Horst link, VPP, DW-Link, QUAD (used by Marin), and Maestro. Check out the Titus Moto-Lite for an interesting new twist; it has a chainstay linkage in the traditional Horst location, but uses a counter-rotating upper link like a VPP design.

    My basic assertion is that the term 4-bar is useless. You need way more information to determine the characteristics of a given suspension design. The term faux-bar is just as bad since the pivot location is so important in determining performance characteristics.

  52. #52
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    Quote Originally Posted by gunfodder
    Thanks to Backmarker for a description of a 4-bar suspension design. But there is a good reason why MTB manufacturers don't use this term in the same way. Both the 4-bar and 3-bar suspensions refer to a design that allows the axle carrier to rotate around an axis defined by the drive shaft. The axis supports two wheels that need to be able to move independently, so this rotation is necessary. A bike has only one rear wheel, so rotation around this axis is not desirable.
    Well, you are correct in that autos and bicycles have different suspension requirements, so the upper and/or lower links are combined for different reasons (the links on bicycles suspensions are most likely combined to provide more torsional stiffness). However, the fact that they have combined the links for different reasons doesn't change the classification of the design.
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    Quote Originally Posted by gunfodder
    All MTB designs that I have seen mechanically join links 1 and 2, and links 3 and 4.
    Not all. Take another look at the XCE picture I posted. The upper two links are physically separate, so it's still a 3-bar.

    <img src="http://gallery.consumerreview.com/webcrossing/images/horst.jpg">
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    Quote Originally Posted by gunfodder
    This means that MTB rear suspension designs should be described as 2-bar. There is a single upper link (two mechanically joined seatstays) and a single lower link (two mechanically joined chainstays).
    Yes, I tend to agree, most would be classified as a 2-bar. However, I have never seen this term used (I used it in a discussion here before, but I have never seen it used elswhere).
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    Quote Originally Posted by gunfodder
    The term 4-bar has been stretched to include any design that uses an upper and a lower link to separate the chassis from the axle carrier.
    Yes, but remember that 2, 3, and 4-bar suspensions are derivations of the same design, are conceptually equivalent, and all fit into the same suspension category. Faux-bars are conceptually different. What we are really trying to do here is classify different suspension types based on their characteristics (single pivot, 4-bar, etc.). This is analogous to the animal kingdom where animals are classified (Reptile, Mammal, Fish, etc.) by their characteristics.
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    Quote Originally Posted by gunfodder
    I don't think you can make any generalizations about this linkage that hold for all possible permutations. I challenge anyone to assert a quality that universally holds for all suspension designs that qualify. A short list is the Horst link, VPP, DW-Link, QUAD (used by Marin), and Maestro.
    All Single Pivots share the quality that the IC and CC of the rear axle is fixed at the main pivot and both remain there throughout the entire range of travel.

    All Four-Bars (including the 2-bar and 3-bar derivations) share the quality that the IC and CC float in virtual space and are free to move through the range of travel. This quality is shared by all of the 4-bar bikes you have named.

    This is the primary characteristic that distinguishes these two designs. This is why a Faux-Bar doesn't fit in the Four-Bar category. With a Faux-bar, the IC and CC are fixed at the main pivot. This puts the Faux-Bar in the Single Pivot category, not the Four-Bar category.
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    Quote Originally Posted by gunfodder
    Check out the Titus Moto-Lite for an interesting new twist; it has a chainstay linkage in the traditional Horst location, but uses a counter-rotating upper link like a VPP design.
    It's not really new. This is the configuration used by the older style (well middle style) Jamis Dakars as well.
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    Quote Originally Posted by gunfodder
    My basic assertion is that the term 4-bar is useless. You need way more information to determine the characteristics of a given suspension design.
    The term 4-bar isn't really useless, because it refers to all of the suspension systems that have a floating (or virtual) IC and CC. However, the various 4-bar designs could easily be divided up into sub-classes of 4-bar as well (Horst, ICT, VPP, DW-Link, etc.).
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    Quote Originally Posted by gunfodder
    The term faux-bar is just as bad since the pivot location is so important in determining performance characteristics.
    The term Faux-bar isn't useless either for a couple of reasons. For one thing, it points out that the bike isn't a 4-bar. That isn't necessarily obvious at first glance, at least not to the layman. Also, it defines a sub-class of "Single Pivot", in which a 4-bar linkage is used to drive the shock. This linkage gives you more control over the suspension rate than you would have with a simple single pivot, and therefore is deserving of it's own sub-class.
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    Here is a simpler explanation using the animal kingdom as an example. Animals are classified into categories (Reptile, Mammal, Fish, etc.) based on their characteristics.

    So then, is a Dolphin classified as a Fish or a Mammal?

    Well, it certainly looks like a Fish. It has the components of a Fish (dorsal fin, tail fin, etc.). It lives in the water. It must be Fish then right? However, it's not classified as a Fish, because it has the characteristics of a Mammal (warm blooded, gives birth to live young, etc.) rather than the characteristics of a Fish.


    We are trying to do the same thing here with suspensions. We are trying to classify suspension types based on their characteristics.

    Single Pivot is a class having the characteristics that the IC and CC are fixed at the location of the main pivot.

    Four-Bar is a different class having the characteristics that the IC and CC float in virtual space.


    A Faux-Bar looks like a Four-Bar (like a Dolphin looks like a Fish). A Faux-Bar has the same components as a Four-Bar (just like a Dolphin has a dorsal fin, tail fin, etc.). However, a Faux-Bar has the characteristics of a Single Pivot (fixed IC and CC), so it is classified as a Single Pivot.
    Last edited by Backmarker; 01-06-2005 at 03:42 AM.

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    A Simpler Explanation

    Sorry. Didn't mean to make your head hurt .

    Did it make any sense?

    Here is a simpler example using the animal kingdom as an example that may be easier to digest.

    What we are trying to do by giving these designs different names (single pivot, four-bar, faux-bar, vpp, dw-link, etc.) is to classify suspension types based on their characteristics. This is analogous to the way animals are classified into categories (Reptile, Mammal, Fish, etc.) based on their characteristics.

    So then, should a Dolphin be classified as a Fish or a Mammal?

    Well, it certainly looks like a Fish. It has the components of a Fish (dorsal fin, tail fin, etc.). It lives in the water. It must be a Fish then right? Well, it's not classified as a Fish, because it has the characteristics of a Mammal (warm blooded, gives birth to live young, etc.) rather than the characteristics of a Fish.

    Single Pivot is a class of suspension having the characteristics that the IC and CC are fixed at the location of the main pivot.

    Four-Bar is a different class of suspension having the characteristics that the IC and CC float in virtual space.


    A Faux-Bar looks like a Four-Bar (like a Dolphin looks like a Fish). A Faux-Bar has the same components as a Four-Bar (like a Dolphin has a dorsal fin, tail fin, etc.). However, a Faux-Bar has the characteristics of a Single Pivot (fixed IC and CC), so it is classified as a Single Pivot.

    However, "Faux-Bar" also defines a sub-class of "Single Pivot", in which a 4-bar linkage is used to drive the shock. This linkage adds torsional stiffness to the rear end and gives you more control over the suspension rate than you would have with a simple single pivot, and therefore is deserving of it's own sub-class.

    I personally like the name "Faux-Bar". The word "faux" means not genuine or real; fake. This name cleverly illustrates the fact that a Faux-Bar is a Single Pivot masquerading as a Four-Bar.

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    First, I'm going to correct myself here before Steve gets a chance to do it for me. I got a bit carried away. The IC on the Flux is only a couple feet forward of the IC of the Element, not several as I stated in my previous post. The upper link needs to be a bit more parallel to the ground to place the IC several feet forward. Some of the older Ellsworth bikes did have the IC several feet forward.
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    Quote Originally Posted by ElementRaceRider
    It's bizarre to a layman like me that moving a pivot a couple inches away to the chainstay would make such a huge difference in leverage, as you put it. Not doubting ya, just amazed by that.
    Yeah, it's definitely not obvious just looking at the two designs. However, moving the IC a few feet doesn't necessarily make a big difference. Think of it this way, if you are pushing straight down on your 1 foot long crow bar, changing to a 4 foot long crow bar isn't going to make any difference as long as you keep pushing straight down. It depends on the direction of the force you are applying to the crow bar. The same principle applies to the IC. Moving it along the line of force may not have the same affect as moving it perpendicular to the line of force. So, just because the IC is a number of feet forward doesn't necessarily mean you will be able to feel the difference.
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    Quote Originally Posted by ElementRaceRider
    Since I (obviously) have the same bike, how would you describe the differences between your Element and the Turner?
    Well, that is a bit of a difficult question to answer because both bikes are setup very differently. The Element is air sprung front and rear and weighs under 24 lb. The XCE is coil sprung front and rear and weighs over 30 lb. So, it's hard to distinguish which differences are due to the components and which are due to the frame itself, but I will give a few random thoughts.

