Comments on: Tuning The Ride: 29″ers and Steering Performance http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/ 29er Bike Reviews, Rumors and News Fri, 04 Jul 2008 16:02:19 +0000 http://wordpress.org/?v=2.5.1 By: Dr.Dover http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-33574 Dr.Dover Fri, 25 Jan 2008 17:10:48 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-33574 I've been reading up on all the head tube angles, trailing, corrected suspension etc., etc.... I've come to the conclusion that one must build it and ride it to really see what happens. I'm getting ready to 69er my Trance. Putting a Reba 29 on the front end. The head tube angle is going to be very slack. I'm kind of concerned, but it is the only way to find out. I've got a Mary SS that is a real 29er. Love that lay out in full rigid. We'll see what happens with the Trance. I've tried calculating this and that and I get to a point where my brain explodes. Intersting posts and commentary on the 29er steering. Thanks a bunch! I enjoy the thought it generates for me. I’ve been reading up on all the head tube angles, trailing, corrected suspension etc., etc…. I’ve come to the conclusion that one must build it and ride it to really see what happens. I’m getting ready to 69er my Trance. Putting a Reba 29 on the front end. The head tube angle is going to be very slack. I’m kind of concerned, but it is the only way to find out. I’ve got a Mary SS that is a real 29er. Love that lay out in full rigid. We’ll see what happens with the Trance. I’ve tried calculating this and that and I get to a point where my brain explodes. Intersting posts and commentary on the 29er steering. Thanks a bunch! I enjoy the thought it generates for me.

]]> By: jay t http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-33376 jay t Wed, 23 Jan 2008 00:54:53 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-33376 i ride 3 different bikes, a curtlo fully rigid 24hr, a haro 29 ss, and a 05 sworks stumpjumper. first go to bike is almost always the stumpy. full susp, comfort, handling.... easy on the back (43yr old) second is the haro and lastly the curtlo. i have played with the travle on the stumpy (talas fork), swapped the 26 fr. wheel for the 29 on the curtlo to make a 69r. i,like the relaxed angles i guess because when i put the 29 fr. wheel on the curtlo it made it much more comfortable, and better handling. fork on the curtlo is a vicious cycles 100mm corrected, so plenty long enough for the 29 wheel. came to the conclusion that it is closer to the stumpy in layout with a larger fr. tire. ie., its what i'm used to. if you have the chance, swap some parts around, you may be suprised that you like not what you thought you would. now, next i wanna try a 29r full susp. that has a little laid back geometry, sound like the ticket for me...... maybe not you. i ride 3 different bikes, a curtlo fully rigid 24hr, a haro 29 ss, and a 05 sworks stumpjumper. first go to bike is almost always the stumpy. full susp, comfort, handling…. easy on the back (43yr old)
second is the haro and lastly the curtlo. i have played with the travle on the stumpy (talas fork), swapped the 26 fr. wheel for the 29 on the curtlo to make a 69r.
i,like the relaxed angles i guess because when i put the 29 fr. wheel on the curtlo it made it much more comfortable, and better handling. fork on the curtlo is a vicious cycles 100mm corrected, so plenty long enough for the 29 wheel. came to the conclusion that it is closer to the stumpy in layout with a larger fr. tire. ie., its what i’m used to. if you have the chance, swap some parts around, you may be suprised that you like not what you thought you would. now, next i wanna try a 29r full susp. that has a little laid back geometry, sound like the ticket for me…… maybe not you.

