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  1. #1
    HYH
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    575 Modified Single Pivot vs Motolite 4 Bar Linkage

    I own a Titus Motolite( 1 year) and recently taken delivery of the 575. There has been so much bad press on single pivot designs so buying the 575 was a leap in faith based purely on reviews. Based on only 1 week of riding( 4 rides) which has been enjoyable but detrimental to my work as I have been coming in late , the 575 is every bit as good as the reviews and advertisement tell you.

    Single pivot designs are supposed to suffer from the firming of suspension during braking. But I don't seem to experience any firming on the rear during braking and the suspension seems just as active as the Motolite. Are there any suspension gurus who can explain this observation?

    I remember reading somewhere that single pivot designs have been successfully used for DH bikes as designers are able to place the pivot for the downhill conditions. This seems logical. But locating the ideal pivot fo the 575 would be more difficult as it would be used for both XC and All Mountain where the ideal pivot point would vary.

    The Foes FXR and Commencal are also single pivot design bikes reknown for their performance.So, is the Four Bar Linkage still superior to single pivot design or is there some trade off in the 575 that I am not aware of.

  2. #2
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    the brake-stiffening problem, just about every company has figured out how to prevent that. It was a problem with early suspension designs - before the bike industry knew anything about suspension. I have an old, 1st generation GT dualie where hard braking would actually compress the shock... talk about weird, at least it didn't stiffen...

    The big advantage of 4-bar designs (as a broad catagory, I'm calling 4-bars basically bikes that don't have a "main" pivot, or put another way, bikes that have 2 pivots between the rear axle and the main frame. these include: FSR, VPP (and other similar types such as DW and giant), Maverick, rocky mountain ETSX, Marin, and Ellsworth) is that they can decouple drive forces from suspension action - not saying they all do, just that isn't really possible with a single pivot design. Thing is, these days propedal and other "platform" dampers can overcome this pretty well, at least on frames like the 575 where the chain isn't trying to extend the damper (you can imagine a bike with a really high pivot (the main pivot on my old GT was about halfway up the seat tube), all the "platform damping" in the world isn't going to stop bobbing if you are riding with any sag whatsoever). On downhill bikes you tend not to hammer hard out of the saddle, so more chain growth is permissable compared to a bike that's going to be climbing.

    IMO the real genius of the Yeti design is the damper/spring actuation. Most FSR designs seem to ignore tailoring the leverage ratio vs compression/travel relationship, probably because the FSR design is supposed to be so good.

  3. #3
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    So glad you are enjoying your old school no marketing hype single pivot! We here at Go-Ride take great joy in poking fun at fancy 4 bar bikes that work just like low single pivot bikes.
    In theory the ML, being a HL 4 bar bike, has a near vertical wheel path offering neutral braking and climbing feel. Since the link on the ML hangs upside down and swings immediatly foreward the link pulls the wheel foreward with it. The Horst Link is located below the axle so that helps to push the rear end backwards to compensate, but not enough to keep a near vertical wheelpath. What you end up with is a wheelpath that is very similar to the location of most low single pivots.
    In terms of braking, the higher the pivot is the more brake induced squat you get. Since the 575's pivot is fairly low there is not much brake squat so it feels pretty active. Some 4 bar bikes like an Ellsworth for example have very neutral braking since the strut that the wheel and brake are attached to stay in a somewhat stationary angle as the suspension compresses since the chainstay and the link are similar in length. On the ML the seatstay of which the brake is attached dips down a bit since the link is upside down and swings. The braking ends up feeling quite similar to the single pivot once again.
    Even when the link lays flat and is near parallel to the chainstay you are only achieving marginally better wheelpath which is only apparent late in the travel where you are not pedaling anyway. David Turner realised this and abandoned the 4 bar desigh for 2006 so he could actually gain some brake squat, stiffness and avoid un necessaey patent licencing.
    Brake induced squat is very personal. No one wants sloppy climbing but some people like some brake squat so the bike stays more level and does not weight the front wheel so much while descending. Others notice the loss of rear wheel traction and a bit of chatter over braking bumps and want the suspension to be more active.