    I bought the Element in 1997 and it was my first full suspension bike and my first "real" mountain bike, so I didn't have much to compare it to (I went straight from an old fully rigid bike to the FS). However, I was transferred overseas on job assignment, so I ended up putting the Element in storage for about 5 years. During that time I owned several other bikes including a couple of hardtails, a Dakar, and finally the XCE.

    I recently had the Element shipped over here, so I had a chance to ride it again "fresh". Honestly, I expected it to be a step backwards from the XCE. However, I was pleasantly surprised to find out that it really isn't. It stacks up to the XCE very well. It's 3/4 lb. lighter (with the same shock), yet isn't noticeably flexier (a more aggressive rider might notice the difference, but I don't). Build quality is very good, maybe a tad behind the XCE because of some details like the grease ports, but it's pretty close (I still have the original pivots from 1997 and there is still no slop at all). All and all, it's a very nice bike.

    I mentioned before that the handling is very different. The head angle on the Element is about a degree steeper than the XCE (with both bikes using the length fork they were designed for) and the wheelbase is almost 2" shorter (my Element frame is a bit smaller than my XCE frame). The Element seems to have that magic balance between quickness and stability. You can change direction simply by twitching your hips, yet it never feels unstable. It's a blast through twisty single track. In contrast, the XCE feels slower and more stable. It's more like a motorcycle in that you steer it with the bars. Neither is better or worse, they are just different. If I'm out on a short aggressive training ride, I'll take the Element. If it's an all day epic on technical terrain I'll take the XCE.

    I've read many times that true four bars pedal better and brake better then faux-bars, but I haven't noticed that. Like I mentioned, my setups are very different, so that makes head to head comparisons difficult. But, I did spend some time back to back on rough climbs with sharp edges trying to detect suspension inactivity or pedal feedback and could not detect any on either bike.

    Faux-Bars also have a reputation for "bobbing" more than do Four-Bars. Well, I don't think the Element "bobs" more than the XCE, in fact I think it bobs less. I think the reason is the suspension rate. The XCE is rising rate, the Element is falling rate. With the XCE, I have to run a fair amount of sag to use full travel (25%-30%). With the Element, I can run less sag (15%-20%) and still use most of the travel. This gives the Element a firmer pedaling platform, and yet it still manages to handle medium and large hits well. The trade-off is that when running less sag the bike is not very plush on the small stuff (it's actually pretty harsh) and when running more sag you can run into bottoming problems. For this reason, I think I give the edge to the XCE in this department.

    I've tried braking through rough terrain to see if I can detect any brake stiffening, but I can't detect any on either bike. I did accidentally lock up the rear tire on the Element one time, but that was immediately after switching from knobbies to semi-slicks, so I think that was simply an issue of not having my braking fingers re-calibrated yet. However, it's really hard to say, because the XCE has 2.35" knobbies and a super plush coil shock whereas the Element has 2.0" semi-slicks and a fairly firm (and slightly sticky) air shock, so they feel different under braking.

    In the end, I need more time with both bikes setup the same way to make any real comparison on the performance of the rear suspensions themselves. I'm picking up a Fox Fork and an RP3 and I plan on swapping them back and forth between bikes over the next couple of years, so maybe I will get a better idea of the differences. Right now all I can say, is that differences in bike setup and component selection seem to make a much larger difference than do the rear suspension designs on these two bikes.

    .
    Quote Originally Posted by ElementRaceRider
    The Vanilla R on my bike blew it's damper so I was considering the Push platform damper upgrade instead of a simple overhaul from Fox. Is that a good match for the bike in your opinion?
    That's hard to say. I haven't tried any of the Pushed shocks yet and I'm not all that knowledgeable in regards to shocks in general. Some like the Push mods, some don't. I think it depends on what your preferences are. You should give the guys a Push a call, I've heard they know a little bit about shocks .

    How is your bike setup? Is it a light weight racer with an air fork, or a more of a trail bike setup with a coil fork? Would you prefer to have a bit better pedaling platform, or do you want the suspension to be a supple as possible? I think these are some of the factors that will help in the decision. I do think the falling rate suspension on the Element may match up better to an air shock, but maybe Push could make some mods that would make the coil work better with a falling rate design. Do you have any problems with bottoming the shock? I had an Vanilla R coil on my Element for a couple of years and I don't remember having any problems, but it was so long ago that I can't really remember.

    I've tossed around the idea of having the Vanilla RC on my XCE Push'ed, but I have decided against it for now. I may change my mind, but my current reasoning is as follows. The Vanilla is super supple and really, really works great on wet rough rocky and rooty climbs. So, it sort of fills a niche. You can just sit and spin and the bike just tracks straight over that stuff. I don't want to give up any of that suppleness in this situation, and I'm afraid that I would with the Push platform mod. So, I'm going to keep the Vanilla as it is, and get an air shock with a platform. I'll use the Vanilla paired with a coil fork in the early spring and late fall when the trail conditions are wet, and then switch to an air fork and platform air shock when the trails are dry during the summer months.

    But, your preferences may differ from mine. Give Push a call and tell them what you are looking for in a shock. They would know far more about it than I do.

  55. #55
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    Quote Originally Posted by Backmarker
    Not all. Take another look at the XCE picture I posted. The upper two links are physically separate, so it's still a 3-bar.

    <img src="http://gallery.consumerreview.com/webcrossing/images/horst.jpg">
    I would have to disagree that the upper links (driving the shock) are seperate. They are constructed of two parts, but they cannot act independantly when assembled.

    Good thread, though!

    -David

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    Quote Originally Posted by Backmarker
    I bought the Element in 1997 and it was my first full suspension bike and my first "real" mountain bike, so I didn't have much to compare it to (I went straight from an old fully rigid bike to the FS)...Honestly, I expected it to be a step backwards from the XCE. However, I was pleasantly surprised to find out that it really isn't. It stacks up to the XCE very well. It's 3/4 lb. lighter (with the same shock), yet isn't noticeably flexier (a more aggressive rider might notice the difference, but I don't). Build quality is very good, maybe a tad behind the XCE because of some details like the grease ports, but it's pretty close (I still have the original pivots from 1997 and there is still no slop at all). All and all, it's a very nice bike...The Element seems to have that magic balance between quickness and stability. You can change direction simply by twitching your hips, yet it never feels unstable. It's a blast through twisty single track.
    Thanks for your thoughts. I'm on my second Race, broke the '97 in a crash and replaced it with a 99. It was also my first full suspension bike. I've since ridden (but not owned) other FS bikes including some very expensive ones and haven't felt the need at all to upgrade. I love the handling for exactly the reasons you mention, suits my riding perfectly. I would like to add a Freeride machine at some point though for the high speed stability and steep downhill capabilities they have. My friend's Uzzi SL is an absolute blast to ride at ski resorts but not so much fun locally.

    I've read many times that true four bars pedal better and brake better then faux-bars, but I haven't noticed that. Like I mentioned, my setups are very different, so that makes head to head comparisons difficult. But, I did spend some time back to back on rough climbs with sharp edges trying to detect suspension inactivity or pedal feedback and could not detect any on either bike.
    I have, but it's rare. Only happens on the big ring when pedaling lightly over sharp bumps. Next time you pull the shock out, shift the bike to the big/small gears and move the rear end through it's travel, you'll see the crank twist.

