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  1. #1
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    any mechanical engineers in the house, got a ? for you

    im looking at the Reign 2 and the Pitch Pro, what do you see in these 2 designs that you would considered cons, even if its insanely slight. and im talking about jumping, reliability, active suspension, flex, etc.. anything you can think of. i really want to dissect these bikes

    thanks




  2. #2
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    One's black and the other is brown. Black bikes last longer due to the molecular structure of black pain, ie; KITT.

  3. #3
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    Variations in the welding of each joint are far greater than the design that is apparent from looking at two pictures. There is nothing inherently wrong with either design from an engineering standpoint (believe it or not, I have a ME degree). Just ride them and go with the one you fit best one and the one you like to ride most. The companies did their job, they're both sound.
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  4. #4
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    The black frame is a Giant built frame with "Giant" decals, and the brown frame is a Giant built frame with "Specialized" decals.

  5. #5
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    I do have opinion about these 2 frames pros and cons. As I own the Reign and rode pitch a few times back to back. Unfortunately, I don't have ME Degree yet. Can't offer expert in depth analysis.

  6. #6
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    the giaant has the maestro supension

    both are faux bar types , but the maestro moves one of the pivot points closer to the others, making the reponce llinear , an inprovoing pedaling, cause it a takes a lil more force to "break" the suspensions geometry, it like the suspension has propedal built in, the wheel also moves almost vertically.

    the specialized has a more standard faux bar desing, there the wheel moves in a curve to wards the seat. but has the more familiar reponse,

    the specialized desing will be more responsive, to small bumps an be active all the time

    the giants will be less prone to pedal bob, and give you a more linear response once the suspension is active
    2009 Giant Yukon FX

  7. #7
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    Quote Originally Posted by Brujo
    the giaant has the maestro supension

    both are faux bar types , but the maestro moves one of the pivot points closer to the others, making the reponce llinear , an inprovoing pedaling, cause it a takes a lil more force to "break" the suspensions geometry, it like the suspension has propedal built in, the wheel also moves almost vertically.

    the specialized has a more standard faux bar desing, there the wheel moves in a curve to wards the seat. but has the more familiar reponse,

    the specialized desing will be more responsive, to small bumps an be active all the time

    the giants will be less prone to pedal bob, and give you a more linear response once the suspension is active
    I don't know about this, since cycling suspension uses some different terms than engineering when defining linkage systems, but I'm pretty sure that's not a correct assessment of those suspensions.

    Specialized is a four bar, not a "faux" bar. There is a pivot point between the chainstay and the rear wheel, allowing the rear wheel path to be controlled by the other links in the system.

    and Maestro is a similar system to a VPP, where the wheel path is controlled by a carefully planned movement of various links to determine instant centers and such, but it is not a "faux" bar either due to the link placed between the BB pivot and the rear wheel pivot.

    Again, I'm not a suspension terminology pro, so someone correct me as needed. And xomeone help me out who's taken machine design more recently than I, but aren't all these link actuated shock suspension systems like 5 or 6 bar systems anyway? This has bothered me for a while and it would be good to get someone else's opinion on it.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  8. #8
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    Quote Originally Posted by mimi1885
    I do have opinion about these 2 frames pros and cons. As I own the Reign and rode pitch a few times back to back. Unfortunately, I don't have ME Degree yet. Can't offer expert in depth analysis.
    ah man, id didnt mean to cut non ME out of this discussion, just trying to get their attention. please, tell us what you think, i want everyones opinions!

    sorry if i offended everyone

  9. #9
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    i dont know how much this will help, i havent read it all yet but i just came across this yesterday

    http://www.mbaction.com/me2/dirmod.a...273868DD20362A

  10. #10
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    Expect the giant to pedal a little better. The specialized may be a little more plush though. They both rock. Get the one that looks/feels best.

    Oh and the black paint on the giant has a denser carbon molecular bond structure (somewhat similar to a graphene bond. Think about it as a 3d graphene bond. This puts its strength close to diamond with weight levels of carbon fiber. As a result its about 15% stronger than the specialized. It also helps alleviate frame flex by about -10%

    Hey at least I was half serious!

  11. #11
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    Quote Originally Posted by Dirt Bringer
    Expect the giant to pedal a little better. The specialized may be a little more plush though. They both rock. Get the one that looks/feels best.

