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  1. #1
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    Fox 34 vs Rock Shox stiffness, tested

    After all specualtion about the stiifness of the 34 mm stanchions vs 32 opposed to 15 mm vs 20 TA there is finally some data.
    From Bike Magazin (Germ) dec. 2011.

    The answer is... both.
    The bigger stanchions do give the Fox an edge in braking stiffness, the bigger axle on the Rock Shox nudges out the smaller one in torsion:

    Fox 34 float 140 mm travel :
    2006 g
    torsion 24.8 Nm/degr
    brake stiffness 232.2 Nm/Degr
    Revelation XX 137 mm travel
    1885 g
    torsion: 27.5 Nm/degr
    brake stiffn.: 204.7 Nm/degr.

  2. #2
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    what does this actually translate to "in-the-field" however ?

    both forks are on my radar currently.......

  3. #3
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    As an engineer myself, I can't help but wonder about other variables and their effect to the end user (rider). For instance, the wheels (each part [hub, spoke, rim] and as a whole), tires, and their interface (wheel width/tire pressure/sidewall stiffness...etc), rider weight, head tube/frame stiffness..etc. All these variables could possibly have more effect on the what the rider feels over the stiffness of a fork.

    I like seeing data, but unless every variable is accounted for the data is useless. It's basic scientific rules of testing. None-the-less thanks for posting this info
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  4. #4
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    Quote Originally Posted by bquinn View Post
    As an engineer myself, I can't help but wonder about other variables and their effect to the end user (rider). For instance, the wheels (each part [hub, spoke, rim] and as a whole), tires, and their interface (wheel width/tire pressure/sidewall stiffness...etc), rider weight, head tube/frame stiffness..etc. All these variables could possibly have more effect on the what the rider feels over the stiffness of a fork.

    I like seeing data, but unless every variable is accounted for the data is useless. It's basic scientific rules of testing. None-the-less thanks for posting this info
    I am not an engineer but I don't see what you are saying. I would like to see the methodology of the test but knowing German testing, I'll bet that the forks are measured in a test jig sans wheels. It is simple to measure how much twist and fore/aft flex there is with a given force. Variables are non existent.
    The trouble with having an open mind is that people will insist on trying to put things in it.

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    This data is far from useless. It shows that given equal wheels and tires, the Fox will have superior fore-and-aft (braking) stiffness and the Rockshock will have better lateral stiffness.

    So the RS is about 10% stiffer in torsion (steering accuracy) and the Fox is about 15% stiffer in braking.

    Cool info, thanks for posting!
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    Interesting to read, I donít think this says much about 32/34mm or 15/20mm though. The least torsionaly stiff fork i have ever owned had a 24mm axle. The stiffest for/aft fork Iíve ever owned had 32mm stanchions and Iíve owned 2 forks with 40 mm stanchions. Crown design has alot to do with these characteristics, Iíve bent crowns on a couple of forks over the years and the stanchions remained strait as new.

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    steep fast and loose :)
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    as i said - how does this translate in use - i AM an engineer and value the data offered but wonder how much is actually felt by the end-user.......?

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    Quote Originally Posted by The_Lecht_Rocks View Post
    as i said - how does this translate in use - i AM an engineer and value the data offered but wonder how much is actually felt by the end-user.......?
    what "end user feeling" scale do you want the results in?

    seriously, as an engineer you should understand that how an engineered product is subjectively interpreted by individuals is neither quantifiable nor predictable in specific terms.
    Last edited by meltingfeather; 12-05-2011 at 10:47 AM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  9. #9
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    Quote Originally Posted by bquinn View Post
    As an engineer myself, I can't help but wonder about other variables and their effect to the end user (rider). For instance, the wheels (each part [hub, spoke, rim] and as a whole), tires, and their interface (wheel width/tire pressure/sidewall stiffness...etc), rider weight, head tube/frame stiffness..etc. All these variables could possibly have more effect on the what the rider feels over the stiffness of a fork.

