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Advice on stem length experiments

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Advice on stem length experiments

Old 05-16-22, 04:14 PM
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nPn
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Advice on stem length experiments

I recently acquired a size 54 2010 Roubaix Comp. This is not my first road bike, I have been riding regularly for many years. My other bikes are a size 56 2012 Revenio and a size 56 2020 Broam. I recently had this "new" bike fitted and I think it feels pretty good position wise, but I think it feels a little twitchy. By twitchy I mean I fell a little less confident taking a hand off the bar to say, indicate I am about to make a turn. Also I don't feel as confident with higher speed descents. It could all just be in my head since I know the stem was sized a little shorter then the stock stem would have been (75mm vs 100mm). I am hoping this is just in my head and I will get used to but if not I may try using a longer stem to see if that helps.


The specs say head tube angle is 72 and the effective stem angle is 13 def (+17 stem - 4 flange). This stem comparison tool seems to indicate that keeping the same spacers and flange and just swapping out the 17 deg x 75mm stem with a 17 deg 100mm stem would raise the bar 13mm and push it out 21mm. I realize it's impossible not to change my position, and so if it changes I think I would rather change slightly toward a more relaxed position vs a more aggressive position. So a few questions. How long should I give myself to get used to the current setup to see if the feeling of twitchyness goes away? Does this seem like it would be too big of an initial change to try? Which direction would this change be in, relaxed or aggressive? Any other suggestions?
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Old 05-16-22, 04:59 PM
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Might just need to ride it some more and get use to it.

After I got my 56cm Tarmac I thought the bars were too far out front, so I got a 70 mm stem to replace the 100 mm stem. First few rides were maybe what you call twitchy. Especially when doing downhill twisty paved trails and roads at speed or when encountering gusts. But a dozen or two rides and all that was in the past.

However, a few months later I also got narrower bars, went from 42 cm to 38 cm. And I swear the feeling of those same twisty turns and everything else became better than ever. Whether there is some math behind that I don't know.

Neither stem nor bars will do anything for riding no handed. But if your bars are 42 cm or wider, then narrower might make taking one hand off the bar easier for you. Narrower bars will also make your bike more responsive when you need to avoid sudden hazards in the road.
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Old 05-16-22, 08:57 PM
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If you had the bike fitted, one would assume that the fitter addressed upper body positioning, including hip angle and torso/upper arm angle. IF those things were addressed and changes made to get the angles right, then don't mess with the fit until you have a couple thousand miles on the bike. Different bikes handle differently. A lot of that is that different geometries deliver different responses to rider inputs. The bike should be able to teach you what rider inputs it likes and what it doesn't like. IOW, you'll get used to it. I sure wouldn't make huge changes in my fit like that - and those are huge changes - without going in for a refit, that is unless I thought myself a better fitter than the pro at the shop.
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Old 05-17-22, 08:45 PM
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IIRC, fork rake and trail alos affect steering quickness. Gotta ride it more and get used to it.
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Old 05-18-22, 09:07 AM
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Originally Posted by nPn View Post
I I am hoping this is just in my head and I will get used to but if not I may try using a longer stem to see if that helps.
It’s not just in your head (the physics are that stem length matters on this) but you almost certainly will get used to it. If it were me, I would just ride the bike as is until then, rather than making big changes to fit for non-fit reasons.

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Old 05-19-22, 08:41 PM
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If you aren’t confident taking one hand off the bar to signal a turn, I have to wonder if a different stem would make any difference; it sounds like other geometry is contributing to the perceived twitchiness. I don’t know how many miles it will take to acclimate, but definitely more than you’ve put on it so far. My advice would be to go out and “play” — stuff it into some corners, put your weight way forward and way back, sit on the top tube, ride no-hands, bunny-hop the train tracks. Bend the thing to your will until you feel at home on it.
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Old 05-20-22, 09:22 AM
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Originally Posted by nPn View Post
I recently acquired a size 54 2010 Roubaix Comp. This is not my first road bike, I have been riding regularly for many years. My other bikes are a size 56 2012 Revenio and a size 56 2020 Broam. I recently had this "new" bike fitted and I think it feels pretty good position wise, but I think it feels a little twitchy. By twitchy I mean I fell a little less confident taking a hand off the bar to say, indicate I am about to make a turn. Also I don't feel as confident with higher speed descents. It could all just be in my head since I know the stem was sized a little shorter then the stock stem would have been (75mm vs 100mm). I am hoping this is just in my head and I will get used to but if not I may try using a longer stem to see if that helps.


