At what point is a stem too short to where it affects handling?
 

A friend of mine bought a decent road bike from CL based on height alone, he's 5'7" and bought a 52cm frame with a 90mm stem and the reach is just slightly too long for him (He has freakishly short arms). He's been dealing with some numbness in fingers after rides and doesn't have a slight bend in the elbow like he should unless he puts his hands an inch or so behind the rubber hoods. Ideally everything else about the frame is perfect for him though (a 50cm frame would be too small for him).


With the bike being a small sized frame (52cm), how bad (if at all), would it be for him to drop down to either an 80mm or possibly 75mm stem? I won't advise him to go any lower than 75mm because I've read that there's a point where going too short can affect handling and twitchiness.

I agree he should probably try a shorter stem, but it's impossible to say how much shorter. 52 could be a frame size or two small for him based on leg length, but we don't know. But, I finally learned the truth that a centimeter is a mile when adjusting stem length. I wouldn't make a jump larger than 1 cm at a time.

I have made a lot of stem changes on my bikes, and really have not seen any significant changes in handling, until the stem gets 3 cm too long, like a 130 mm or so. I've also gone as small as 6 cm extension on one bike, and handling was not an issue. What has been of concern are changes in fit - scrunched back, too much reach, too tiring to stay on the hoods, and other issues.

But basically, my opinion is, get the comfort and fit right. The effect on handling is a lot smaller than those effects.

The solution is to install a stem riser to get the bars up to a more comfortable riding position. Your hands, arms and back will feel more relaxed. From there you can make stem adjustments to dial in the fit.

Maybe he could try a short reach handlebar.

He's already has a reasonable amount of spacers under the stem, so I guess the shorter stem is the wya to go from here.

I agree with Road Fan, especially the last line. My '91 Bianchi came to me with a 40mm (yes!) stem, and I was able to ride it for a couple of years just fine before adopting more of a stretched-out position. I now use an 80mm stem on that bike, and have just moved up to a 90mm stem on my '87 Bianchi, after using an 80mm on that one for a couple of years.

While stem length does have a slight impact on the arc of the steering range, I wouldn't be surprised if it's actually the amount of weight over the front wheel that gives people the impression that longer stems lend more stability.

This is absolutely it, in my opinion. When I indulged myself with a custom bike, the only difference in fit between that and the Giant TCR I'd been riding was that my centre of gravity was moved slightly forward, with a 120mm stem instead of 100 mm. The new bike handles better as a result, but I think it's the weight distribution, little or nothing to do with the steering arc.

Thanks! I get another "platitude" out of this: Let your fit evolve as you gain fitness and flexibility.

Maybe that nice 130 mm Cinelli stem will end up being right for my little 52 cm Masi, after I finish growing up!

Yep! I've been riding road bikes for 6 years now, and I still tweak my fit now and then. I wonder if it'll ever stop evolving. :)

I’m 5’7” and ride a 52CM Cannondale CAAD10 5. Several months ago I swapped out the OE Cannondale C3, 90mm x 31.8mm, 6 deg stem with a SPECIALIZED 75mm x 31.8mm, 24 deg stem. Handling hasn’t noticeably changed, and it is much more comfortable to ride, especially over longer distances.

Before
http://ptdoityourself.net/bike/image.../CAAD10_07.jpg


After

http://www.ptdoityourself.net/bike/bikewt_03.jpg

Stem length doesn't affect stability the way people think; as long as a bike has reasonable trail - which is set for by fork rake - it will steer perfectly well with any length of stem. Mtbs and bmx often run very short stems indeed without having problems - the stems can hold the bars flat against the steerer.

Absolutely correct. If you look at the actual amount of handlebar movement required to steer a moving road bike (even in crit racing), you'll quickly realize that steering arc makes virtually no difference. Weight distribution, on the other hand, is very important. It has a significant effect on how the bike "turns in" as well as how much traction you have through the corner.

that's actually not true at all, considering he has short arms and shortening the stem will only get you so far. when you have an issue like this, you have 2 choices, larger frame/shorter stem or shorter frame/longer stem. just because people 5'7" tall usually ride 52cm frames doesn't mean that a 52cm frame is right for him...

that fine, and if he still struggling a bit than he could always use a shorter reach handlebar too...