    That's hard to say. I haven't tried any of the Pushed shocks yet and I'm not all that knowledgeable in regards to shocks in general. Some like the Push mods, some don't. I think it depends on what your preferences are. You should give the guys a Push a call, I've heard they know a little bit about shocks .
    I did but didn't get into what to expect. On the order form I mentioned that I'm not concerned about bobbing just want it plush but I'll clarify that with them today before sending it in. Fox will rebuild the shock a lot cheaper but all they can do is put one of their unreliable dampers in it - the 99 Vanilla's were known to blow and this will be the second time for me.

    Thanks again.

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    Quote Originally Posted by fallzboater
    I would have to disagree that the upper links (driving the shock) are separate. They are constructed of two parts, but they cannot act independently when assembled.

    Good thread, though!

    -David
    True, you (and gunfodder) do make a good point (and I don't disagree with the 2-bar designation). The upper and lower links never act independently on a bicycle, so there are definitely some differences between the bicycle and auto implementations. Bicycles have different suspension requirements than do cars, so the implementation is bound to be different. Circle track and drag racing suspensions have different requirements, so their implementations are different from each other as well. On a bicycle you don't want the upper and lower links to operate independently, so you can combine them. However, combining the links doesn't change the location of the IC or CC, and I think that's really the key. At least that's my opinion.

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    allow me to retort

    As fallzboater mentioned the upper links cannot move independently. They are mechanically joined at each of the three pivot points. The links in your diagram move independently on their own pivots.

    Let me modify my original statement slightly to more accurately convey my meaning: the terms 4-bar and faux-bar are meaningless to the rider. Riding characteristics that matter are things like stiffness, brake-jack, bob (both seated and standing), etc. The classifications of 4-bar and faux-bar do not guarantee any of these riding characteristics. It is interesting to the engineer to note that 4-bar designs have a dynamic IC, but the rider cares more about how well the suspension performs.

  59. #59
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    Quote Originally Posted by DeeEight
    To drudge up another suspension definition from the old days, a mac-strut is a frame where the shock is rigidly attached to/serving as part of a stress bearing frame member (in the case of Amp B1 thru B4s for example, the shock was rigid with the seatstay which the wheel attached to).
    Those all have Horst links - Horst Leitner designed and built them - the only difference between them and a 4-bar is there isn't another pivot driving the shock. If I'm following the techie talk so far it works the same way as far as the rear axle is concerned. Hard to believe his main business now is pickup bed extenders, huh? Well that, and collecting checks from Specialized...

  60. #60
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    Quote Originally Posted by gunfodder
    Thanks to Backmarker for a description of a 4-bar suspension design. But there is a good reason why MTB manufacturers don't use this term in the same way. Both the 4-bar and 3-bar suspensions refer to a design that allows the axle carrier to rotate around an axis defined by the drive shaft. The axis supports two wheels that need to be able to move independently, so this rotation is necessary. A bike has only one rear wheel, so rotation around this axis is not desirable. All MTB designs that I have seen mechanically join links 1 and 2, and links 3 and 4. This means that MTB rear suspension designs should be described as 2-bar. There is a single upper link (two mechanically joined seatstays) and a single lower link (two mechanically joined chainstays). The term 4-bar has been stretched to include any design that uses an upper and a lower link to separate the chassis from the axle carrier.

    I don't think you can make any generalizations about this linkage that hold for all possible permutations. I challenge anyone to assert a quality that universally holds for all suspension designs that qualify. A short list is the Horst link, VPP, DW-Link, QUAD (used by Marin), and Maestro. Check out the Titus Moto-Lite for an interesting new twist; it has a chainstay linkage in the traditional Horst location, but uses a counter-rotating upper link like a VPP design.

    My basic assertion is that the term 4-bar is useless. You need way more information to determine the characteristics of a given suspension design. The term faux-bar is just as bad since the pivot location is so important in determining performance characteristics.

    Actually the definition of a four bar linkage is how it looks in side profile. The automotive four bar becomes a 5 or 6 bar when you start counting links (panhard rod or watts linkage), but in side profile it's a four bar. Likewise the automotive 3 bar is still a four bar in side profile and in a straight line that's how it behaves.
    The term 3 bar can only really describe a macpherson strut where one bar can change length. The term "2 bar" just doesn't work.

    Which is why you can classify the suspension designs as as either monopivot, macPherson strut or four bar.

    Faux bars are monopivots that look like four bars.

    The reality with bicycle faux bars is the suspensions almost all behave the same. The location of the main pivot varies little between the designs due to the constraints of the BB, chainrings and derailleur/chainguide.
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    You described the current definition of a 4-bar suspension for MTBs. I understand it and I think it makes sense.

    I had a hard time believing that all faux-bar designs use the same pivot point, but I do recall that virtually all designs I have seen use a low pivot behind the seat tube. Most high pivot bikes are monoshock designs. But I couldn't leave well enough alone, so I checked out the Kona website. It looks like the pivot location for their long travel designs (like the Stab) are much higher than that of their shorter travel bikes (like the Kikapu). This makes sense; a fixed IC/CC means you have to optimize for the intended usage of the bike.

  62. #62
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    Quote Originally Posted by Dougal
    Actually the definition of a four bar linkage is how it looks in side profile. The automotive four bar becomes a 5 or 6 bar when you start counting links (panhard rod or watts linkage), but in side profile it's a four bar. Likewise the automotive 3 bar is still a four bar in side profile and in a straight line that's how it behaves.
    The term 3 bar can only really describe a macpherson strut where one bar can change length. The term "2 bar" just doesn't work.

    Which is why you can classify the suspension designs as as either monopivot, macPherson strut or four bar.

    Faux bars are monopivots that look like four bars.

    The reality with bicycle faux bars is the suspensions almost all behave the same. The location of the main pivot varies little between the designs due to the constraints of the BB, chainrings and derailleur/chainguide.
    I was about to make exactly the same point. An MTB suspension is only kinematically 2-dimensional, so there's not much point in counting left and right hand chainstays and rocker halves as individual links. It's geometry is defined entirely in the side profile. The rocker is 1 link (From it's pivot centre to the seat stay only. The other side of the rocker from the pivot to the shock is not relevant to the axle path since it only affects the motion ratio of the wheel to shock movement). The seat stays are only 1 link. The chainstays are only 1 link and the final link is the seat post itself (considered the fixed link since the axle path will be referenced relative to it). Engineers define any simple mechanism like this as a 4-bar-linkage, which causes all the massive confusion. Of course everyone with a little knowledge can work out that if the wheel hub is attached directly to the chainstay, then the axle path is a simple fixed arc with the dynamic wheel rate defined by the shock linkage geometry. I think the term "single pivot with a linkage actuated shock" is a good description in this case. However, if the wheel hub is attached instead to the seat stay, then the axle path becomes a little more complex because neither end of this link is attached directly to the seatpost (fixed link). Then all the b***s**t kicks off and the posts start getting longer and more exotic!

    In the second case above you can draw a direct analogy with a double wishbone car suspension. The rocker and chainstays are analogous to the upper and lower wishbones respectively and the seatstays are analogous to the upright (hub carrier). The only difference (and it is very signifcant when it comes to design parameters) is that the plane of wheel rotation is 90 degrees offset. Anyway I'm digressing now and just thinking aloud.....I'm still getting my head round MTB geometry and the relevant design parameters.

  63. #63
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    Quote Originally Posted by gunfodder
    You described the current definition of a 4-bar suspension for MTBs. I understand it and I think it makes sense.

    I had a hard time believing that all faux-bar designs use the same pivot point, but I do recall that virtually all designs I have seen use a low pivot behind the seat tube. Most high pivot bikes are monoshock designs. But I couldn't leave well enough alone, so I checked out the Kona website. It looks like the pivot location for their long travel designs (like the Stab) are much higher than that of their shorter travel bikes (like the Kikapu). This makes sense; a fixed IC/CC means you have to optimize for the intended usage of the bike.
    Yes the Stab and stinky primo are an exception, they're dedicated DH bikes which I don't think can be run with a front derailleur or multiple front rings.
    The stinky and stinky deelux are their long travel freeride bikes (7") which have the same pivot position as all their other faux bars.
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  64. #64
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    For the love of God....