    Oh and the black paint on the giant has a denser carbon molecular bond structure (somewhat similar to a graphene bond. Think about it as a 3d graphene bond. This puts its strength close to diamond with weight levels of carbon fiber. As a result its about 15% stronger than the specialized. It also helps alleviate frame flex by about -10%

    Hey at least I was half serious!
    lol, hmm, that sounded like you knew what you were talking about

  12. #12
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    yeah most of the suspension i work with is machinery, not so hip to bike suspension terms
    2009 Giant Yukon FX

  13. #13
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    damn brujo, you butchered that one! spec invented the silly marketing term "faux bar" to downplay everyone elses bikes and prop up their FSR/horst link design. the pitch is specs typical horst link rear suspension.

    the giant is a dual short link bike. this will always be active, spec wont.

    you really dont want to dig into the internet/on paper junk about the bikes. go ride them, thats what really counts. if the spec rides better for you, buy the spec! forget about everything else and all the technical details.. the only thing that matters is how the bike rides on the trail.

  14. #14
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    Thanks for the invitation Nauc

    I was not offended or trying to be a smart a$$. You had a very specific questions about the 2 bikes and want to get specific answers. I respect that.

    I like the Maestro design, dual-short link seems to fit the current bill of trail riding. I own 2 first gen reign I just mess around with them as I put dual crown fork on one of them. The only thing I don't like about my reign is the weight. It's about 8.5lbs, fortunately, the new ones are much lighter. I just rode the Reign X1 last week and it was very impressive how a 32lbs bike can climb with zest! and descend like a mad man running with the hair on fire.

    I also like the Pitch. It's not a snappy climber but you can sense the generous traction on the technical climb, much like an Ellsworth Moment. I rode these 2 bikes back to back last week both were medium. I usually ride a small, but I do own medium bikes as well. The Reign fit me just fine with ample stand over room, pitch is a bit larger though the S.O. was never an issue. I feel that the Reign shorter cockpit is a better fit for me.

    It's given that both bikes are winners, IMO RX strength is Climb/Descend, but the Pitch definitely shine in the middle. It corners really well and accelerate well. Take it with the grain of salt as the RX has almost 1" more travel. You should Demo both it's hard to be disappointed as both bikes offer a lot of value for the money. If you do decide to get the RX I'd suggest the double ring.

  15. #15
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    thanks and i plan to ride them both but i want to have ammo going in. if someone says that they dont like something about either of the bikes, i will check into it myself when i demo them

    thanks all

  16. #16
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    You can't go wrong with either. Those are two good companies that have done their engineering work. Everyone has their personal preference and you just have to find what you like. I personally don't like Giant bikes, they get squeaky too fast, but that doesn't mean they make a worse/better bike than anyone else. Buy the one you like to ride the most and to hell with what company makes it!
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  17. #17
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    Quote Originally Posted by Dirt Bringer
    Oh and the black paint on the giant has a denser carbon molecular bond structure (somewhat similar to a graphene bond. Think about it as a 3d graphene bond. This puts its strength close to diamond with weight levels of carbon fiber. As a result its about 15% stronger than the specialized. It also helps alleviate frame flex by about -10%

    If you want to pretend to sound like a MECHANICAL engineer, you have to talk more about moments, forces, vibrations, welding, machining, stress concentration factors, leverage ratios, fatigue, axle path, finite element analysis, and less about molecular bond structures.
    When under pressure, your level of performance will sink to your level of preparation.

  18. #18
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    Quote Originally Posted by rkj__
    If you want to pretend to sound like a MECHANICAL engineer, you have to talk more about moments, forces, vibrations, welding, machining, stress concentration factors, leverage ratios, fatigue, axle path, finite element analysis, and less about molecular bond structures.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  19. #19
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    Quote Originally Posted by nauc
    lol, hmm, that sounded like you knew what you were talking about
    Lol. Majoring in the sciences also gives you an unofficial degree in speaking bs lol.
    To answer your question, Ive done alot of research (meaning reading other peoples research) about these designs, and here is what Ive found. They are both a form of a floating pivot point, in a way. The pivot points are below the axle and create somewhat of a 3d swing in the swingarm rather than a semi-linear or curved swing on a single or faux (4 pivot) point suspension system, (which have the second pivot ABOVE the axle, this is how you tell the difference). They both come out of automotive research and engineering. This of course dosent mean much except on paper. In real world applications, simplified, the effects of each should be this (and nobody crucify me here, this is what the effects SHOULD be, not what they always ARE): The specialized fsr system should mostly resist suspension movement (bobbing) for good pedaling, and eliminate brake jack (locking of the rear suspension under braking). It is also fully active and should be very plush and responsive, similar to a single pivot without pathetic levels of bobbing. The system has been repatented over a period of about 15 or 20 years now, it was originally bought from rocky mountain cycles and I believe its designer is John Whyte, a formula 1 suspension engineer.