    I like seeing data, but unless every variable is accounted for the data is useless. It's basic scientific rules of testing. None-the-less thanks for posting this info
    what you propose is impossible, and what you are saying is that all data is useless.
    every variable accounted for? is that a joke?
    how on earth would you account for the variables between individual interpretations (the "rider feel")?
    that said... you can assume all else equal for these comparisons. if you did the testing on a whole-bike basis (ignoring the "all variables" fatal shot imparted by trying to predict what individuals will feel), by your own argument the data would be useless to anyone with a different bike set-up. the testing is unitized to comopare individual compoents for a reason.
    and you're an engineer?
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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    Quote Originally Posted by kosmo View Post
    This data is far from useless. It shows that given equal wheels and tires, the Fox will have superior fore-and-aft (braking) stiffness and the Rockshock will have better lateral stiffness.

    So the RS is about 10% stiffer in torsion (steering accuracy) and the Fox is about 15% stiffer in braking.

    Cool info, thanks for posting!
    regarding 'equal wheels'---equal, other than the fact that one wheel would be using a hub configured for 20 mm. but I agree with your point.

    thanks Tjaard for posting. I've said it before and I'll say it again--it's sad that US magazines rarely bother making basic engr measurements such as the ones routinely made in the German bike mags.

    bquinn, re: how engineering analyses work. in my job, we routinely try to 'package' all the variables into one large predictive model, but we realize that this effort is often an endless search for the holy grail. i.e. is still worth doing long-term, but in the real world of making and testing products one has to also make use of simple, isolated tests that focus on a small set of variables and hold other variables constant.

    A grand unified 'Fork Flex' theory that takes into account headtube flex, wheel flex during cornering vs pedal strokes, wind direction, whether the rider is wearing spandex vs baggie shorts, etc etc etc, is a fun thing to think about and work toward but I hope you were joking when you said that no conclusions can be made until a grand unified theory is developed and proven.
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    I assume they measure torsion in a plane perpendicular with the steering axis, but what about torsion in plane with it - what could be called "independent leg movement " - that would be a result of the stiffness of thru-axle combined with the robustness of the arch, no?

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    Quote Originally Posted by The_Lecht_Rocks View Post
    as i said - how does this translate in use - i AM an engineer and value the data offered but wonder how much is actually felt by the end-user.......?
    id guess they would feel pretty similar. i have a 20mm reba and a 55 and cant notice much (if any) difference other than a maxle is easier to use.

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    b-kul : my point exactly..... so many variables equate to little noticeable difference in action.

    the lateral flex is important too - it will offer "give" during sustained cornering... less lateral flex will mean less "give" which may affect fork performance................

    perhaps................

    in real terms, neither fork is likely to be noodly in action - i'm surprised the fox lost out with 34mm stanchions in torsion, but as mentioned, perhaps axle stiffness is more important.....

    so is it worth opting for the 32mm fox in preference to the 34 for general XC / trail riding

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    All this begs the question: why in the heck did fox go with the 15mm qr on this fork? they obviously see the advantage of the 20mm, since they use it on their DH forks. It adds minimal weight. So why go half way Fox??

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    Quote Originally Posted by No Agenda View Post
    I assume they measure torsion in a plane perpendicular with the steering axis, but what about torsion in plane with it - what could be called "independent leg movement " - that would be a result of the stiffness of thru-axle combined with the robustness of the arch, no?
    I think I understand what you're saying. If the "torsion" they measured is pure torque applied to the wheel (i.e. a positive force at the rim and an equal negative force at 180 degrees from the positive, twisting around the axis of the steerer), then I believe they should have measured an additional metric; one that is related to independant leg movement. Hard cornering induces a lateral load on the tire/wheel near the contact patch, the resulting moment causing the wheel to want to rotate about an axis that's 90 deg. from the axle, nearly parallel to the ground. Did they simulate such a loading at all?
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    Quote Originally Posted by bholwell View Post
    I think I understand what you're saying. If the "torsion" they measured is pure torque applied to the wheel (i.e. a positive force at the rim and an equal negative force at 180 degrees from the positive, twisting around the axis of the steerer), then I believe they should have measured an additional metric; one that is related to independant leg movement. Hard cornering induces a lateral load on the tire/wheel near the contact patch, the resulting moment causing the wheel to want to rotate about an axis that's 90 deg. from the axle, nearly parallel to the ground. Did they simulate such a loading at all?
    That. It seems that hard cornering is as common, if not more so, than riding lines that are apt to try and deflect the wheel in a left/right direction.