    Quote Originally Posted by yangpei
    I recently read an article in a British MTB mag about different types of full suspension. They break full suspensions into 5 groups:

    1. Single pivot - Orange
    2. Four-bar - Horst link on chainstay, isolating suspension from pedalling / braking
    3. Faux-bar - Pivot is above dropouts on the seatstay, behave like single pivot bikes.
    The linkages are there to help drive the shock.
    4. VPP - Blur, Spider
    5. Floating drivetrain - GT i-drive, Maverick

    I had not previously encountered the term "faux-bar suspension". I was wondering if any of the suspension gurus on mtbr could elaborate on the differences between four-bar and faux-bar suspensions. Thanks.
    yangpei, I am sure these responses exceeded your expectations....

    But really, WHO CARES ABOUT ANY OF THIS ?!?!?!?!?!?

    If you have a bike and like it, ride the thing. If you are looking to buy a bike, ride the bikes you think you might like and are considering.....then buy the one you like best that fits your budget. At least that is what dumb blonds like me do when they buy new bikes. Maybe I am just lucky or my primitive algorithm just works.

    Cheers

  65. #65
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    Quote Originally Posted by spinjocky
    I seriously think it's time to get a few FAQ threads on the topic! (e.g. one for Wheel path, and one for Shock linkages.)

    Also there's URT (unified rear triangle not common any more), Giant Maestro, DW-link, and Marin (whyte) linkages. Can't think of any others at the moment.
    Cause this FAQ will not have a nice FAA (Frequently Answered Answer). There is such a copious amount of pseudo scientific mumbo-jumbo on the topic (especially from the Horst link lovers) as to render a possibility of an intelligent discussion next to useless.

    Just buy a good bike from a good company. That's the answer.

  66. #66
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    All of the automotive crap might make sense if bikes worked like auto stuff, but since bikes work perpendicular to automotive suspension, it's kind of a moot point and you are trying to use a term from one area to describe something entirely different in an entirely different area.

    I'm suprised no one has really mentioned this yet.

    Go back to those cute illustrated pictures of the turner...You can't classify the mountain bike using the automotive criteria because the automotive suspension works in an entirely different way. To get an idea, the wheel would have to be mounted 90° to the left or right of where it is now.
    I know in my heart that Ellsworth bikes are more durable by as much as double. AND they are all lighter...Tony Ellsworth

  67. #67
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    Quote Originally Posted by Jm.
    All of the automotive crap might make sense if bikes worked like auto stuff, but since bikes work perpendicular to automotive suspension, it's kind of a moot point and you are trying to use a term from one area to describe something entirely different in an entirely different area.

    I'm suprised no one has really mentioned this yet.
    Actually automotive stuff is directly relevant. Think about a car with trailing rear suspension (four bar or single pivot). The behaviour is directly related to a bikes rear suspension.
    Or stand at the front of a car and imagine cornering forces on the front suspension. This is again directly relevant to an accelerating mountainbike.

    I have a strong suspicion that Busby's GT LTS is simply a car double wishbone suspension, the shock has been scaled down and the wheel turned sideways.
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  68. #68
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    Quote Originally Posted by FoShizzle
    yangpei, I am sure these responses exceeded your expectations....

    But really, WHO CARES ABOUT ANY OF THIS ?!?!?!?!?!?
    Well I hate to point out the obvious, but this is a tech-talk forum.

    It's quite easy (in fact it takes no effort) to avoid becoming embroiled in threads you do not care about.
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  69. #69
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    Quote Originally Posted by MartyRey
    When did Specialized get the Horst Link patent?? There was no Specialized sticker on my retired LTS2. Also, how many out there think Specialized is a horse's arse for making everyone pay homage to them for using a Horst Link?
    About 1998/99 I think. Horst sold it because he was tired of chasing after patent violators like GT, and he had gotten the US patent on pickup truck bed extenders, and there's more money in being a Tier 1 OEM supplier to GM, Ford, Chrysler, Toyota, etc, than in selling bicycle frames/forks. He likewise sold the cable-actuated hydraulic disc design to Rockshox a year or so earlier because he had a new fully-hydraulic design about ready for production. But then he decided to get out of bicycles altogether so....

    The basic problem is the US patent office employs morons who'll grant patents without any regard to pre-existing patents, so even though the horst-link patent predated the ICT patent, and the ICT clearly violates the horst-link patent in using the same type of dropout, they gave a patent anyways, and defeating patents in lawyer heaven US of A is expensive work. Brass Eagle was THE largest paintball gun company in the world even before their merger into K2, and they used that sorta wealth that comes with that size a company to defend their patents enthusiastically. Now since the merger and access to even more money for lawyers, they've gone nuts taking everyone who even remotely violated their patents to court. Specialized just doesn't have the kinda of money involved to do that, and it'd probably turn out that the horst-link patent was public domain info anyways as pictures were appearing in magazines over a year before the first patent application was filed (and US patent rules state that you only have 1 year from an invention going public to file for a patent).
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    Quote Originally Posted by Dougal
    Yes you're right, it's a seatstay pivot. Sometimes my typing fingers don't listen and I'm not having much luck editing that post right now.

    Specialized has the patent because Horst Lietner designed some bikes for them in the early stages (early 90's). It wasn't until about 2000 that they started enforcing the patent which is well after LTS days.

    If you don't like it then sorry but that's how the world works. There'd be fewer good inventions if people and organisations couldn't protect their intellectual property.
    Correction, Specialized BOUGHT the patent from Horst because he was looking to get out of bikes and was tired of chasing patent violators. Specialized was looking to stick it to competitors like GT anyway they could and were willing to go after patent violators so they bought the patent from Horst.

    The bought it before the GT i-drive design came into production, and it was because GT wasn't a horst-link licensee than the STS/LTS design got canned when it did.
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  71. #71
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    Quote Originally Posted by Dougal
    Well I hate to point out the obvious, but this is a tech-talk forum.

    It's quite easy (in fact it takes no effort) to avoid becoming embroiled in threads you do not care about.
    fair enough......

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    Cannot agree more

    Quote Originally Posted by FoShizzle
    well said......

    also be aware that many of these arguments will be based on theoretical arguments which while they may hold at that level, do not translate into a practical difference that will matter to you.

    the ride of a bike is a multivariate equation if you will.....with many variable perhaps independently important, but when added to the equation along with the other important variables, may not matter so much and will often have interaction effects that become important..

    bottom line.....in my simple mind, if the implementations is solid based on virtually any common linkage, it can be a killer bike with its own pluses and minuses, subtle or otherwise.

    cheers
    I am quite convinced that almost any well executed bike suspension design set up
    carefully to a rider personal needs will perform very well. In my experience, and with modern frames, shock, fork and .. tires have more influence on a bike performance than almost anything else.

    Example: my 5-spot with a fox float shock with no platform is a dog uphil: you can only climb effectively while seated and keeping a smooth cadence. Same bike with a Romic and Stratos ID fork climbs almost like a race bike. Is it the frame? No, it is the suspension ...

  73. #73
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    Quote Originally Posted by Davide
    I am quite convinced that almost any well executed bike suspension design set up
    carefully to a rider personal needs will perform very well. In my experience, and with modern frames, shock, fork and .. tires have more influence on a bike performance than almost anything else.

    Example: my 5-spot with a fox float shock with no platform is a dog uphil: you can only climb effectively while seated and keeping a smooth cadence. Same bike with a Romic and Stratos ID fork climbs almost like a race bike. Is it the frame? No, it is the suspension ...
    Of course the shock and fork are going to have a big impact. They are the basis of the suspension. But here we're discussing the performance of one specific area of a bikes suspension (the dropout pivot location). Swapping the shocks and forks are irrelevant to the discussion.

    I disagree with you on the 5-spot performance with the float. One of my shocks is an AVA float (non propedal). I had no problem with the climbing performance, only with the weak midstroke which is characteristic of most air shocks.

    If you flail about on any suspended bike then it'll let you know. It wouldn't be suspension if it didn't. The only way you'll beat that is with a very harsh damping platform or by sorting out your pedal stroke.
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    Quote Originally Posted by FoShizzle
    yangpei, I am sure these responses exceeded your expectations....

    But really, WHO CARES ABOUT ANY OF THIS ?!?!?!?!?!?