    Moral of the story: If you believe in 4 bar it had better be truely moving near vertival with a long parallel linkand/or well placed HL or you might as well build a single pivot and gain stiffness of a large swingarm.

    Since you own both bikes and they are really quite simialar i'm interested in hearing how they compare. I'm guessing 575 feels more plush since it has more travel, but tell us what else you find out!

    Krispy
    Currently enjoying life Giant Trance Advanced 27.5/Rockshox Pike/Sram XX1
    Giant STP

  4. #4
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    [QUOTE=
    IMO the real genius of the Yeti design is the damper/spring actuation. Most FSR designs seem to ignore tailoring the leverage ratio vs compression/travel relationship, probably because the FSR design is supposed to be so good.[/QUOTE]

    Yes, this is the whole other half of the story,the great ride that Yeti has engeneered to work with the modern air shock! This is what sold me on the bike.
    Currently enjoying life Giant Trance Advanced 27.5/Rockshox Pike/Sram XX1
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  5. #5
    HYH
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    Based on a vector diagram or simple schematic, single pivot bikes as a general rule should exhibit more chain growth and suspension firming than 4 Bar systems. My theory on why the 575, Heckler, Foes FXR single pivot designs work well is primarily due to 2 reasons :
    1. Designers now have better software to locate a more optimum pivot location for a given frame geometry especially under load.
    2. Advancement in Shock design as in the DHX 5 and Curnutt.

    Why I bought the 575 when I already have an ML?
    I wanted another bike for a more plush ride with longer legs without going over 28Lbs. I was also sold on the rising linkage rate feature which in theory should provide a more superior and plush ride over minor bumps.

    I also love the simplicity in the single pivot design and in the case of the 575, I was and still am intrigued by the carbon fibre pivots on the seat stay. I don't know if they actually contribute to the performance of the suspension as the do not flex very much but I love the idea of it. I actually looked very hard at the Foes FXR but I found that the bike had too much low speed chatter. I also love the unique look of the 575 and the combination of aluminium with carbon. It is too me, a very beautiful bike.

    Comparison between the ML and 575.
    I have only logged in 4 rides, each about 2 hours over moderate terrain on the 575. Therefore, I am still more comfortable and confident with the ML especially on technical downhill sections. Also, the components are not equivalent. DHX 5 Air and 07 Talas 32 vs RP3 and Revelation for the 575 and ML. I use Nevegal's for both bikes.

  6. #6
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    Great Thread!

    This is a great thread! I know this topic is regularly discussed on mtbr (comparisons of various suspension designs that is) but the explanations and examples used in this thread are so far exceptional. Nice work.

  7. #7
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    the key is damping

    Quote Originally Posted by Joules
    IMO the real genius of the Yeti design is the damper/spring actuation. Most FSR designs seem to ignore tailoring the leverage ratio vs compression/travel relationship, probably because the FSR design is supposed to be so good.
    Agree. Having owned an FSR and currently riding a Blur (Pushed) and an ASR-SL I firmly believe the genius of the Yeti is in the damping. The spring rate is dialed in for sure across the travel range, but that isn't too difficult to do on the first order with software or basic geometry and hand calculations. It is the spring in conjunction with the damping that is just dialed. They clearly have adjusted the linkage rates with lots of knowledge about the damping. I'm not so sure there are software programs for that. This is where the Yeti employee's riding experience and relationship with Fox likely payed off as the process was more likely trial and error. You can feel how well it works in the controlled way the rear wheel handles bumps - it just takes the bump and is instantly ready for the next. On the Blur it takes longer for the bump force reverberate through the system.
    M

  8. #8
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    Hey Motivated, can you tell us how both bikes behave (blur and yeti ASR-SL) in different terrains. I have a blur with 5th element, I think yetis are beatiful but is impossible to try one in my area before buying.