The specs say head tube angle is 72 and the effective stem angle is 13 def (+17 stem - 4 flange). This stem comparison tool seems to indicate that keeping the same spacers and flange and just swapping out the 17 deg x 75mm stem with a 17 deg 100mm stem would raise the bar 13mm and push it out 21mm. I realize it's impossible not to change my position, and so if it changes I think I would rather change slightly toward a more relaxed position vs a more aggressive position. So a few questions. How long should I give myself to get used to the current setup to see if the feeling of twitchyness goes away? Does this seem like it would be too big of an initial change to try? Which direction would this change be in, relaxed or aggressive? Any other suggestions?
You got a smaller frame than the other 2... which would have quite diifferent specs ??? Yes
Here are the frame spec comparisons of that era 54cm Roubaix vs 56 Revenio
https://geometrygeeks.bike/compare/r...x-pro-2010-54/
The Roubaix has a 17mm shorter TT and a 25mm shorter HT - which is expressed in the effective Reach and Stack. So, Yes, the Roubaix will feel more twitichy, in spite of the slacker Head Angle.
The "trail', although not published, is prolly the same... We have to assume the Bars (which also has effect) are 'compact' - so similar bar 'reach' along with width.
Getting a 'relaxed Fit' for a 'Comfort Ride' is never best done by going with a smaller frame...
You will likely 'adjust' to twitchy at some point, with the short stem. But you could go 20mm longer stem and get close to a similar reach. Getting a similar 'stack' is another can O worms.
All this needs consideration with the really important element of saddle position - which is really the last place to screw with position (once a good position is decided).
Stems can be had for 'cheap'. I'd get that longer stem and give it a try - worth the 'education'. Or even get a 11 or 12cm Adjustable stem (once you angle up they get really shorter...) and play around - more education...
Another tip... when you want to take one hand of the bars - signal, take a good swig of the Bidon, turn-around to look behind, etc - move the hand, which remains on the bar, onto the bartop as close to the stem as possible. MOST stable steering position, and allows the bike to track best in the direction you're pointed, without veering off line. DO make sure you have no road hazards coming... (do we need to point that out?).
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Last edited by cyclezen; 05-20-22 at 09:25 AM.
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Old 05-21-22, 02:12 PM
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Thanks for all the advice. I will definitely give myself more time/miles to adjust. I try to ride about 200 miles a week, so it should not take too long. My main reason for even thinking about this is that as @cyclezen mentioned, stems are cheap and since I feel my saddle position is really good at some point I can mark what I have now and do some experiments, but I agree I should not just start messing with my setup right after getting fitted, I need to give myself time to adapt. Thanks again all!
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Old 05-24-22, 07:08 AM
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Originally Posted by nPn View Post
I am hoping this is just in my head and I will get used to but if not I may try using a longer stem to see if that helps.
Yup, it's mostly in your head. You'll get used to it.

I used to have 100mm stem and changed to 32mm stem with short reach drop bar to experiment. A 32mm stem would actually be too short for my measurements. Steering felt twitchy at first but after nearly a month of riding with it, it doesn't feel twitchy anymore! Totally confident descending at 40 mph.
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Old 07-23-22, 11:20 AM
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Just wanted to follow up on this thread I started. As of yesterday I have ridden over 2K miles since having the bike fitted any concerns I had about the bike feeling twitchy are gone. Now I have to consider perhaps a fitting for my gravel bike. I was never really fitted for it and while I have it adjusted close to the Roubaix, it definitely has a longer reach.
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Old 08-18-22, 04:35 PM
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The trend with gravel bikes seems to be longer (frame) reach and shorter stem, with wider, often splayed out drops.

Probably the best way to compare, assuming you have saddle height and setback correct on both bikes, and the saddles are of the same length (often 11"), is to measure the distance between the nose of the saddle and the inflection point on the hoods, and also the nose of the saddle and your most comfortable position on the drops, for each bike.
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Old 08-19-22, 11:04 AM
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Since I made my first reply in this thread about going to a shorter stem, I just a few days ago put the 100 mm stem back on. Other than some minor things that might just be adjustment of where the STI's sit since I extended the reach, I haven't seen that it really makes a big difference one way or the other.

Certainly none of the big scary claims you see about shortening the stem elsewhere ever came to being. It was mainly a matter of just getting use to it like any other thing you might change up on the bike.

So if this thread is still about experimentation, the by all means I encourage one to experiment. And don't let the results of only one short ride after changing the stem keep you from doing additional rides just to see if it's more you needing some retraining than the actual change.
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Old 08-19-22, 08:06 PM
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Originally Posted by Polaris OBark View Post
The trend with gravel bikes seems to be longer (frame) reach and shorter stem, with wider, often splayed out drops.
Longer wheelbase to improve stability and reduce toe strike with fenders present. Gravel bike users are more likely to put on fenders. Improved stability over uneven terrain is an advantage for both safety and speed.