    If you have a bike and like it, ride the thing. If you are looking to buy a bike, ride the bikes you think you might like and are considering.....then buy the one you like best that fits your budget. At least that is what dumb blonds like me do when they buy new bikes. Maybe I am just lucky or my primitive algorithm just works.

    Cheers
    The problems with being an engineer:-

    You have to try to understand how everything works (especially cars, bikes, etc)
    You can't help opening your mouth when you disagree about how everything works
    Once you have understood (or at least think you have) how everything works you have to have the very best ($$$$)
    If there is a newer/better one, you have to upgrade to it (more $$$) after understanding how it works, exactly how much better it is etc etc.

    As an engineer myself, I suffer all of the above. My wife on the other hand is the total opposite. She just rides her bike and I check it beforehand to make sure it still works! Something pretty drastic has to go wrong before she notices. I wish I was like this, life would be sooo much simpler.

  75. #75
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    Quote Originally Posted by Jm.
    All of the automotive crap might make sense if bikes worked like auto stuff, but since bikes work perpendicular to automotive suspension, it's kind of a moot point and you are trying to use a term from one area to describe something entirely different in an entirely different area.

    I'm suprised no one has really mentioned this yet.

    Go back to those cute illustrated pictures of the turner...You can't classify the mountain bike using the automotive criteria because the automotive suspension works in an entirely different way. To get an idea, the wheel would have to be mounted 90° to the left or right of where it is now.
    I mentioned this actually in a post somewhere above, but here is the relevant part again if you missed it:-

    "You can draw a direct analogy with a double wishbone car suspension. The rocker and chainstays are analogous to the upper and lower wishbones respectively and the seatstays are analogous to the upright (hub carrier). The only difference (and it is very signifcant when it comes to design parameters) is that the plane of wheel rotation is 90 degrees offset. Anyway I'm digressing now and just thinking aloud.....I'm still getting my head round MTB geometry and the relevant design parameters."

    Despite this, the automotive "crap" you mention is still very relevant. At the end of the day it's all about vehicle dynamics, you just have to be clever enough to apply the correct parameters for each individual "vehicle".

  76. #76
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    Quote Originally Posted by FoShizzle
    But really, WHO CARES ABOUT ANY OF THIS ?!?!?!?!?!?
    Some do, some don't. I for one am glad that there are people out there thinking about, designing, and producing better frames, forks, shocks, brakes, hubs, etc. for mountain bikes. I bought my first MTB in 1986. It was state-of-the art at the time. It was fully rigid, weighed over 30 lb., and had really cool biopace chainrings . I had fun riding it, but today's full suspension bikes are light years ahead of that bike and have taken mountain biking to a whole other level.
    .
    .

    Quote Originally Posted by FoShizzle
    If you are looking to buy a bike, ride the bikes you think you might like and are considering.....then buy the one you like best
    A lot of people seem to think that test rides are the holy grail. I don't buy into that philosophy at all. For one thing, finding all of the bikes you are interested in in your size is not always possible or practical. Second, bike setup makes a huuuuge difference. If you test ride a bike that is setup poorly or fits you poorly you are likely to get a bad impression of the bike. Third, it can take a long time to get a bike dialed in for you. It can take weeks just to get things like the brakes, shock, and fork broken in and dialed in. Test riding is a tool. Reading rider reviews and magazine reviews is another tool. Understanding the physics and understanding what the designer of the bike was trying to accomplish is another tool. You can choose to use which ever tools you want when you pick your bike. If you don't find these posts interesting, don't read 'em.
    .
    .

    Quote Originally Posted by FoShizzle
    Maybe I am just lucky or my primitive algorithm just works.
    What works for one person doesn't necessarily work for everyone. Some people are easily satisfied, others aren't. You and I have the same bike (Element). Based on many of the comments you've made (here and in other posts), I would say that you are very happy with your choice. So, your approach seems to have worked for you. I on the other hand, am not completely happy with mine. I think there are a couple of key areas where the suspension performance is lacking (for my personal preferences) and I would like to improve the performance in those areas.

    When I bought the XCE, I set out to do just that. I relied mostly on magazine reviews, rider reviews, and other rider feedback. Based on what I read, I thought the Horst link would improve suspension performance in those areas (haven't you heard, the Horst link solves every suspension problem known to man ). Well, I think I'm one of about 3 guys globally who bought a Horst link bike and didn't think it was the greatest thing since sliced bread (perhaps because the bike I had was already pretty darn good). To make a long story short(er), the suspension performance wasn't better in any of the areas that were important to me (and I wouldn't have been able to determine that from a test ride, it took several months to really get to know the bike).

    When I bought the XCE, I didn't spend much time trying to understand the theoretical stuff. If I had, I would have realized that the Horst link attempts to solve problems that don't exist for me, and I would have started to look at other designs. This time, I'm making an attempt to understand the theoretical stuff a bit better. These types of discussions help.
    Last edited by Backmarker; 01-07-2005 at 09:10 AM.

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    Quote Originally Posted by gunfodder
    As fallzboater mentioned the upper links cannot move independently. They are mechanically joined at each of the three pivot points. The links in your diagram move independently on their own pivots.
    Yes, you made a good point about that. I didn't address it because there are many different applications and implementations of 4-bar suspensions and understanding the differences between all of them is far beyond the scope of my suspension knowledge. Road racing, circle track racing, dirt track racing, and drag racing all use different variations of the 4-bar design to acheive different things. I used drag racing suspensions as examples because I think they are closer in design to a mountain bike suspension than is a road racing or circle track racing suspension. In drag racing, you aren't turning corners and you don't necessarily want the rear axle to rotate about the drive shaft axis as you would with a circle track car (at least not for the same reasons). But, of course there are still some differences between 4-bar implementations on cars and bikes. There are differences between Dolphins and Humans too, but they are still both classified as Mammals.
    .
    .

    Quote Originally Posted by gunfodder
    Let me modify my original statement slightly to more accurately convey my meaning: the terms 4-bar and faux-bar are meaningless to the rider. Riding characteristics that matter are things like stiffness, brake-jack, bob (both seated and standing), etc. The classifications of 4-bar and faux-bar do not guarantee any of these riding characteristics. It is interesting to the engineer to note that 4-bar designs have a dynamic IC, but the rider cares more about how well the suspension performs.
    I disagree whole heartedly with that statement. The best example I can think off the top of my head is the giant NRS. It has unique ride characteristics, and those ride characteristics would not be acheivable with a faux-bar. Initially, due to patent issues, Giant was going to release the NRS in the states with a seatstay pivot (they even built some, because I have seen pictures of them). Those seatstay pivot bikes would have felt much different then the current NRS chainstay pivot bikes <I>to the rider</> and the bike wouldn't have had the ride characteristics they were shooting for.
    .
    .
    Last edited by Backmarker; 01-07-2005 at 04:54 AM.

  78. #78
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    automotive stuff is extremely relevant

    Quote Originally Posted by Dougal
    I have a strong suspicion that Busby's GT LTS is simply a car double
    wishbone suspension, the shock has been scaled down and the wheel turned sideways.
    All of the more interesting and perhaps more efficient bike designs come from auto design
    engineers. RM ETSX, GIANT NRS, MARIN QUAD etc. And the GT LTS.

    I had been away from biking for about 10 years when I finally dusted off my hybrid back
    in the mid 90's only to discover I couldn't take the pounding any more. I wasn't aware of
    the advancements in full suspension until I hit the trails and saw all the modern marvels.

    Went shopping and the first time I saw the GT LTS I thought "I've seen that suspension before".
    YES.. the front end of my Lotus Super Seven or my Lotus Formula Ford, turned sideways.
    (those days are long behind me...early 70's) Bought the GT LTS, still have it. Great bike BUT
    had some serious deficiencies in the braking department. Now have an RM ETSX. Another
    great bike without any deficiencies that I'm aware of: all thanks to the automotive world.