    Really, a ride often involves cornering while concurrently negotiating obstacles, so if they only tested torsional stiffness the easy way (fork dropouts clasped solidly and a strain gauge on the steerer) then the test is pretty limited in scope.

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    Quote Originally Posted by wasfast View Post
    All this begs the question: why in the heck did fox go with the 15mm qr on this fork? they obviously see the advantage of the 20mm, since they use it on their DH forks. It adds minimal weight. So why go half way Fox??

    great point - it does seem erroneous to spec the 15mm on the 34mm fork...........

  18. #18
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    Quote Originally Posted by No Agenda View Post
    That. It seems that hard cornering is as common, if not more so, than riding lines that are apt to try and deflect the wheel in a left/right direction.

    Really, a ride often involves cornering while concurrently negotiating obstacles, so if they only tested torsional stiffness the easy way (fork dropouts clasped solidly and a strain gauge on the steerer) then the test is pretty limited in scope.
    Yes, we're in agreement.
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    15mm is silly, just another standard marketed as being "lighter than 20mm and stronger than QR." In reality, it isn't as strong as 20mm and isn't really much lighter than a 20mm setup, especially with the Maxle Light from RS.

    Suckers bought in....and had to buy new hubs/conversion kits/wheels to keep up with their beloved new 15mm standard.

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    What this data suggests is that Fox should have designed their Float 34 around a 20mm T/A! If Rockshox is smart they'll build their next long travel 29er fork with a thicker and more rigid stanchion.

    Thicker stanchions for a 29er fork are a no brainer . If you view the fork stanchion as a giant lever arm a 29er fork will produce more leverage for any given level of travel than a comparable 26 inch fork as a result manufacturers SHOULD have made long travel 29er forks more rigid at some point: personally I think this should have happened around 140 and possibly even 120mm.

  21. #21
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    Quote Originally Posted by wasfast View Post
    All this begs the question: why in the heck did fox go with the 15mm qr on this fork? they obviously see the advantage of the 20mm, since they use it on their DH forks. It adds minimal weight. So why go half way Fox??
    shimano likes the 15mm system best and has courted most manufactures that way for trail forks.

  22. #22
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    Agreed !

    Quote Originally Posted by CharacterZero View Post
    15mm is silly


    No doubt.......however , I 'm going to give a Fox 34 Float a try anyway because I got a good deal on one ! TIG.

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    wow, I guess I thought it was obvious I was answering the question on how this effects the rider (as the final result). Guess smart people can't always pick up on the obvious
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    Quote Originally Posted by BacDoc View Post
    Let me translate the German engineering data to American mountain biker parameters:

    50% say-
    "That Fox is a totally sick fork that shreds all terrain and blows the Rock Shock away!"

    The other 50% say-
    "That Rock Shock is a totally sick fork that shreds all terrain and blows the Fox away!"

    This was double blind random controlled data published in a peer reviewed journal, so you can accept this as fact.
    exactly, now lets go ride!
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  25. #25
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    Let me translate the German engineering data to American mountain biker parameters:

    50% say-
    "That Fox is a totally sick fork that shreds all terrain and blows the Rock Shock away!"

    The other 50% say-
    "That Rock Shock is a totally sick fork that shreds all terrain and blows the Fox away!"

    This was double blind random controlled data published in a peer reviewed journal, so you can accept this as fact.

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    The reason a thicker stanchion in conjunction with a 20mm might be the optimal solution is the fork itself. As a gross oversimplication I believe the fork is experiencing rotional forces in two planes:
    1. The plane where the stanchion runs up and down the bike
    2. The plane where the wheel axle is located

    Whether you're corning or going through a rock garden both planes are going to be stressed,however from anecdotal reports that I've read the 34mm stanchion seems to be better through rough terrain. However I suspect that the 20mm t/a is going to be faster through a corner since I assume that the axle will be the fulcrim.

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    Hey TIG,

    when you say good deal, how bout providing a number and from where?? Or is this secret black ops sort of stuff?