]]> By: Kosmo http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32101 Kosmo Mon, 07 Jan 2008 02:24:26 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32101 This is highly subjective, but while I loved my 26er 5-Spot, it had a kind of slash and burn feel to cornering. Not bad at all, but that was the feel. Switching to a 29er Sultan, I didn't find the handling any slower or faster, but definitely a smoother "carving" kind of feel to cornering. I love it. I treated myself to a new Superfly race bike, and with only a few winter rides so far, it kind of hits the middle ground between the two (I know, HT to rear sus comparo, but it's all I've got). I like it, and suspect I'd absolutely love it WITHOUT the different offset F29 fork. A long-winded way towards saying that I hope the whole 29er cornering experience isn't screwed up by trying to chase the same feel of a 26er! This is highly subjective, but while I loved my 26er 5-Spot, it had a kind of slash and burn feel to cornering. Not bad at all, but that was the feel. Switching to a 29er Sultan, I didn’t find the handling any slower or faster, but definitely a smoother “carving” kind of feel to cornering. I love it. I treated myself to a new Superfly race bike, and with only a few winter rides so far, it kind of hits the middle ground between the two (I know, HT to rear sus comparo, but it’s all I’ve got). I like it, and suspect I’d absolutely love it WITHOUT the different offset F29 fork.

A long-winded way towards saying that I hope the whole 29er cornering experience isn’t screwed up by trying to chase the same feel of a 26er!

]]> By: jeremy Uk http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32088 jeremy Uk Sun, 06 Jan 2008 22:55:16 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32088 You're correct Mike. I redid my geometry with a little more care. Apologies. Well at least my head's a little clearer. Anyway tomorrow my 16" On-One should arrive [71/47] and I can go out and compare it with what I remember of my old Fisher [clue christened 'the Lorry', er that's english for truck] That is if the projectile vomiting bug has finally done with me. You’re correct Mike. I redid my geometry with a little more care. Apologies.
Well at least my head’s a little clearer. Anyway tomorrow my 16″ On-One should arrive [71/47] and I can go out and compare it with what I remember of my old Fisher [clue christened 'the Lorry', er that's english for truck]
That is if the projectile vomiting bug has finally done with me.

]]> By: Jared http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32086 Jared Sun, 06 Jan 2008 22:45:03 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32086 Hehe. No worries. I always assume everyone rides sprung, not rigid. :) Hehe. No worries. I always assume everyone rides sprung, not rigid. :)

]]> By: Mike http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32085 Mike Sun, 06 Jan 2008 22:23:25 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32085 Sorry for that confusion. I've been spending all my time lately working with (and riding) rigid forks that I sometimes forget folks are talking suspension forks. :-) Sorry for that confusion. I’ve been spending all my time lately working with (and riding) rigid forks that I sometimes forget folks are talking suspension forks. :-)

]]> By: Jared http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32084 Jared Sun, 06 Jan 2008 22:10:32 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32084 Mike: That was the point of that first part of my last post. Trail IS changed IF A-C changes <i>because</i> the altered A-C length changes HA. The originally spec'd HA on a frame is ONLY applicable if the A-C the frame was designed around remains intact post fork change (as you eventually alluded to). A-C is pertinent in determining HA, therefore has effect on trail (though it is not calculated for in trail formulas because the math has already been done in determining HA). I think the horse is beginning to stink. :) Anyway, I for one look forward to GT's next post as I have changed the handling of my bike dramatically for the better with a fork swap. Mike: That was the point of that first part of my last post. Trail IS changed IF A-C changes because the altered A-C length changes HA. The originally spec’d HA on a frame is ONLY applicable if the A-C the frame was designed around remains intact post fork change (as you eventually alluded to). A-C is pertinent in determining HA, therefore has effect on trail (though it is not calculated for in trail formulas because the math has already been done in determining HA). I think the horse is beginning to stink. :)

Anyway, I for one look forward to GT’s next post as I have changed the handling of my bike dramatically for the better with a fork swap.