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    I'm selling the Blur

    I like bikes (and cars for that matter) that are tight, responsive and predictable. The Blur has very good rear susp. and I wish I left it stock with the Fox AVA, but I "Pushed" it which ended up with a much more muted feel. The Blur likes fast rebound damping or it packs up. The Yeti takes small sharp hits better than the Blur -it's just thunk and done. Like throwing putty at a wall. The Blur resonates more. The Blur is laterally stiff, but sometimes it spookes me because the steering is actually faster than the Yeti. There is no doubt the Yeti climbs way better, but that is partially due to the component spec. - my Yeti weighs 22.6lb and the Blur is like 28, 29, I don't care. Comparing downhill ability is difficult. On really choppy straight stuff, the Blur might be better, but the Yeti is better through ruts and through fast swoopy terrain the Yeti is great - actually freakin outstanding. I'm just tired of the Blur - it isn't nearly as rewarding to ride. I hope to sell it and buy a carbon or Ti 29er hardtail. I figure that would be really reliable, good for road and trail work and be good to train on. I try not to ride the Yeti because it is so setup for racing.

    Oh yeah, and the Blur has an absolutely stupid number of bearings.

    Quote Originally Posted by navajose
    Hey Motivated, can you tell us how both bikes behave (blur and yeti ASR-SL) in different terrains. I have a blur with 5th element, I think yetis are beatiful but is impossible to try one in my area before buying.
    Last edited by Motivated; 09-18-2006 at 03:50 PM.
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  10. #10
    HYH
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    Below is an extract of my discussion via email with Yeti recently and reproduced here with permission by Yeti.

    Carbon Fibre Insert on the swing arm
    Does the insert pivot? I was looking at the geometry and the alignment looks too straight and the insert too stiff to allow for any potential for pivoting. If it does pivot, does this action not make it a faux bar? Also your web site makes no mention about the humble carbon fibre insert. Strangely enough, it was one of the reasons I bought the bike as I actually thought that it was a pivot and I liked the idea of a maintenance free pivot.
    Yeti: Yes the carbon flex pivot does move, just slightly towards the end of the travel. Having the flex pivot does not characterize the frame as a four bar; it would still be considered a modified single pivot.

    Dogbone swing link and the rising rate Leverage Ratio
    I have read in the reviews that the 575 has a rising rate leverage ratio. But I do not see any mention of this on your web site and I can't see anything on the bike's geometry that indicates this. If the 575 is indeed design with a rising rate ratio, can you explain how this is achieved?

    Yeti: Most every bike on the market in a broad sense has a rising rate meaning the bikes compression becomes stiffer towards the end of the stroke (the rate rises). But you can not pigeon hole the ratio plot to one term since the ratio changes at every position of travel, which makes every bikes ratio plot different. We have optimized out ratio plot for the characteristics we want in our bikes. For the 575 bikes starts out supple in the beginning stoke and has a linear rate linear throughout the middle or bulk of the travel and then ramps up at the tail end of the stroke. This makes the bike feel bottomless and really active for a ride with 5.75” of travel.

    Modified single pivot?
    The marketing theme by manufacturers who sell vpp or horst link bikes is that in a single pivot, the suspension is apparently less active under hard braking as braking forces are not isolated. Apparently, careful design and placement of the single pivot can only mitigate this problem. Is this true? How does the 575 overcome this problem.

    Yeti: This is definitely true. Good design is good design. You could have all the best theories in the world but in the real world testing we have not found the 575 to be less active under braking. This is due to our careful manipulation of the above-mentioned ratio plot. On paper it would tell you otherwise, but we have tested it over and over again. It is all about the ride, and we feel that in a ride quality test we will win out again and again against any other manufacture.