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    Quote Originally Posted by bholwell View Post
    I think I understand what you're saying. If the "torsion" they measured is pure torque applied to the wheel (i.e. a positive force at the rim and an equal negative force at 180 degrees from the positive, twisting around the axis of the steerer), then I believe they should have measured an additional metric; one that is related to independant leg movement. Hard cornering induces a lateral load on the tire/wheel near the contact patch, the resulting moment causing the wheel to want to rotate about an axis that's 90 deg. from the axle, nearly parallel to the ground. Did they simulate such a loading at all?
    What would be pretty bad ass is a figure (both front and side elevations) showing the strain distribution in each piece.
    something like this totally made up figure I pulled out of my ass:
    Attached Thumbnails Attached Thumbnails Fox 34 vs Rock Shox stiffness, tested-bike-steering-torsion-dist-made-up-.jpg  

    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  29. #29
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    Quote Originally Posted by mefistofeles View Post
    If you view the fork stanchion as a giant lever arm a 29er fork will produce more leverage for any given level of travel than a comparable 26 inch fork
    Is this due to rotational mass only/distance from the center of the wheel?

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    Quote Originally Posted by CharacterZero View Post
    Is this due to rotational mass only/distance from the center of the wheel?
    Longer stanchion.

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    Ah, of course.

  32. #32
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    Quote Originally Posted by mefistofeles View Post
    What this data suggests is that Fox should have designed their Float 34 around a 20mm T/A! If Rockshox is smart they'll build their next long travel 29er fork with a thicker and more rigid stanchion.

    Thicker stanchions for a 29er fork are a no brainer . If you view the fork stanchion as a giant lever arm a 29er fork will produce more leverage for any given level of travel than a comparable 26 inch fork as a result manufacturers SHOULD have made long travel 29er forks more rigid at some point: personally I think this should have happened around 140 and possibly even 120mm.
    OD isn't the only stanchion dimension, and far from the only design spec that affects rigidity, as the study clearly demonstrates.
    Do you know that 29er fork stanchions are of the same tubing spec as 26" forks for mfr's who produce both?
    Do you know that the additional "need" is not addressed via any other design spec?

    To what extent does the additional momentum (both linear and angular) and reduced angle of attack of the 29er wheel offset this "no brainer"?

    I'm not sure I would jump to the conclusion that these pretty basic and focal design criteria have been ignored by suspension designers for over 10 years. Maybe, though...
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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    [QUOTE=meltingfeather;8797976
    To what extent does the additional momentum (both linear and angular) and reduced angle of attack of the 29er wheel offset this "no brainer"?

    I'm not sure I would jump to the conclusion that these pretty basic and focal design criteria have been ignored by suspension designers for over 10 years. Maybe, though... [/QUOTE]

    That is what I was thinking...well said.

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    Why don't they just make a freakin AM 29er fork with 36mm stanchions and 20mm axle already! It's inevitable that's where it's headed, so please fox/rs/marzocchi, stop dipping your toe in and just jump in for cripes sake!

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    I've owned two Reba 20mm thru axle forks (29er). An 120 and a 140 Ti. And currently own an fox 34mm.
    With that said, I trashed the rebas. I torqed the lower legs so they couldn't be used. ( leaning to one side, rubbing the left leg)

    The 34.... hands down puts up with way more abuse.

    I'm a super clyde btw

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    Quote Originally Posted by masterofnone View Post
    Why don't they just make a freakin AM 29er fork with 36mm stanchions and 20mm axle already! It's inevitable that's where it's headed, so please fox/rs/marzocchi, stop dipping your toe in and just jump in for cripes sake!
    I'd settle for 35mm as seen on the Lyric, but yeah.

    From what I've read/heard it's about numbers. Not enough sales in 29" AM, which is really one of those chicken/egg deals...

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    Most designs are smart enough to clamp the over-sized axle in order to tie each leg together, rigidly. QR15 doesn't do that, and it's a shame. 15 is fine for aggressive trail riding, but the lags need to clamp the axle in order for it to work to its potential.

    That said, I have a 34 Talas and it's really great.

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    Quote Originally Posted by No Agenda View Post
    From what I've read/heard it's about numbers. Not enough sales in 29" AM, which is really one of those chicken/egg deals...
    I can understand that justification for the Reba 140. They took a low investment approach and did the most they could. The Fox 34mm? Don't get it. If you're going to tool up a whole new line, why only go half way?

  39. #39
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    [QUOTE=D.F.L.;8798441]Most designs are smart enough to clamp the over-sized axle in order to tie each leg together, rigidly. QR15 doesn't do that, and it's a shame. 15 is fine for aggressive trail riding, but the lags need to clamp the axle in order for it to work to its potential.

