Inpd

Hi,

So I've seen some riders with 150+mm stems which look a bit odd. There explanation given was that the bike was too small but the next size was too big and a long stem solves the problem.

It kind of makes sense as the main differences b/w say a size 50 and 54 is 4cm in seat tube height (which can be overcome by setting the seat higher by 4cm) and the longer stem overcomes the increase in top tube length.

a) Have people seen this before.
b) What are the downsides of a too long stem.

rms13

The downside is compromised handling. The general accepted theory is stems should be 90-120mm. I've seen some fitters say 80-140mm is acceptable range.

StanSeven

I've heard that too but I haven't seen proof. In fact the posts and comments from many people with 130-140 stems said handling is no different than 100-110 stems on the same bike.

10 Wheels

I put 140mm stems on five bikes..

Made for a much better fit.

Never noticed any problems.

redlude97

well shouldn't the comparison be made between two different size frames with the corresponding stems?

Lazyass

Long vs. Short Stem Bicycle | LIVESTRONG.COM

Macster

DON'T feed the troll.

Kimmo

I once read the optimum stem length for someone in the middle of the body proportion bell curve on the right size bike is 120mm, which has seemed pretty legit ever since. 120s suit me unless I'm on the wrong bike.

My beater is an inch or two too small and has a 130mm stem, and the handling isn't quite kosher. But the main thing wrong with it is I have toe overlap, which noone should have to deal with (small bikes should have 650c front wheels, IMO).

What makes you sure this is trolling? Is this subject like chain lube in the Mechanics forum?

Macster

I know nothing about the mechanics forum. But visit this guys profile page - he's started like 25 threads in the last 30 days. I mean, come on now, how much attention does one need? Lol

Inpd

Thanks for the comments on stem length limits.

Lets say FRAME A is 50cm and has a TT length of 54cm.
Lets say FRAME B is 54cm and has a TT length of 58cm.

Would FRAME A with 14cm seat height and a 140mm stem ride almost the same as FRAME B with 10cm seat height and a 100mm stem?

Soody

One from the archives. Note the AAA battery lights.

This is a 130mm stem on a 56 frame. I'm 6'2. The fit is a bit off in this picture and the track bars are sort of silly, but it worked. The handling wasn't bad or anything.

Toe overlap happens, but it doesn't bother me at all. My old shoes wore a hole in the front from rubbing the tire for 4 years, but the sole snapped before the hole got too big.

The only real issue is getting your stem high enough.

Kimmo

Yes, until you turn the bike. You're supposed to have a certain weight distribution relative to the head tube and wheelbase; up to a point it's better to have your weight further back from the head tube, without compromising the seat/crank relationship.

Thus, a bike that's a little too big will generally handle better than one that's a little too small.

Kimmo

I don't have that issue...



Ignore the seat angle, I'm a weirdo (although I see @Soody is too). Hmm, perhaps conformity is so rife that it's actually better for most, rather than a few, to point the seat the bars rather than have it level...?

Anyway, compare the position on that bike which is too small for me, to this one where my bike is on the large side.



And this one's my size.



As for the oddball bar/lever setup, I explained it here.

Brian Ratliff

As people have said, the downside is handling. If hands are too far in front of the wheel axle, you'll find your steering weird, especially if you get out of the saddle.

That said, the key measure is not stem length, but where your grip is relative to the front wheel axle (point of contact of the tire with the ground). Too far in front and you'll steer when you are trying to go straight standing out of the saddle, and the bike will feel sluggish when you actually do go to turn. Too far behind and when you stand, you'll get a "wheelbarrow" effect where your bike will try to steer the opposite direction of your weight when you stand on the pedals; when you go to turn, your bike will be exceptionally twitchy.

Choose a stem where your main grip on the drops is at your front axle, +- about an inch. There are really no hard and fast rules, but if your grip fall outside this range, maybe think about finding a different size frame.

Inpd

+1 Thanks Brian for a most informative post!

Soody

A saddle tilted down is good for a bike with a big saddle- bar drop that is ridden for less than 2 hours at a time.

I reckon you'd see it a lot, especially in TTs, if there wasn't a silly UCI rule. They just use noseless saddles instead i guess.

Cool bike, but you're wasting that lever. Why not hook up a bell or something.

Lazyass

Frame A will ride a hair stiffer since it's smaller and will handle a little slower. And of course the stem will be set higher. A slower steering bike isn't necessarily a bad thing. I heard Phill Ligget mention once that the guys in the pro peleton, and especially sprinters, tend to run longer stems because it makes their bike more stable and less twitchy in the pack.

Mark Cavendish's bike with a 140mm stem:

Sy Reene

Of note, you could/should have opted to create some of the seat-to-bar distance by opting for a seatpost with some offset.

wphamilton

For perspective, let's keep in mind that the differences here, in weight distribution and steering motion, are very small. While there is some impact on handling, having your reach off by an inch has more effect than an inch longer stem with the right reach.

YMMV but it is easy to see how a shorter stem would change the handling on your bike - just move your hands back from the hoods an inch and ride like that for a while.