  11. #11
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    Quote Originally Posted by krispy@go-ride.com
    So glad you are enjoying your old school no marketing hype single pivot! We here at Go-Ride take great joy in poking fun at fancy 4 bar bikes that work just like low single pivot bikes.
    In theory the ML, being a HL 4 bar bike, has a near vertical wheel path offering neutral braking and climbing feel. Since the link on the ML hangs upside down and swings immediately forward the link pulls the wheel forward with it. The Horst Link is located below the axle so that helps to push the rear end backwards to compensate, but not enough to keep a near vertical wheelpath. What you end up with is a wheel path that is very similar to the location of most low single pivots.
    In terms of braking, the higher the pivot is the more brake induced squat you get. Since the 575's pivot is fairly low there is not much brake squat so it feels pretty active. Some 4 bar bikes like an Ellsworth for example have very neutral braking since the strut that the wheel and brake are attached to stay in a somewhat stationary angle as the suspension compresses since the chainstay and the link are similar in length. On the ML the seatstay of which the brake is attached dips down a bit since the link is upside down and swings. The braking ends up feeling quite similar to the single pivot once again.
    Even when the link lays flat and is near parallel to the chainstay you are only achieving marginally better wheelpath which is only apparent late in the travel where you are not pedaling anyway. David Turner realised this and abandoned the 4 bar design for 2006 so he could actually gain some brake squat, stiffness and avoid un necessaey patent licencing.
    Brake induced squat is very personal. No one wants sloppy climbing but some people like some brake squat so the bike stays more level and does not weight the front wheel so much while descending. Others notice the loss of rear wheel traction and a bit of chatter over braking bumps and want the suspension to be more active.

    Moral of the story: If you believe in 4 bar it had better be truly moving near vertical with a long parallel link and/or well placed HL or you might as well build a single pivot and gain stiffness of a large swingarm.

    Since you own both bikes and they are really quite similar I'm interested in hearing how they compare. I'm guessing 575 feels more plush since it has more travel, but tell us what else you find out!

    Krispy

    Wow! You've managed to state the exact opposite of what I've experienced having owned a ML for near two years, compared to all the single pivot bikes I've ever ridden? From the first time I through a leg over my ML, I couldn't believe how uncoupled it was from peddling and braking. If anything IMO the only difference in the mac strut and other Horst link bikes is the ability "of my Titus anyway" to make it so much stiffer.

    Having said that, if I were to look into other bikes the stiffness of the FXR, and the glowing reviews of the 575 would put them at the top of the list of bikes I'd be seriously considering. And that list is very tiny.

  12. #12
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    I was looking into this same subject back when I was trying to decide between the ML and the 575. It came down to demo riding both bikes but in the process of searching the specs and design of the 575 I did come out with some good knowledge about the Yeti and some of the differences.

    The Yeti's design genius is in the carbon flex pivots and the dogbone. The carbon flex pivots offer some resistance as does the dogbone in the beginning of the stroke and as the dogbone reaches its apex the suspension becomes more linear. If you look at the 2 diagrams, one of the 575 and the other is the ML, you can see the difference in that the ML is a rising rate suspension and the Yeti is more linear but as it reaches the end of the stroke it quickly becomes a rising rate suspension. The linear range is what makes it feel so plush.

    When you look at the diagram of the motolite it is strictly a rising rate suspension. The Linkage program does show that the ML has less pedal kickback and chain extension but neither is really noticeable on the Yeti to the rider.

    To me the 575 kicked some ML butt but the opinions vary on this wildly where the rider is concerned. I will say that the 575 does require the sag to be set correctly at 25% to 30% in order for you to reap the benefits of the suspension. When it's dialed in the trail just seems to disappear.

    The last image does show that the ML has less chain growth than the 575 but to be honest, if you don't feel it when you ride, what difference does it make?
    Attached Images Attached Images

  13. #13
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    don't understand

    Quote Originally Posted by iviguy
    I was looking into this same subject back when I was trying to decide between the ML and the 575. It came down to demo riding both bikes but in the process of searching the specs and design of the 575 I did come out with some good knowledge about the Yeti and some of the differences.

    The Yeti's design genius is in the carbon flex pivots and the dogbone. The carbon flex pivots offer some resistance as does the dogbone in the beginning of the stroke and as the dogbone reaches its apex the suspension becomes more linear. If you look at the 2 diagrams, one of the 575 and the other is the ML, you can see the difference in that the ML is a rising rate suspension and the Yeti is more linear but as it reaches the end of the stroke it quickly becomes a rising rate suspension. The linear range is what makes it feel so plush.

    When you look at the diagram of the motolite it is strictly a rising rate suspension. The Linkage program does show that the ML has less pedal kickback and chain extension but neither is really noticeable on the Yeti to the rider.