    This is a very good point and definitely one of the weaknesses of Fox's QR15 design. To explain it better to those who haven't used both systems:

    * The Fox QR15 has radial slop between the 15mm axle and the fork sliders. The axle just applies a strong axial clamping force to the hub between the sliders so there is always a bit of play there.

    * The RS Maxle system not only applies the axial clamping force but also expands radially against the sliders to fill the gap. This still allows a tiny bit of movement but much less than the QR15 system.

    If you look at Fox's 20mm axle design on the 36 series forks you'll see that they clamp the axle axially and radially to eliminate pretty much all movement (except slop between the hub and axle). It is the best of both worlds and works really well.

    Along with the axle design you'd get different measurements for different forks of the same model because bushing play factors into the equation heavily. To get some meaningful #s they'd have to measure several forks from several production batches and also do the independent leg movement measurement.

    I'd like to read the German Bike mag test some time. There's obviously more to it than written above because the giving one number for Nm/deg for torsion shows that they measured at one point. I highly doubt that the torsion is linear in Nm/deg so they'd really need to plot the torque vs degree twist to get a better understanding.

    I'm also wondering how they measured the braking stiffness if the units are truly in Nm/deg. If all they did was clamp the steerer tube and push back on the axle the units should be N/deg.

    Anyways, the numbers aren't all that surprising. The 32mm Fox F29 is far more flexible under braking than the Reba 29 IMHO. Fox's crowns are far too skinny even in the tapered version. I would expect the 34 to be stiffer under braking but the crown is pretty scrawny so the 15% seems to be in the ballpark.
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    i don't know what is nerdier, the fact that you guys post in this much techno detail, or the fact that i find it fascinating. another tire thread, oh please, i need the details, the numbers, the gushing praise and rabid analysis, bring it!!

  41. #41
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    Come on, stop whining about the axle and stanchion standards and get out riding!

    My single FS bike has to cover a lot of different use. I like 15QR because it offers the opportunity to use both my light race wheels (9/15mm hubs) and my 15mm AM-wheels. If I had a bike for each purpose I would probably go for 20mm on the AM rig, but 20mm and XC-racing just don't match in my world, and that matters to a lot of people. If you are a clyde and/or ride really aggressively, go with the 20mm axle. Be my guest! But if you are 170 lbs and ride techy singletrack - who really feels the difference? On the other hand, I never really felt my QRs flexing too much either....

    Horses for courses. Now, if the Fox 34 is not stiff enough due to the "less than 36mm tubes" or the steering suffers from the "not up to standard" 15QR I probably will not feel neither....

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    They don't explain the testing methodology very well in the mag. Check the website, it might have more detail.
    Home*|*BIKE-MAGAZIN.DE webcode 3751

    They do describe the braking stiffness test a bit:
    excuse the poor grammar, I'm no translator and my German is only so-so:
    The fork is loaded against the travel direction with a weight that is attached to the brake mounts with an adapter. This explains the torque value vs plain force value.

  43. #43
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    Quote Originally Posted by bog View Post
    I'd like to read the German Bike mag test some time. There's obviously more to it than written above because the giving one number for Nm/deg for torsion shows that they measured at one point. I highly doubt that the torsion is linear in Nm/deg so they'd really need to plot the torque vs degree twist to get a better understanding.
    Interesting point.
    Quote Originally Posted by bog View Post
    I'm also wondering how they measured the braking stiffness if the units are truly in Nm/deg. If all they did was clamp the steerer tube and push back on the axle the units should be N/deg.
    The distance from the applied load (axle) to where the fork is clamped/supported (steer tube) is the m.
    Last edited by meltingfeather; 12-06-2011 at 08:26 AM.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  44. #44
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    [QUOTE=meltingfeather;8800100][QUOTE=bog;8799448]
    Interesting point.
    [QUOTE=bog;8799448]
    The distance from the applied load (axle) to where the fork is clamped/supported (steer tube) is the m.[/QUOTE

    That still doesn,t make it a torque which is where NM comes from. If the pushed straight back on the axle it should have been a N/mm measurement so I don't think this is what they did. You aren't rotating around an axis so trying to turn a force into a torque doesn't make sense in this case.