    Now the giant system. The giant system is based off of a system about 10 years old now, but which only reached refinement about 5 or 6 years ago. It was always very good though. It is based off the standard floating pivot point system, a system giant (like santa cruz) managed to patent (under certain geometries) and which is very, very, very good. It is based on a system that creates a suspension travel path that first floats back and then up and forward. The purpose of this is to lengthen chainlength and use the drivetrain to prevent suspension movement. Use of the change in suspension curve is also used to create varying shock compression rates at different stages of travel. Different companies approach this differently. Some set their bikes up for great sensitivity to small bumps at first part of stroke (like roots small rocks etc.) and tolerate a small amount of constant suspension movement (very small amount) after which as the suspension compresses it ramps up in rate rapidly. This causes the suspension to cease its compression under pedaling and better handle large impacts. The giant system should perform specifically as follows however (as you can see systems deviate from one to another): The giant will pedal incredibly well, better than the specialized overall. However, it will be slightly less plush, at least at the first stroke of travel (very small bumps). Some systems such as this experience squat under braking. The giant experiences very little, if any, of this. The system will be fully active like the specialized.

    Overall, the giant has a slightly better suspension system for me, and has what is arguably the best floating pivot point system on the market. However, some people prefer the traits of the specialized for its high sensitivity. It is really up to use and personal preference in the end. Both systems are very good, and both companies have done such a good job with their bikes that flex and weight are really non-issues between the two.

  20. #20
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    Quote Originally Posted by Dirt Bringer
    Lol. Majoring in the sciences also gives you an unofficial degree in speaking bs lol.
    To answer your question, Ive done alot of research (meaning reading other peoples research) about these designs, and here is what Ive found. They are both a form of a floating pivot point, in a way. The pivot points are below the axle and create somewhat of a 3d swing in the swingarm rather than a semi-linear or curved swing on a single or faux (4 pivot) point suspension system, (which have the second pivot ABOVE the axle, this is how you tell the difference). They both come out of automotive research and engineering. This of course dosent mean much except on paper. In real world applications, simplified, the effects of each should be this (and nobody crucify me here, this is what the effects SHOULD be, not what they always ARE): The specialized fsr system should mostly resist suspension movement (bobbing) for good pedaling, and eliminate brake jack (locking of the rear suspension under braking). It is also fully active and should be very plush and responsive, similar to a single pivot without pathetic levels of bobbing. The system has been repatented over a period of about 15 or 20 years now, it was originally bought from rocky mountain cycles and I believe its designer is John Whyte, a formula 1 suspension engineer.

    Now the giant system. The giant system is based off of a system about 10 years old now, but which only reached refinement about 5 or 6 years ago. It was always very good though. It is based off the standard floating pivot point system, a system giant (like santa cruz) managed to patent (under certain geometries) and which is very, very, very good. It is based on a system that creates a suspension travel path that first floats back and then up and forward. The purpose of this is to lengthen chainlength and use the drivetrain to prevent suspension movement. Use of the change in suspension curve is also used to create varying shock compression rates at different stages of travel. Different companies approach this differently. Some set their bikes up for great sensitivity to small bumps at first part of stroke (like roots small rocks etc.) and tolerate a small amount of constant suspension movement (very small amount) after which as the suspension compresses it ramps up in rate rapidly. This causes the suspension to cease its compression under pedaling and better handle large impacts. The giant system should perform specifically as follows however (as you can see systems deviate from one to another): The giant will pedal incredibly well, better than the specialized overall. However, it will be slightly less plush, at least at the first stroke of travel (very small bumps). Some systems such as this experience squat under braking. The giant experiences very little, if any, of this. The system will be fully active like the specialized.