    To me the 575 kicked some ML butt but the opinions vary on this wildly where the rider is concerned. I will say that the 575 does require the sag to be set correctly at 25% to 30% in order for you to reap the benefits of the suspension. When it's dialed in the trail just seems to disappear.

    The last image does show that the ML has less chain growth than the 575 but to be honest, if you don't feel it when you ride, what difference does it make?
    Hey Iviguy
    This is beyond my comprehension. Can you offer some explanations to the graphs?.
    How do you read this?.
    Regards
    GB

  14. #14
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    Quote Originally Posted by GreenBonty
    Hey Iviguy
    This is beyond my comprehension. Can you offer some explanations to the graphs?.
    How do you read this?.
    Regards
    GB
    LOL... I'll explain as best as I have been able to wrap my mind around it anyway....

    The Force Characteristics graphs show the mm of travel along the horizontal axis. The vertical axis is representative of the amount of force being applied to push the suspension back. Below is directly from the program's manual:
    Progressivity – used in two ways – in a geometrical sense and regarding forces. Geometrical progressivity describes the changing of the leverage ratio throughout the travel. A progressive rate suspension means lower values of the leverage ratio for larger travel. A falling rate suspension is the opposite. A linear rate suspension keeps a constant leverage ratio. These affect the “feel” of the suspension. If we take forces into the account as well, we talk about the “real” progressiveness of the suspension. This represents the changing of the rate between the force needed to compress the suspension to a specific travel position, and the balancing force performed by the shock. Thus, a progressive suspension “stiffens up” at larger travel positions, while a falling rate suspension feels really plush and is easier to bottom out. Bike designers tune their suspension for the desired behavior. Short travel cross-country bikes usually use a progressive setup, while downhill bikes usually use a more linear setup to be able to absorb repeated larger bumps. For “freeride” bikes, a progressive setup is optimal at the end of travel to prevent harsh bottom outs on big jumps.

    Forces (vertical and axle-path tangent directional)
    The program calculates the relation between vertical forces acting to the rear wheel and the shock compression that it causes. It is calculated as if we mounted the mainframe to a solid stand and pushed up the rear wheel more and more, monitoring the wheel movement amount and the force value.
    Actually, the gradient of this (red line) shows the real progressivity of the bike suspension.
    Progressivity is also affected by the shock characteristics, which can be changed to several types. See the editing section for more information on how to change this.
    There are two kinds of force diagrams – vertical and axle-path tangent directional.
    The vertical case calculates the force acting to the wheel (axle) in a perfectly vertical direction (compared to the main frame’s initial position). This may differ more or less from real-life scenarios since mountain bike riders go over varying terrain, but it is adequate to show the characteristics of the suspension.
    The axle-path tangent directional case means that the rear wheel force direction is recalculated for each position to match the direction of the axle path. Thus the curve can be used to determine the total energy input to the suspension at a given travel by integrating it (counting the area below it).


    The Force Characteristics for the 575 basically show that it has a more linear design. A rising rate suspension means that as the shock is compressed further into it's travel it will increase the force to return to normal. All shocks would be rising rate by their design. The further you go into the suspension the harder it is to compress the shock. So by the same token, a falling rate suspension would be opposite. A linear rate suspension is going to be more equal in the force throughout the travel of the suspension.

    So basically what you can see with the 575 forces graph is that because the line is fairly horizontal throughout the travel the suspension would be more linear. At about 80mm into the travel though it starts to ramp up at at 100mm it is ramping up sharply up to the end of the travel. This is to prevent it from bottoming out. It's the linear travel that makes the suspension feel plush.



    The ML, however, is a rising rate suspension (shown by the blue line). The red line though shows how the suspension design is trying to create the feel of a falling rate suspension (more plush) from about 0 to 50mm and starts to rise rapidly past 60mm into the travel. So the ML is a rising rate design but in order to make it feel plush over smaller bumps the suspension leverage ratio is greater below the 50mm mark. (higher leverage ratio makes it easier to compress the shock)

    I don't know if this answers your question. And I might add that my explanation might be corrected by someone more knowledgable than myself but this is how I understand it. To break it down though it would by design look like this:

    Yeti 575 Travel:
    10mm to 100mm = Linear plush travel
    > 100mm into the travel = Ramps up quickly

    Titus Motolite:
    0mm to 50mm = Feels plush due to the leverage ratio overcomming the rising rate.
    60mm and above = Ramps up progressively

  15. #15
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    GEEK ALERT!
    just kidding man..