    The magazine code doesn't work for me but it makes some sense that they loaded up the disc tab and gave it a twist somehow.
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    Quote Originally Posted by bog View Post
    That still doesn,t make it a torque which is where NM comes from. If the pushed straight back on the axle it should have been a N/mm measurement so I don't think this is what they did. You aren't rotating around an axis so trying to turn a force into a torque doesn't make sense in this case.

    The magazine code doesn't work for me but it makes some sense that they loaded up the disc tab and gave it a twist somehow.
    Distance from applied load to support with the load vector not pointing through the support point necessarily means torque... by definition. The same force applied to a shorter fork (e.g., a 26" fork) would produce a lower moment.
    In very basic terms, what would happen if the clamp were free to rotate in the plane of the bike? It would... and the fork doesn't change in length, so you have an arc, which is where degrees of strain/distortion comes from.
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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    Quote Originally Posted by Endomaniac View Post
    Interesting to read, I donít think this says much about 32/34mm or 15/20mm though. ... Crown design has alot to do with these characteristics...
    Quote Originally Posted by meltingfeather
    I'm not sure I would jump to the conclusion that these pretty basic and focal design criteria have been ignored by suspension designers for over 10 years. Maybe, though...
    Yes.

    Quote Originally Posted by wasfast
    All this begs the question: why in the heck did fox go with the 15mm qr on this fork?
    Quote Originally Posted by The_Lecht_Rocks
    ...it does seem erroneous to spec the 15mm on the 34mm fork...
    Quote Originally Posted by CharacterZero
    15mm is silly, just another standard marketed as being "lighter than 20mm and stronger than QR."...
    Quote Originally Posted by mefistofeles
    What this data suggests is that Fox should have designed their Float 34 around a 20mm T/A!
    Quote Originally Posted by D.F.L.
    Most designs are smart enough to clamp the over-sized axle in order to tie each leg together, rigidly. QR15 doesn't do that, and it's a shame.
    And you all fell for it.

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    Quote Originally Posted by craigsj View Post
    And you all fell for it.

    Never miss an opportunity to harp on your favorite prejudices.
    fell for what ? the 20mm is inherently stronger and likely more stiff [flange facing on 20mm hub is increased over comparitive 15mm hub for instance. viz a viz......

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    Quote Originally Posted by The_Lecht_Rocks View Post
    fell for what ? the 20mm is inherently stronger and likely more stiff [flange facing on 20mm hub is increased over comparitive 15mm hub for instance. viz a viz......
    Yes, exactly. It was a fork test, not an axle test. You read into it exactly what you wanted to. By all means, though, pound on it some more.

  49. #49
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    Quote Originally Posted by meltingfeather View Post
    Distance from applied load to support with the load vector not pointing through the support point necessarily means torque... by definition. The same force applied to a shorter fork (e.g., a 26" fork) would produce a lower moment.
    In very basic terms, what would happen if the clamp were free to rotate in the plane of the bike? It would... and the fork doesn't change in length, so you have an arc, which is where degrees of strain/distortion comes from.
    Sorry, you're grasping at straws here and don't seem to get that it is pretty much a beam bending model. We're talking about clamping the steerer tube rigidly then applying a force directly down on the axle to get the fork to deflect backwards. There is no torque applied nor is there a measurement of torque anywhere in this test (although it doesn't seem like this was actually the test method). Yes, you can create a calculation with F x d but it tells you absolutely nothing and you are not applying torque to the fork.

    In reality you would graph the applied Force on the Y-axis and the axle displacement on the X-axis to get the deflection curve. This test has absolutely nothing to do with torque, moments, or degrees of rotation which tells me that this is not the test that was performed to get the NM/deg measurement.
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    Quote Originally Posted by bog View Post
    In reality you would graph the applied Force on the Y-axis and the axle displacement on the X-axis to get the deflection curve. This test has absolutely nothing to do with torque, moments, or degrees of rotation which tells me that this is not the test that was performed to get the NM/deg measurement.
    I completely agree. I haven't read the article, but from what I know the reporting method doesn't seem sound, and therefore it casts doubt on the test procedure. And I know of many who are also skeptical of this magazine's test procedures, so this doesn't suprise me...

    (BTW, don't argue with Feather- it's an exercise in futility! )
    Tire Design & Development Engineer. The opinions expressed in this forum are solely my own.

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