Shorter stem reduces steering effort which is nice for dealing with off-road conditions.....Consequently, a shorter stem may allow narrower drop bar or road bars to be used on a gravel bike to improve aerodynamics. I've personally tried really short stems for a gravel bike, only 35mm long, same kind you see on DH MTB's. It felt a bit twitchy at first but I fully got used to it in just one month. Once you get used to it, it's terrific. The irony is that it feels more stable than a long stem at high speed descents on both smooth and bad, uneven roads. The front wheel doesn't wobble if I change hand position while descending. I've experienced mild wobble before on a much longer stem (110mm). But not on the 35mm stem.

The shorter stem is also more stable when swerving around obstacles at lower speed. I think the "stability" brought by long stems is "faux stability". Only gives you false sense of stability because it's harder to turn the handlebar but actually makes your bike unstable and prone to coupled oscillations with body weight that can lead to speed wobble. It also increase steering effort at low speed. The only problem at the moment is that most road geometry bikes with relatively short wheelbase, short frame is designed to take ~100 mm stems.

But you can risk it and try shorter stems. It should be fine as long as your knees don't hit the handlebar while standing to pedal or getting off the saddle over bumps. And if you try shorter stem, DON'T move your saddle backward to compensate for reach as riding comfort would deteriorate if you do.
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Old 08-19-22, 10:15 PM
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Originally Posted by koala logs View Post
Longer wheelbase to improve stability and reduce toe strike with fenders present. Gravel bike users are more likely to put on fenders. Improved stability over uneven terrain is an advantage for both safety and speed.

Shorter stem reduces steering effort which is nice for dealing with off-road conditions.....Consequently, a shorter stem may allow narrower drop bar or road bars to be used on a gravel bike to improve aerodynamics. I've personally tried really short stems for a gravel bike, only 35mm long, same kind you see on DH MTB's. It felt a bit twitchy at first but I fully got used to it in just one month. Once you get used to it, it's terrific. The irony is that it feels more stable than a long stem at high speed descents on both smooth and bad, uneven roads. The front wheel doesn't wobble if I change hand position while descending. I've experienced mild wobble before on a much longer stem (110mm). But not on the 35mm stem.

The shorter stem is also more stable when swerving around obstacles at lower speed. I think the "stability" brought by long stems is "faux stability". Only gives you false sense of stability because it's harder to turn the handlebar but actually makes your bike unstable and prone to coupled oscillations with body weight that can lead to speed wobble. It also increase steering effort at low speed. The only problem at the moment is that most road geometry bikes with relatively short wheelbase, short frame is designed to take ~100 mm stems.

But you can risk it and try shorter stems. It should be fine as long as your knees don't hit the handlebar while standing to pedal or getting off the saddle over bumps. And if you try shorter stem, DON'T move your saddle backward to compensate for reach as riding comfort would deteriorate if you do.
Why are you making any assumptions about my bike, or my preferences?

I simply stated the fact that there is a trend with gravel bikes to have shorter stems and wider bars. I made no mention of my bike or its handling, but thanks for the lecture.
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Old 08-20-22, 11:29 AM
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Originally Posted by Polaris OBark View Post
Why are you making any assumptions about my bike, or my preferences?

I simply stated the fact that there is a trend with gravel bikes to have shorter stems and wider bars. I made no mention of my bike or its handling, but thanks for the lecture.
Sorry, the advice wasn't specifically for you even though I quoted your post.

I'm am simply sharing information on my own experience to explain the trend and the information is meant for everyone!
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Old 08-20-22, 11:33 AM
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Originally Posted by koala logs View Post
Sorry, ..to explain the trend and the information is meant for everyone!
Got it.

Thanks for the explanation.
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Old 10-04-22, 03:16 PM
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Stem length

What are the considerations for stem length, does it increase along with frame size like crank arm length does?

I'm 6'1 and ride an '86 58cm Centurion Ironman (aka Loretta) and 58cm '07 Scott CR1 (aka Bonnie), and I'm rebuilding/restoring an '82 60cm Puch Luzern, which I have either an 80 or 100mm stem for. I've never had a bike professionally fitted for me, I do experience some hand numbness or wrist discomfort on longer rides. I believe the numbness is worse on Bonnie, even though she has the Ritchey Comp handlebars with an anatomic ‘pistol-grip’ bend, which is more comfortable compared to Loretta's Nitto Olympiade 115 handlebars where I experience more wrist discomfort than numbness.

Obviously the recommendation is to get professionally fitted. But are there any other suggestions of the most common fitting/adjustment fixes to address these problems.
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Old 10-04-22, 03:28 PM
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They tend to increase the length with larger frames.

It is best to get the saddle height and for/aft position correct first, and then choose a stem length that lets you keep your forearm angle with the axis of your spine somewhere close to 90°. Dropping the bar height, counter-intuitively, can decrease the weight your wrists.
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Old 10-04-22, 03:55 PM
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Thank you, that's incredibly helpful, both for bike fitting and getting me to my first 10 posts.
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