    Ever plot the Giant's Maestro suspension?
    It wasn't me

  16. #16
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    Quote Originally Posted by Howeler
    GEEK ALERT!
    just kidding man..


    Ever plot the Giant's Maestro suspension?
    Yep, I am a GEEK. That's for sure.

    You can download this free version of the Linkage software and check out all kinds of suspension designs. http://www.bikechecker.com/ Care should be taken though because it will bring out the geek in you as well. Especially when you get the animation to start moving the suspension... too cool...

    Here is a diagram of the 2005 Trance.
    Attached Images Attached Images

  17. #17
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    Quote Originally Posted by iviguy

    Yeti 575 Travel:
    10mm to 100mm = Linear plush travel
    > 100mm into the travel = Ramps up quickly
    What do you make of the blip at the very beggining of the plot?

    I wonder if that's the initial stiffness that you feel with the 575, or if just setting the sag you are already past it.

  18. #18
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    Quote Originally Posted by crashtoomuch
    What do you make of the blip at the very beggining of the plot?

    I wonder if that's the initial stiffness that you feel with the 575, or if just setting the sag you are already past it.
    Yeah, I didn't know how to address that really which is why I didn't mention it. After looking at the program though here's what I come up with.

    25% sag (13.43mm shock compression) = 34mm vertical rear wheel travel (total travel 145mm)

    The "blip" you are talking about is less than 10mm in the travel. Probably more like 5mm at the most so it's well below the 25% sag area.

    At 5mm vertical rear wheel travel = shock compression 2.2mm
    At 10mm vertical rear wheel travel = shock compression 4.3mm

    I think the blip is that breaking point initially where the carbon pivots start to bend and/or the dogbone starts to move. A certain amount of force is needed just to get the dogbone to start moving. I think that's what the blip is but it's below the sag area so it's probably not even an issue.

  19. #19
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    Ivyguy,
    I went to the bikechecker site. The 3D modelling really helps visualise how the parts interact. The data output is also interesting. I do wonder at the accuracy of the program but nevertheless, thank you so much for sharing this with the rest of us.

  20. #20
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    Quote Originally Posted by HYH
    Ivyguy,
    I went to the bikechecker site. The 3D modelling really helps visualise how the parts interact. The data output is also interesting. I do wonder at the accuracy of the program but nevertheless, thank you so much for sharing this with the rest of us.
    I love helping a fellow GEEK...

  21. #21
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    Thanks!

    Quote Originally Posted by iviguy
    LOL... I'll explain as best as I have been able to wrap my mind around it anyway....

    The Force Characteristics graphs show the mm of travel along the horizontal axis. The vertical axis is representative of the amount of force being applied to push the suspension back. Below is directly from the program's manual:




    The Force Characteristics for the 575 basically show that it has a more linear design. A rising rate suspension means that as the shock is compressed further into it's travel it will increase the force to return to normal. All shocks would be rising rate by their design. The further you go into the suspension the harder it is to compress the shock. So by the same token, a falling rate suspension would be opposite. A linear rate suspension is going to be more equal in the force throughout the travel of the suspension.

    So basically what you can see with the 575 forces graph is that because the line is fairly horizontal throughout the travel the suspension would be more linear. At about 80mm into the travel though it starts to ramp up at at 100mm it is ramping up sharply up to the end of the travel. This is to prevent it from bottoming out. It's the linear travel that makes the suspension feel plush.