]]> By: Mike http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32081 Mike Sun, 06 Jan 2008 21:39:12 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32081 Trail is not a function of fork length (at least the A-C). It's a function of wheel diameter, fork offset, and head angle. This applies only to rigid forks. Does anyone actually use suspension forks ;-) ? The only reason the "relative" trail changes on a suspension fork as it "shortens" is because the compression of the fork changes the head angle Those numbers are really reference. Upon further thought, if you took a bike with a suspension fork, fixed the head tube so it's angle did not change and compressed the fork up from below, the trail would not change. Luckily, the bike industry is chock full of very talented designers who have, for the most part, dialed in geometry very nicely. My head hurts now :-) Trail is not a function of fork length (at least the A-C). It’s a function of wheel diameter, fork offset, and head angle. This applies only to rigid forks. Does anyone actually use suspension forks ;-) ? The only reason the “relative” trail changes on a suspension fork as it “shortens” is because the compression of the fork changes the head angle

Those numbers are really reference.

Upon further thought, if you took a bike with a suspension fork, fixed the head tube so it’s angle did not change and compressed the fork up from below, the trail would not change.

Luckily, the bike industry is chock full of very talented designers who have, for the most part, dialed in geometry very nicely.

My head hurts now :-)

]]> By: jeremy Uk http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32069 jeremy Uk Sun, 06 Jan 2008 19:50:52 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32069 I don't pretend to understand the trail calculator, just proferred it as evidence that fork length is a variable. I don’t pretend to understand the trail calculator, just proferred it as evidence that fork length is a variable.

]]> By: Guitar Ted http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32068 Guitar Ted Sun, 06 Jan 2008 19:42:01 +0000 http://twentynineinches.com/2008/01/05/tuning-the-ride-29ers-and-steering-performance/#comment-32068 Well, I expected the numbers to get flaunted and the trail calculators to be proffered, but remember, those are only guide posts and not a hard and fast way to identify how a bike will handle for you and your riding style. I like this part of Jared's comment, which I think sums up the issue succintly: "I think this issue has been beat to death though. Most often, these numbers are just that; numbers. I thought I could predict the ride of my bike when I changed the fork, but alas, I was wrong. As so many others have said before, you’ve just GOT to ride it before you really know." This has been my experience as well. The "human factor" overides all of these numbers and theories. It is vastly more complex, unpredictable, and adapative. It cannot be neatly packaged in a trail calculator from an online source. I'm not saying that those numbers are worthless, or that we should ignore them, but that they are only a hint, ( a good hint perhaps) at what you might expect from any certain sort of geometry for you and your trails. Again as Jared says, "...you've just GOT to ride it before you really know." It is pretty much exactly what I was trying to say in the post. There is no "easy button" to push when it comes to the handling characteristics of 29"ers these days. Heck, back in the early 90's print magazines made a living out of dissecting the handling traits of trail bikes that had EXACTLY the same geometry, and yet they were able to winnow out the differences between the different models. Interesting if you consider it. ;) Well, I expected the numbers to get flaunted and the trail calculators to be proffered, but remember, those are only guide posts and not a hard and fast way to identify how a bike will handle for you and your riding style. I like this part of Jared’s comment, which I think sums up the issue succintly:

“I think this issue has been beat to death though. Most often, these numbers are just that; numbers. I thought I could predict the ride of my bike when I changed the fork, but alas, I was wrong. As so many others have said before, you’ve just GOT to ride it before you really know.”

This has been my experience as well. The “human factor” overides all of these numbers and theories. It is vastly more complex, unpredictable, and adapative. It cannot be neatly packaged in a trail calculator from an online source.

I’m not saying that those numbers are worthless, or that we should ignore them, but that they are only a hint, ( a good hint perhaps) at what you might expect from any certain sort of geometry for you and your trails. Again as Jared says, “…you’ve just GOT to ride it before you really know.” It is pretty much exactly what I was trying to say in the post. There is no “easy button” to push when it comes to the handling characteristics of 29″ers these days.

Heck, back in the early 90’s print magazines made a living out of dissecting the handling traits of trail bikes that had EXACTLY the same geometry, and yet they were able to winnow out the differences between the different models. Interesting if you consider it. ;)

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