    Overall, the giant has a slightly better suspension system for me, and has what is arguably the best floating pivot point system on the market. However, some people prefer the traits of the specialized for its high sensitivity. It is really up to use and personal preference in the end. Both systems are very good, and both companies have done such a good job with their bikes that flex and weight are really non-issues between the two.
    awesome! thanks!

  21. #21
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    Quote Originally Posted by rkj__
    If you want to pretend to sound like a MECHANICAL engineer, you have to talk more about moments, forces, vibrations, welding, machining, stress concentration factors, leverage ratios, fatigue, axle path, finite element analysis, and less about molecular bond structures.
    Tell that to my chemistry teacher. And yes I agree your right. 2 semesters of chemistry in a row have a very negative impact on the human brain. Ill get back to normal in a year or so. lol.

  22. #22
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    Quote Originally Posted by One Pivot
    the giant is a dual short link bike. this will always be active, spec wont.
    I'm no suspension expert or ME by any means, but from my personal experience with both.... the horst link is more freely active than the maestro (at least it feels that way)....more bobbing, more squatting, and more need for propedal to counteract this. The upside to this is a slightly plusher feeling ride.

  23. #23
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    whats squatting

  24. #24
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    Quote Originally Posted by d365
    I'm no suspension expert or ME by any means, but from my personal experience with both.... the horst link is more freely active than the maestro (at least it feels that way)....more bobbing, more squatting, and more need for propedal to counteract this. The upside to this is a slightly plusher feeling ride.
    Your right. It is. I think hes confusing fsr with faux pivot systems, which are not fully active but look almost identical. The main difference is the pivot point ABOVE the axle rather than below and in front. Squatting is when brake action makes the suspension compress slightly and the back of the bike dips. This does not make it inactive but it is still annoying. The giant shouldnt experience this. Certain floating pivot point systems however do.

  25. #25
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    do you guys take those little suspension differences into account when choosing a frame?

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    Quote Originally Posted by Dictatorsaurus
    do you guys take those little suspension differences into account when choosing a frame?
    Yes, certainly.
    When under pressure, your level of performance will sink to your level of preparation.

  27. #27
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    Quote Originally Posted by Dirt Bringer
    Squatting is when brake action makes the suspension compress slightly and the back of the bike dips. This does not make it inactive but it is still annoying. The giant shouldnt experience this. Certain floating pivot point systems however do.
    I don't think squat is limited to braking, though. It was most noticeable to me when accelerating, or grinding out hard, steep climbs. There is some relationship between the amount of force applied to the pedals, and the amount of squat you get.... not to be confused with bobbing.

    Squat was my biggest peeve about my Stumpy.

  28. #28
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    Quote Originally Posted by Dictatorsaurus
    do you guys take those little suspension differences into account when choosing a frame?
    im taking everything i and others can think of, into account. my azz is broke, so it will probably be a long time before i get a new bike, so i gotta make this one really count

  29. #29
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    We all do, but in the end there's no one bike that do it all. I can't tell you exactly on the engineering side of which one is better. One thing I know for a fact, you can flip a coin, spin the bottle, or roll the dice for your pick between these 2 bikes. You'll just love it.

  30. #30
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    Quote Originally Posted by Dirt Bringer
    Your right. It is. I think hes confusing fsr with faux pivot systems, which are not fully active but look almost identical. The main difference is the pivot point ABOVE the axle rather than below and in front. Squatting is when brake action makes the suspension compress slightly and the back of the bike dips. This does not make it inactive but it is still annoying. The giant shouldnt experience this. Certain floating pivot point systems however do.
    fsr was made to improve braking performance, its still going to stiffen up a little. same with pedaling, if its bobbing, thats travel you otherwise could be using to absorb the trail.. less active. its physically moving more, but not in the way its supposed to. less actively absorbs the trail. maestro will stay more active under both condition.

    even single pivots dont excessively compress the rear suspension, it just stiffens it and you can lose a bit of braking traction. your front is taking care of the majority of actual stopping, the rear loosens up as you ease off the brake. the negative aspect of this is kinda overblown.. most riders dont even report noticing it (i do a bit, but its no where near a deal breaker).