    Edit:

    The image I posted earlier of the Lotus Super 7 Three Bar is actually from this site
    http://my.voyager.net/~quadrant19/
    The Caterham Super Seven is a modern resurrection of the original Lotus Super 7.
    I raced a Lotus 7, same chassis, smaller engine. 1200cc I think. I buddy of mine
    raced a Lotus Super Seven with the 2 liter overhead twin-cam Lotus engine.
    Mine was fast for its class but his was a bloody rocket, in any class.

    michael
    Last edited by mrdy; 01-07-2005 at 06:48 AM.
    "Be not afraid of going slowly but only of standing still." - Chinese Proverb

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    Quote Originally Posted by Backmarker
    What works for one person doesn't necessary work for everyone. Some people are easily satisfied, others aren't. You and I have the same bike (Element). Based on many of the comments you've made (here and in other posts), I would say that you are very happy with your choice. So, your approach seems to have worked for you. I on the other hand, am not completely happy with mine. I think there are a couple of key areas where the suspension performance is lacking (for my personal preferences) and I would like to improve the performance in those areas.

    When I bought the XCE, I set out to do just that. I relied mostly on magazine reviews, rider reviews, and other rider feedback. Based on what I read, I thought the Horst link would improve suspension performance in those areas (haven't you heard, the Horst link solves every suspension problem known to man ). Well, I think I'm one of about 3 guys globally who bought a Horst link bike and didn't think it was the greatest thing since sliced bread (perhaps because the bike I had was already pretty darn good). To make a long story short(er), the suspension performance wasn't better in any of the areas that were important to me (and I wouldn't have been able to determine that from a test ride, it took several months to really get to know the bike).

    When I bought the XCE, I didn't spend much time trying to understand the theoretical stuff. If I had, I would have realized that the Horst link attempts to solve problems that don't exist for me, and I would have started to look at other designs. This time, I'm making an attempt to understand the theoretical stuff a bit better. These types of discussions help.
    That's a very good point. Before I bought my last bike I made an effort to understand various designers philosophies and referenced them against my own knowledge of automotive engineering and vehicle dynamics. I did also read all the reviews and test rode the bikes on my shortlist. In the end I bought a Ventana X5 (FoShizzle has one of these too by the way) based on Sherwood's design philosophy, good reviews in the press and a positive test ride. The fact that it does not have a trendy Horst Link was fairly irrelevant to me. I decided this was not an important consideration for my particular needs.

    This approach however is a lot more difficult for people with non-engineering backgrounds as they are a lot more vulnerable to marketing b***s***. I think even a lot of press journalists struggle to understand too. They certainly do in my field of motorsport anyway.

  80. #80
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    Quote Originally Posted by mrdy
    All of the more interesting and perhaps more efficient bike designs come from auto design
    engineers. RM ETSX, GIANT NRS, MARIN QUAD etc. And the GT LTS.
    Also Ellsworth's ICT design is the brainchild of Mike Kojima, a racecar engineer associated with Nissan.

  81. #81
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    Quote Originally Posted by DeeEight

    The bought it before the GT i-drive design came into production, and it was because GT wasn't a horst-link licensee than the STS/LTS design got canned when it did.
    I don't see how that can be true since there is a GT patent for the STS/LTS design that has an earlier date than the Horst patent.

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    Pedal Feedback

    Quote Originally Posted by ElementRaceRider
    I have <I>(felt pedal feedback on the Element)</I>, but it's rare. Only happens on the big ring when pedaling lightly over sharp bumps. Next time you pull the shock out, shift the bike to the big/small gears and move the rear end through it's travel, you'll see the crank twist.
    That's interesting, I've been trying to generate it in the small ring/big cog combo, but perhaps it's more noticeable in the big ring. I'll have to try it in the big ring and see if I can feel it. However, you might just be more sensitive to it then I am. I have a hard time distinguishing the feeling of the bump itself from pedal feedback. The XCE has a bit more chain growth than does the Element, so if you can feel it on the Element I would think that you would probably feel it on the XCE as well. However, perhaps there's more to it than just chain growth, I'm not really sure.

  83. #83
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    Quote Originally Posted by uktrailmonster
    I mentioned this actually in a post somewhere above, but here is the relevant part again if you missed it:-

    "You can draw a direct analogy with a double wishbone car suspension. The rocker and chainstays are analogous to the upper and lower wishbones respectively and the seatstays are analogous to the upright (hub carrier). The only difference (and it is very signifcant when it comes to design parameters) is that the plane of wheel rotation is 90 degrees offset. Anyway I'm digressing now and just thinking aloud.....I'm still getting my head round MTB geometry and the relevant design parameters."

    Despite this, the automotive "crap" you mention is still very relevant. At the end of the day it's all about vehicle dynamics, you just have to be clever enough to apply the correct parameters for each individual "vehicle".
    I don't think turning an independent suspension sideways is the way to go as far as bicycle application of motorsport technology is concerned. Rather it's what Backmarker is showing us. A solid rear axle supported by twin parallel 4-bar linkages, as used in drag racing, offers the closest analogy. Now the wheel is turning in the same plane as the suspension.

    What people discussing this topic often misunderstand is that the anti-squat calculation is determined by the angle of the line from rear contact point to instant center, not from the axle path pe se. This is of couse modified by the chain line. Motorsports theorists, both for cars and motorcycles, understand this perfectly well.

  84. #84
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    Quote Originally Posted by ElementRaceRider



    I have, but it's rare. Only happens on the big ring when pedaling lightly over sharp bumps. Next time you pull the shock out, shift the bike to the big/small gears and move the rear end through it's travel, you'll see the crank twist.



    .
    What you should see there is the crank twist forward as the derailer pulls the slack out of the chain. That's the opposite of pedal feedback. You could call it negative feedback and I think I've heard it called fallaway or dropaway.

  85. #85
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    Quote Originally Posted by uktrailmonster
    That's a very good point. Before I bought my last bike I made an effort to understand various designers philosophies and referenced them against my own knowledge of automotive engineering and vehicle dynamics. I did also read all the reviews and test rode the bikes on my shortlist. In the end I bought a Ventana X5 (FoShizzle has one of these too by the way) based on Sherwood's design philosophy, good reviews in the press and a positive test ride. The fact that it does not have a trendy Horst Link was fairly irrelevant to me. I decided this was not an important consideration for my particular needs.
    It's interesting that you mention that. When I was shopping last time, I completely eliminated Ventana from my search because of the lack of the Horst link. Partially, it was simply because I already had a seatstay pivot bike so I wanted to try a chainstay pivot bike and find out for myself if I could notice any differences. But, partially it was also because the reviews and discussions I had read left me with the impression that the Horst link provides some advantages that it really doesn't. I suspect that a lot of people eliminate "faux-bar" bikes from their shopping list for these very same reasons, and in many cases they are the wrong reasons.
    .
    .

    Quote Originally Posted by uktrailmonster
    This approach however is a lot more difficult for people with non-engineering backgrounds as they are a lot more vulnerable to marketing b***s***. I think even a lot of press journalists struggle to understand too. They certainly do in my field of motorsport anyway.
    Bicycle suspension is surprisingly difficult to analyze (at least it is for me). Much more so than it would seem at first glance. Even some with technical backgrounds have difficulty (myself included). It's not just the motorsports journalists that struggle with the technical stuff. MTB mags are notorious for getting the technical stuff wrong. Well, at least in the states. The UK mags I've read seem to be better, at least I have read a couple of different tech articles in the UK where the writer drew a distinction between four-bars and faux-bars (although I have read at least one tech article in a US mag that did so as well, so there is hope ).
    .
    .

  86. #86
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    I got interested in bike suspension theory back in '99 when I bought a used pre-ICT Truth and switched all the components over from the '97 Jamis Dakar I was then riding. The two bikes had very close basic geometry--head angle, TT length, etc.--and almost identical axle paths. The Dakar was a faux bar, as you know, with pivot locations very close to a Ventana.

    The difference between the performance of the two bikes was to me large and obvious. I won't go into detail except to say that the Dakar felt somewhat "plusher" but on the Truth I tended to ride one or two gear ratios higher.

    I've been trying to explain why this would be true ever since.

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    I'm not going to go so far as to say that there aren't any differences, because my bikes are setup so differently that they do ride very differently, so it's hard to distinguish differences due to components from differences due to suspension design. I guess I was expecting it to be one of those slap-you-along-side-the-head type of things that you would really notice, and it hasn't been that way for me. In terms of suspension performance, the bikes seem to be more similar than they are different.