    The ML, however, is a rising rate suspension (shown by the blue line). The red line though shows how the suspension design is trying to create the feel of a falling rate suspension (more plush) from about 0 to 50mm and starts to rise rapidly past 60mm into the travel. So the ML is a rising rate design but in order to make it feel plush over smaller bumps the suspension leverage ratio is greater below the 50mm mark. (higher leverage ratio makes it easier to compress the shock)

    I don't know if this answers your question. And I might add that my explanation might be corrected by someone more knowledgable than myself but this is how I understand it. To break it down though it would by design look like this:

    Yeti 575 Travel:
    10mm to 100mm = Linear plush travel
    > 100mm into the travel = Ramps up quickly

    Titus Motolite:
    0mm to 50mm = Feels plush due to the leverage ratio overcomming the rising rate.
    60mm and above = Ramps up progressively
    quite clear now.
    cheers
    GB

  22. #22
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    Yeah sweet explanation iviguy!!

  23. #23
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    Quote Originally Posted by crisillo
    Yeah sweet explanation iviguy!!
    See, your starting to get a glimps into my 6+ month obsession over which bike to buy. Looking into all this data and the differences can be mind numbing..... I love breaking things down to understand it but the guys that said just to go out and ride it and make a decision were spot on the money...

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    I have to disagree with some things in this explanation, mostly from a physics standpoint rather than semantics.

    The red line in those graphs is the (inappropriately termed) gradient of the force vs distance curve. This is the derivative of the force curve, ie its slope at that value of travel distance. The higher the red line is at any point, the steeper the blue line points up.

    The blue line is actual force at a given amount of travel distance. This is not the "rate" referred to. The "rate" is the rate of change of force with respect to distance.

    A linear rate suspension's red line would be straight and horizontal. The blue line would be straight and diagonal. Falling rate means the red line is oriented downward, at that point. Falling rate does not mean the blue/force line automatically starts going down; if it is currently going up, it will continue going up more slowly until it peaks and eventually drops. Rising rate means the red line is oriented upwards, at that point, and its effect on the blue line is the opposite of falling rate.

    So if you look at the graphs, they can both be classified in exactly the same way: they start out falling rate, are linear at exactly one point in their respective travels, and then they're both rising rate.

    (reading a calculus book is a prerequisite to trying to argue with anything above this line )

    A more telling graph would be getting the ML and 575 onto the same graph within Linkage, so that they'd both be on the same scale. It'd show the difference in the point at which both bikes switch between falling and rising rate, and show the difference in the steepness of the ramp-up afterwards. It'd also show the difference in bottom-out force between the two bikes (final height of the blue lines).

    To save the suspense, though: the 575's switch point is a little deeper into the travel than the ML's. Makes sense, since the 575 has more travel. The ML has a steeper rate of rise, and more bottom-out force. So the 575 is a more plush over small stuff and has a little less bottom-out resistance built into the frame (it WAS designed for shocks like the RP3 that help a lot with that). The ML can take slightly bigger hits while still being pretty conforming to small bumps. These differences should be pretty obvious just looking at the ML's rear triangle and the 575's longer travel.

    Also, because they really are quite similar in terms of their curves with respect to their travel length, both bikes are equally picky about their sag. Less than ideal air pressure will make either bike more harsh over small stuff and still more likely to bottom out.

    As for the chain growth, the ML is a better design for avoiding it. The difference is huge in terms of percentage; the ML spanks most bikes on the market on that stat (at least while in the big gear ring that Linkage defaults to).

    However, the actual numerical difference is NOT big, look at the numbers. If you blast through all 5.75 inches of the Yeti's travel, you get an unweighted pedal kickback of about half an inch. If you use all your travel, though, you're coasting or jumping, and there are these cool things called freehubs... when you're actually pedalling uphill you're going to be down in the travel range that gives you more around 4 mm of kickback difference between the bikes.

    That's "down in the noise," or something you're not going to notice unless you're trying really hard to notice it--and then it's probably confirmation bias. The benefits of less fatigue from a more plush ride go a long way toward cancelling out any real efficiency difference.

    My bottom line for all of this: the bikes have really similar suspension characteristics. Anyone comparing these two bikes should NOT be thinking in terms of single pivot or 4-bar, they should be thinking whether they want a little more squish or a bike that's a little stiffer and can take bigger hits at the expense of a little bit of plushness. That, along with everything else that makes you favor one bike over the other: fit, perceived quality, peer pressure, paint color (or in the ML's case, how easily the paint color goes away), random fixation, etc.