    does it really matter? i dont think so. the least active you can possibly make your rear end would be having a hardtail.. that would be the extreme far end of "bad" in terms of active rear performance, and hardtail riders seem to do pretty well either way. if you cant clear it on a FSR bike, you wont clear it on a maestro bike.

    suspension bob can be largely mitigated by technique, unless you're the kind of rider who just has to mash up everything.. in which case your choice gets pretty easy on the test ride.

    if you *really* want to make your purchase count, buy the bike that rides better. forget everything else. if a bike is in every single way better on paper, but you think it rides like ass, buying it would be a waste of your money! its great to educate yourself on the matter, but dont put all your purchasing decision weight on technical information that you might not even notice.

    for example, the new enduro pedals amazing! i couldnt feel it bobbing even remotely, and that was with an under pressurized shock with no propedal. it felt great, it bobbed less than the blur LT i rode, which technically should have pedaled better.

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    Quote Originally Posted by One Pivot
    fsr was made to improve braking performance, its still going to stiffen up a little. same with pedaling, if its bobbing, thats travel you otherwise could be using to absorb the trail.. less active. its physically moving more, but not in the way its supposed to. less actively absorbs the trail. maestro will stay more active under both condition.

    even single pivots dont excessively compress the rear suspension, it just stiffens it and you can lose a bit of braking traction. your front is taking care of the majority of actual stopping, the rear loosens up as you ease off the brake. the negative aspect of this is kinda overblown.. most riders dont even report noticing it (i do a bit, but its no where near a deal breaker).

    does it really matter? i dont think so. the least active you can possibly make your rear end would be having a hardtail.. that would be the extreme far end of "bad" in terms of active rear performance, and hardtail riders seem to do pretty well either way. if you cant clear it on a FSR bike, you wont clear it on a maestro bike.

    suspension bob can be largely mitigated by technique, unless you're the kind of rider who just has to mash up everything.. in which case your choice gets pretty easy on the test ride.

    if you *really* want to make your purchase count, buy the bike that rides better. forget everything else. if a bike is in every single way better on paper, but you think it rides like ass, buying it would be a waste of your money! its great to educate yourself on the matter, but dont put all your purchasing decision weight on technical information that you might not even notice.

    for example, the new enduro pedals amazing! i couldnt feel it bobbing even remotely, and that was with an under pressurized shock with no propedal. it felt great, it bobbed less than the blur LT i rode, which technically should have pedaled better.
    Ya thats pretty much my point. Well worded though. And you have a point. I know all this because Im studying engineering and find it fascinating, not because it makes a difference to my riding. I ride a hardtail, and do quite well if I may say so myself. I know a dude at the trails that rides a rigid, and can beat anyone else on the trails, me included, fairly easily. These are midwest trails, not too mellow. Oops got off topic. Point is you dont need to worry too much about the suspension to have a great riding bike. It really comes down to which feels better. That said I was testing out my friends new fsr today, and I must say, that pothole sure felt alot smaller with 5 inches of travel at the back... Suspension bob does not amuse me however.

  32. #32
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    Quote Originally Posted by nauc
    im taking everything i and others can think of, into account. my azz is broke, so it will probably be a long time before i get a new bike, so i gotta make this one really count
    Parameters to consider while choosing a full suspension bike:
    (from the most important to the less important)

    1. It has to look nice/cool (by far the most important factor)
    2. Fit
    3. Geometry and build quality for the intended use.
    4. Components in general.
    .
    .
    .
    .
    8. Resale value....
    9. All other factors to consider.
    .
    .
    100. Suspension type.

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    Here's a quick sketch just done from tracing the photos by eye.

    Those photos aren't at the same scale - but if you look long enough at the struts, pivots and forces in your mind's eye you may get an intuition of how they will each act.


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    my first impression is the red one would be better because the pivot is more aligned with the seat and bb, which would seem really strong

    tho the green one is more vertical so it seems it would be more active

    tho i have no idea what im talking about, these are just some first impressions

  35. #35
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    any other thoughts

    thanks

  36. #36
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    Quote Originally Posted by nauc
    my first impression is the red one would be better because the pivot is more aligned with the seat and bb, which would seem really strong

    tho the green one is more vertical so it seems it would be more active

    tho i have no idea what im talking about, these are just some first impressions
    Dude, those drawings tell you exactly nothing, except that the person who drew them knows even less if they think that an eyeballed sketch will tell them anything about how the suspension will perform.
    Dad is sad.
    Very, very sad.
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  37. #37
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    Pick up the latest issue of Mountain Bike Action. Yes, I know alot of people dont like them and I know why, but in their latest issue they have a very in depth and long article about all the different kinds of suspension systems made. VERY informative. It will answer anything we didnt.