    As of right now, I haven't noticed any of the things normally attributed to single pivots (lack of suspension activity while climbing, pedal feedback, brake stiffening, increased bobbing, etc.). I think partially, it's because both bikes have similar CC locations and similar amounts of anti-squat geometry. I also think it's partially because high forward single pivot designs have given single pivots in general a bad reputation. However, I need more time, so I will hold off judgment for now. I planning on setting the bikes up with the same components and doing some more testing. Maybe I'll even learn something in the process.

  88. #88
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    Quote Originally Posted by Backmarker
    Some do, some don't. I for one am glad that there are people out there thinking about, designing, and producing better frames, forks, shocks, brakes, hubs, etc. for mountain bikes. I bought my first MTB in 1986. It was state-of-the art at the time. It was fully rigid, weighed over 30 lb., and had really cool biopace chainrings . I had fun riding it, but today's full suspension bikes are light years ahead of that bike and have taken mountain biking to a whole other level.
    .
    .


    A lot of people seem to think that test rides are the holy grail. I don't buy into that philosophy at all. For one thing, finding all of the bikes you are interested in in your size is not always possible or practical. Second, bike setup makes a huuuuge difference. If you test ride a bike that is setup poorly or fits you poorly you are likely to get a bad impression of the bike. Third, it can take a long time to get a bike dialed in for you. It can take weeks just to get things like the brakes, shock, and fork broken in and dialed in. Test riding is a tool. Reading rider reviews and magazine reviews is another tool. Understanding the physics and understanding what the designer of the bike was trying to accomplish is another tool. You can choose to use which ever tools you want when you pick your bike. If you don't find these posts interesting, don't read 'em.
    .
    .



    What works for one person doesn't necessarily work for everyone. Some people are easily satisfied, others aren't. You and I have the same bike (Element). Based on many of the comments you've made (here and in other posts), I would say that you are very happy with your choice. So, your approach seems to have worked for you. I on the other hand, am not completely happy with mine. I think there are a couple of key areas where the suspension performance is lacking (for my personal preferences) and I would like to improve the performance in those areas.

    When I bought the XCE, I set out to do just that. I relied mostly on magazine reviews, rider reviews, and other rider feedback. Based on what I read, I thought the Horst link would improve suspension performance in those areas (haven't you heard, the Horst link solves every suspension problem known to man ). Well, I think I'm one of about 3 guys globally who bought a Horst link bike and didn't think it was the greatest thing since sliced bread (perhaps because the bike I had was already pretty darn good). To make a long story short(er), the suspension performance wasn't better in any of the areas that were important to me (and I wouldn't have been able to determine that from a test ride, it took several months to really get to know the bike).

    When I bought the XCE, I didn't spend much time trying to understand the theoretical stuff. If I had, I would have realized that the Horst link attempts to solve problems that don't exist for me, and I would have started to look at other designs. This time, I'm making an attempt to understand the theoretical stuff a bit better. These types of discussions help.
    I take it back!!!! In fact, so much so that I am now going back to school to get a graduate degree in Engineering just so I can follow you folks

    I actually do appreciate this info....when i am not too lazy to read it. I guess it is just that I was crunching difficult numbers too much at work yesterday and picked a thread that simply would not let me turn my mind off

    Cheers and thanks for the info!

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    Quote Originally Posted by Steve from JH
    I don't see how that can be true since there is a GT patent for the STS/LTS design that has an earlier date than the Horst patent.
    The key isn't when the patent was issued, but when it was filed. And also the fact the US patent system allows existing applications to be replaced and extended into new applications (the old ones are dropped, but the earliest filing date is what's considered when it comes to prior art claims). Horst filed the first patent claim Jan 26th 1992. GT was only just getting the RTS frames into the pipeline for their team riders at the time and nobody outside the racing world had even seen one yet.
    I don't post to generate business for myself or make like I'm better than sliced bread

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    Quote Originally Posted by FoShizzle
    I take it back!!!! In fact, so much so that I am now going back to school to get a graduate degree in Engineering just so I can follow you folks

    I actually do appreciate this info....when i am not too lazy to read it. I guess it is just that I was crunching difficult numbers too much at work yesterday and picked a thread that simply would not let me turn my mind off

    Cheers and thanks for the info!
    Shizzle, from what I've seen of your previous posts you already put quite a lot of thought into your bike choice and components and use your common sense well. You ended up with a Ventana too, so that was a wise purchase!

  91. #91
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    Quote Originally Posted by Steve from JH
    I got interested in bike suspension theory back in '99 when I bought a used pre-ICT Truth and switched all the components over from the '97 Jamis Dakar I was then riding. The two bikes had very close basic geometry--head angle, TT length, etc.--and almost identical axle paths. The Dakar was a faux bar, as you know, with pivot locations very close to a Ventana.

    The difference between the performance of the two bikes was to me large and obvious. I won't go into detail except to say that the Dakar felt somewhat "plusher" but on the Truth I tended to ride one or two gear ratios higher.

    I've been trying to explain why this would be true ever since.
    I think it's very difficult to compare bike geometry (eg Horst v single pivot), even if the two bikes you are comparing have otherwise very similar basic geometry and componentry. The less obvious (or should I say the less well documented) parameters often make the comparison invalid. For example if one of the bikes is significantly torsionally stiffer than the other, then this will undoubtedly affect the result. The bike manufacturers themselves are in the best position to test geometry concepts because of course they can build prototypes that are otherwise identical.

  92. #92
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    Quote Originally Posted by uktrailmonster
    Shizzle, from what I've seen of your previous posts you already put quite a lot of thought into your bike choice and components and use your common sense well. You ended up with a Ventana too, so that was a wise purchase!
    thanks.

    unlike you engineer nerds, I am a pathetic mathematician nerd.........I simply created a model-based simulation which suggested that with 95% confidence, the Ventana X-5 would make me the most happy compared to the other bikes considered.......I am now working on a model to select the next pick of California lottery numbers

    Cheers

  93. #93
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    the physical principles of pivots, linkages, forces and dampers are identical between auto suspension and bicycle or motorcycle suspension design

    it ends there

    a car wheel does a lot of things that a bicycle wheel does not, and vice versa. let's also not forget that an internal combustion-driven wheel generates a lot different forces, centripetal and otherwise, than a human leg-driven wheel.

  94. #94
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    The Element can have positive feedback depending on your point of view

    Quote Originally Posted by Steve from JH
    What you should see there is the crank twist forward as the derailer pulls the slack out of the chain. That's the opposite of pedal feedback. You could call it negative feedback and I think I've heard it called fallaway or dropaway.
    I cycled the swingarm of my Element up and down and measuring chain length between top of chain ring and top of rear cog. During the down stroke of the cranks the chain length shrinks about 1/2 a chain link at most (which induces bob and can be imagined as power loss). But when the cranks go through the vertical position the spring of the shock pushes the swing arm back down and pulls the chain forward 1/2 a chain link. Now if you are pedalling smoothly the 1/2 link that the chain is pulled forward returns the power loss from the down stoke and smooths out the power transfer to the rear wheel so that there is no spiking of power (can be an advantage for extreme technical climbing where you want constant power to the wheel without fluctuations - such as you don't want power reduction when cranks are vertical and you don't want excessive torque which might spin tire when cranks are horizontal). I actually prefer to pedal on pavement with my shock unlocked, and when doing extemely high cadence sprints to improve my pedalling technique (cadence > 150 strokes per minute) - it feels like my butt isn't bounced on the saddle as much (such as I can pedal faster with a fixed gear track bike).
    The 1/2 link that the chain is pulled foward can be felt as pedal kick back when the rear wheel hits a rock in such a way as to extend the swingarm and your legs are locked (such as when you might suddenly hestitate in a pedal stroke in a boulder field to time the next pedal stoke to not smash your pedal into a rock).
    Since I'm light and pedal with a relatively high cadence I prefer low mono pivots and Ellsworth type 4 bars to high mono pivots (or the various VPP and 4 bars that try to extend the swing arm on the power stroke to reduce bob). Now if I was heavier, a powerful sprinter with a choppy pedal stroke and raced NORBA short tracks vs. BC's extemely technical XCs, I might prefer the high mono pivots and VPPs. At least in Canada there is still the opertunity to win Masters and Vet Expert races on the downhill and just wheel suck on gravel road sections.
    Last edited by ccm; 01-07-2005 at 12:24 PM.