    The geometries are pretty similar between them, so any time someone loves one and hates the other I'm very suspicious that one wasn't set up right for the rider.

  25. #25
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    Calculus is fine

    Quote Originally Posted by Suicider
    I have to disagree with some things in this explanation, mostly from a physics standpoint rather than semantics.

    The red line in those graphs is the (inappropriately termed) gradient of the force vs distance curve. This is the derivative of the force curve, ie its slope at that value of travel distance. The higher the red line is at any point, the steeper the blue line points up.

    The blue line is actual force at a given amount of travel distance. This is not the "rate" referred to. The "rate" is the rate of change of force with respect to distance.

    A linear rate suspension's red line would be straight and horizontal. The blue line would be straight and diagonal. Falling rate means the red line is oriented downward, at that point. Falling rate does not mean the blue/force line automatically starts going down; if it is currently going up, it will continue going up more slowly until it peaks and eventually drops. Rising rate means the red line is oriented upwards, at that point, and its effect on the blue line is the opposite of falling rate.

    So if you look at the graphs, they can both be classified in exactly the same way: they start out falling rate, are linear at exactly one point in their respective travels, and then they're both rising rate.

    (reading a calculus book is a prerequisite to trying to argue with anything above this line )

    A more telling graph would be getting the ML and 575 onto the same graph within Linkage, so that they'd both be on the same scale. It'd show the difference in the point at which both bikes switch between falling and rising rate, and show the difference in the steepness of the ramp-up afterwards. It'd also show the difference in bottom-out force between the two bikes (final height of the blue lines).

    To save the suspense, though: the 575's switch point is a little deeper into the travel than the ML's. Makes sense, since the 575 has more travel. The ML has a steeper rate of rise, and more bottom-out force. So the 575 is a more plush over small stuff and has a little less bottom-out resistance built into the frame (it WAS designed for shocks like the RP3 that help a lot with that). The ML can take slightly bigger hits while still being pretty conforming to small bumps. These differences should be pretty obvious just looking at the ML's rear triangle and the 575's longer travel.

    Also, because they really are quite similar in terms of their curves with respect to their travel length, both bikes are equally picky about their sag. Less than ideal air pressure will make either bike more harsh over small stuff and still more likely to bottom out.

    As for the chain growth, the ML is a better design for avoiding it. The difference is huge in terms of percentage; the ML spanks most bikes on the market on that stat (at least while in the big gear ring that Linkage defaults to).

    However, the actual numerical difference is NOT big, look at the numbers. If you blast through all 5.75 inches of the Yeti's travel, you get an unweighted pedal kickback of about half an inch. If you use all your travel, though, you're coasting or jumping, and there are these cool things called freehubs... when you're actually pedalling uphill you're going to be down in the travel range that gives you more around 4 mm of kickback difference between the bikes.

    That's "down in the noise," or something you're not going to notice unless you're trying really hard to notice it--and then it's probably confirmation bias. The benefits of less fatigue from a more plush ride go a long way toward cancelling out any real efficiency difference.

    My bottom line for all of this: the bikes have really similar suspension characteristics. Anyone comparing these two bikes should NOT be thinking in terms of single pivot or 4-bar, they should be thinking whether they want a little more squish or a bike that's a little stiffer and can take bigger hits at the expense of a little bit of plushness. That, along with everything else that makes you favor one bike over the other: fit, perceived quality, peer pressure, paint color (or in the ML's case, how easily the paint color goes away), random fixation, etc.

    The geometries are pretty similar between them, so any time someone loves one and hates the other I'm very suspicious that one wasn't set up right for the rider.
    It just that my eyes view the graphs a little different than yours.
    If both bikes are saged arround 30mm, than for the first unit of force applied (not sure what the units are) the Yeti will "travel" vertically ~ 50mm where the ML ~ 20mm. This "trend" is soon reversed if further force applied as the 575 "resists" bottom out situation.
    I don't know if this is good, bad or how it compares but it does not seem very similar to me.
    I sure want to demo an ML and see how it handles the trails I ride. Numbers graphs and theory on paper does not always translate to feel.
    This thread is nevertheless very interesting and constructive.
    Cheers
    GB

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