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    Quote Originally Posted by Dad Man Walking
    Dude, those drawings tell you exactly nothing, except that the person who drew them knows even less if they think that an eyeballed sketch will tell them anything about how the suspension will perform.
    Well the drawings were traced from the photos that were given - as that was the only information presented.

    Think of an experienced carpenter eyeballing a beam and the forces that will be applied to it, and intuitively picking the correctly sized beam - the same principle is at work here - the principle of intuition.

    I just thought I'd try get this across - intuition is the primary principle in science and engineering although many people today think their computer will give them all the answers. It won't - first, you have an intuition, then you prototype, test, measure, or investigate etc.

    Especially, in bike design, it is intuition that tells somebody a design might work well, then they go and test it with the FE programmes or whatever. Still, their FE programmes will only tell them so much, the real telling will be in the riding of it.

    I said in my post above that people MAY get an intuition of how the two designs above may ride from clearly seeing the arrangement of the struts and pivot points. If someone has ridden a lot of bikes, taken in the design of them, sure they might be able to tell from a diagram. Obviously, they'll be able to tell much better from actually riding the bikes. We can see in the above diagrams that the designs are quite close. So, the riding experience will likely be quite close also?

    The primary point is that the hard engineering analysis part is fairly obvious - low centre of gravity, weight, pedal forces absorbed by suspension as little as possible, active suspension paths, wheel base etc. But the part that sets a bike apart is a little bit of magic and art. Computers and analysis won't reveal this.

  39. #39
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    Still, those drawings tell you nothing.

    Quote Originally Posted by ronank
    Well the drawings were traced from the photos that were given - as that was the only information presented.

    Think of an experienced carpenter eyeballing a beam and the forces that will be applied to it, and intuitively picking the correctly sized beam - the same principle is at work here - the principle of intuition.

    I just thought I'd try get this across - intuition is the primary principle in science and engineering although many people today think their computer will give them all the answers. It won't - first, you have an intuition, then you prototype, test, measure, or investigate etc.

    Especially, in bike design, it is intuition that tells somebody a design might work well, then they go and test it with the FE programmes or whatever. Still, their FE programmes will only tell them so much, the real telling will be in the riding of it.

    I said in my post above that people MAY get an intuition of how the two designs above may ride from clearly seeing the arrangement of the struts and pivot points. If someone has ridden a lot of bikes, taken in the design of them, sure they might be able to tell from a diagram. Obviously, they'll be able to tell much better from actually riding the bikes. We can see in the above diagrams that the designs are quite close. So, the riding experience will likely be quite close also?

    The primary point is that the hard engineering analysis part is fairly obvious - low centre of gravity, weight, pedal forces absorbed by suspension as little as possible, active suspension paths, wheel base etc. But the part that sets a bike apart is a little bit of magic and art. Computers and analysis won't reveal this.
    For two main reasons:

    1. The obvious reason: Pivot point placement. Maestro and FSR have a completely different pivot arrangement. Look it up and you will see that the Maestro has an extra lower link and the fsr has a pivot on the chainstay near the axle. those drawings don't show the pivots correctly.
    2. Generally,Two designs may look the same but can still perform different just because of a slight difference in the relations of the swingarm components. You may not be able to notice such difference just by looking at it. The opposite is also possible: Two different designs can be engineered to perform quite the same.

  40. #40
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    Quote Originally Posted by ronank
    Well the drawings were traced from the photos that were given - as that was the only information presented.

    Think of an experienced carpenter eyeballing a beam and the forces that will be applied to it, and intuitively picking the correctly sized beam - the same principle is at work here - the principle of intuition.