  95. #95
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    Quote Originally Posted by Dougal
    If you flail about on any suspended bike then it'll let you know. It wouldn't be suspension if it didn't. The only way you'll beat that is with a very harsh damping platform or by sorting out your pedal stroke.
    ...or using more advanced suspension geometry.

    With nearly the same travel and more as a 5-Spot, a DW link or Jon Whyte will pedal seated or standing like a race bike using a non-platform air or coil shock AND have less kickback feel than any Turner, ICT or other old style of suspension, no matter how square you pedal.

    The ride is the proof of what works best for each rider.

    - ray

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    Quote Originally Posted by gonzostrike
    a car wheel does a lot of things that a bicycle wheel does not, and vice versa.
    Such as?

    Quote Originally Posted by gonzostrike
    let's also not forget that an internal combustion-driven wheel generates a lot different forces, centripetal and otherwise, than a human leg-driven wheel.
    Such as? The numbers are vastly different and engines don't bounce up and down like humans, but other than that they both transfer torque to the driven wheels.

  97. #97
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    Here's my background on the issue.

    I started shopping for my first FS bike back in 1996 when I was in high school. I spent a year begging a ride on every bike I could (from both riders, racers and shops) before I narrowed it down.
    From those test rides I ended up with only 3 bikes which I liked the pedalling behaviour. The Specialized AIM, the GT LTS and the Proflex 856. The dbr's and other faux bars I rode just felt mushy.
    I noticed the pedal kickback on the proflex in the granny rings and the $NZ1000 between the specialized AIM and the LTS2 settled the deal for me.

    I was intruiged by the differences in performance I had noticed and started trying to figure out why. It took me about four years of pondering before I had the differences nailed down enough to explain it to the average punter without watching their head spin.

    Something that needs pointed out here is a horst link is not a guarantee of performance. A bike like the trek fuel has a rear end that acts almost like a rigid triangle. Whether you put a horst link or seatstay pivot in that rear end would matter not at all as it wouldn't rotate enough to matter.
    But on bikes with upper and lower links that come close to parrallel (5 spot, NRS etc) the dropout pivot location starts to influence the design in a major way.

    The last time I rode a faux bar in anger (k2 tirade) I was shocked to have the rear end spit out sideways when I tried to feather the back brake around the first corner.

    People don't seem to realise that regarding chain tension and pedal feedback a horst link bike isn't much different from a faux bar. The difference comes from the suspensions reaction to acceleration which determines how much it squats under power.
    Take a look at how low the back end of a faux bar sinks when cimbing and you'll see what I mean.
    Owner of www.shockcraft.co.nz and NZ Manitou Agent.
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    Quote Originally Posted by Dougal
    Here's my background on the issue.

    I started shopping for my first FS bike back in 1996 when I was in high school. I spent a year begging a ride on every bike I could (from both riders, racers and shops) before I narrowed it down.
    From those test rides I ended up with only 3 bikes which I liked the pedalling behaviour. The Specialized AIM, the GT LTS and the Proflex 856. The dbr's and other faux bars I rode just felt mushy.
    I noticed the pedal kickback on the proflex in the granny rings and the $NZ1000 between the specialized AIM and the LTS2 settled the deal for me.

    I was intruiged by the differences in performance I had noticed and started trying to figure out why. It took me about four years of pondering before I had the differences nailed down enough to explain it to the average punter without watching their head spin.

    Something that needs pointed out here is a horst link is not a guarantee of performance. A bike like the trek fuel has a rear end that acts almost like a rigid triangle. Whether you put a horst link or seatstay pivot in that rear end would matter not at all as it wouldn't rotate enough to matter.
    But on bikes with upper and lower links that come close to parrallel (5 spot, NRS etc) the dropout pivot location starts to influence the design in a major way.

    The last time I rode a faux bar in anger (k2 tirade) I was shocked to have the rear end spit out sideways when I tried to feather the back brake around the first corner.

    People don't seem to realise that regarding chain tension and pedal feedback a horst link bike isn't much different from a faux bar. The difference comes from the suspensions reaction to acceleration which determines how much it squats under power.
    Take a look at how low the back end of a faux bar sinks when cimbing and you'll see what I mean.
    Yes not all "Horst links" are great

    I got interested in these suspension discussions back in late 1999 when I got a high forward monopivot, a Superlight. And it climbed much quicker and saved much more energy climbing than my first full suspension bike a sorter travel (2.75 inch travel Litespeed Obed FS) "Horst link" with Horst’s own AMP Research rear suspension.

    Where I live is much long climbs like one half to over an hour long relentless climbs sometime steep, usually fairly smooth trails with some modernly rough sections of loose rock.

    After claiming nothing could climb better I began to notice some pedal kickback and cadence stalling when I climbed through the rough rocky sections on my Superlight. So I began my search for a smoother pedaling bike that could climb as well.

    I tried all kinds of bikes, monopivots, faux-bars, ICT, and other “Horst links”. I found that the energy saving bikes for climbing as well as my Superlight that also were smooth pedaling were a few Horst links, the RacerX, Turner XCE, and Intense Tracer. I bought the Tracer due to a few factors, the main factor was that it was adjustable in suspension geometry and I wanted to test the options that could be set to the other bikes that rode best for me.

    I now realize that my first “Horst Link” even with Horst’s own linkage bobbed so much more than even longer travel Horst links I had tested because the main pivot was an inch too low at the frame compared to what Horst designed. The difference was amazing. I can climb as good as the Superlight, but with better traction and pedaling smoothness.

    The XCE (now the lighter weight Burner) climbed as well but was not adjustable and heavier. The RacerX had shorter travel and actually climbed possibly better than the Tracer, but was not adjustable. The Truth bobbed much more and handled and braked rather poorly compared to most bikes I tested, it climbed steep bumpy areas very well but the Superlight handled and braked better and the other Horst links handed and braked much better when ridden hard.

    I’m a big guy 6’2” and near 200 lbs. I think the top Horst link bikes have a wide range of sag adjustment that can be fine tuned to accommodate many sizes and weights of riders. While ICT like lower monopivots are best suited for light weight riders and high monopivots or similar pathed multilinks work very well for heavier riders who need to climb a lot.

    But I’ve since tested longer travel Horst links than my 4 inch Tracer and other types and nearly all longer travel bike are better handling and climbing using platform damping. Only the DW-Link and Jon Whyte longer travel designs work better without platform damping. These apparently use paths that are better balanced for squat than longer travel Horst and single pivots while changing below sag quickly to be as compliant to bump as a longer travel low monopivot or horst link.

    It’s a fun obsession to try to understand the path effects and balances of frame suspension and damping.

    - ray

  99. #99
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    Quote Originally Posted by Backmarker
    It's interesting that you mention that. When I was shopping last time, I completely eliminated Ventana from my search because of the lack of the Horst link.
    He he - I completely eliminated Ventana because of the price tag! My very favorite bike back in '97 was the Marble Peak, but I couldn't afford one. Then I noticed that a little Canadian company made a bike that looked just like one, so I found a dealer, took a ride and took it home. Totally different feel than the Marble Peak but great in it's own way.

  100. #100
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    Quote Originally Posted by Dougal
    I disagree with you on the 5-spot performance with the float. One of my shocks is an AVA float (non propedal). I had no problem with the climbing performance, only with the weak midstroke which is characteristic of most air shocks.

    .
    Dougal, let not restart a fight, it all a matter of degree.

    With the float the 5-spot climbs but it does not climb as well as with the ROMIC, and for me the float really only worked while seated or in "careful" out of the saddle efforts.

    The 5-spot with the float (5" travel) is not much different than my GT with a a Stratos air (4.75"): you can climb of course but you want to be careful because the bikes bob quite easily ...

    And about bikes ... I am not sure, I recently tried a Ventana and it is just outstanding, I lik e VPP a lot for climbing and small bump compliance, so maybe I like everything but I can't wait to try iron-horse stuff (because with an 5" horst+platform you do loose small bump compliance) ... .
    Last edited by Davide; 01-07-2005 at 07:50 PM.

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