    I just thought I'd try get this across - intuition is the primary principle in science and engineering although many people today think their computer will give them all the answers. It won't - first, you have an intuition, then you prototype, test, measure, or investigate etc.
    Wow, it's rare that you get a candidate for "Most inane post of the week" right off the bat. You really should have stopped your explanation of the two designs at "people MAY get an intuition of how the two designs above may ride from clearly seeing the arrangement of the struts and pivot points". Anything else you said was so wrong it made me angry. So I'm going to take a deep breath and try and be nice with my own inane response.

    Intuition is not the core of science and engineering, and bikes are not designed by magically guessing what might be a good way to put pivots. Bikes are designed through a generally rigorous process of iteration. If you think Santa Cruz just threw some pivots on a bike hoped it worked and released the bike to market, you're mistaken. It takes small design changes to produce whatever bike you're riding now. Whether that's a history of changes of geometry over the past 15 years, or small tweaks of millimeters of pivot location, your bike was not gifted from heaven.

    I promise you that scientists and engineers are not running around saying "um, yeah that car probably won't fold in half when it hits a pothole, the thing looks strong" or "gee, a big asteroid hasn't hit the earth in a long time, we probably don't have to worry about that one either". Science is backed by process, repeatability, and careful calculation.

    You need to get the tools needed to do analysis on suspension designs. http://www.bikechecker.com/demo.phtml Linkage is a cool program where you can see some designs and how they compare in wheel path, shock leverage, flux capacitor length, and so on. So go check it out, play with it, and start learning how to design a bike with more than just intuition, which is just a woman's razor anyway.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  41. #41
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    I agree that most if not all designs START with intuition, and then the process is to prototype (physical, graphical, etc.), test, then revise the design until the design objectives are met. Without intuition (which comes from knowledge and experience), there can be no design to even start the process.

    You see an opportunity for improvement, devise a mechanism that should address the problem (this is the intuitive/creative part), calculate the stresses, prototype, then test, test, test.

    In regards to a the earlier statement:

    Think of an experienced carpenter eyeballing a beam and the forces that will be applied to it, and intuitively picking the correctly sized beam

    This is not a good example. Carpenters work from blueprints. They have the experience of having used a beam that big before, but not the knowledge of why (stress calculations) it was used.

  42. #42
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    ronank is also ignoring the second short link hidden behind the bottom bracket.
    as his drawing stands the top of the swingarm would rip itself off while travelling in the arc the top link demands.

    for the record you can't "eyeball" forces that are being applied to a beam.
    you can observe (or eyeball) the effect the forces have on the material.
    angle of deflection over the length of the beam, that sort of thing.
    but force is... ahem... FORCE.
    but you don't see the forces involved, you don't get little sparkles along the length of your board where it's being strained past it's point of elastic deformation.

    anyone who tells you they can "eyeball" the forces involved is lying.
    what they're doing is GUESSING that MAYBE the amount of force COULD POSSIBLY be within a range that corresponds to "that board I saw that time, so let's use one of those".
    problem is, they're assuming that the factors that they can SEE, are the only factors they need to take into account...
    carpenters like that end up with homeowner lawsuits on their hands.


    *dusting off the old mental textbooks*


    regarding the OP: which one's got better hubs/bottom bracket?
    I REALLY feel that while there will be differences in ride quality, overall, both are really well desigend bikes. so look past the frame designs to what'll keep you off the bike.
    repacking hub bearings, chunky bb, headset.
    the rolling surfaces drag you down and the pivot bearings can make a good suspension design feel like crap.
    ask the LBS who's running better seals/better quality bearings on those parts because the drivetrain and brakes will probably be fairly similar.
    If steel is real then aluminium is supercallafragiliniun!

  43. #43
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    Quote Originally Posted by zebrahum
    Bikes are designed through a generally rigorous process of iteration....
    There'd be fairly infinite iterations to go through if you didn't have intuition to guide you in the right direction; guide you towards where the problems might lie; guide you towards the hunches that might solve those problems etc.

    As a poster above says, it's the first step in any design - and the reason the best bike designs usually come from avid bike riders themselves or close collaborations with bike riders.

  44. #44
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    ronank, you're on some crazy rant that doesnt make sense. the guys at spec and giant arent just guessing how to setup frames, and looking at those drawings tells nobody anything.

  45. #45
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    As an Electrical Engineer I could look at circuits and designs all day and anything I come up with is simply "a guess". Without proper calculations and testing any design is bound to fail.

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