Road Cycling - TT length question

Just what exactly does TT length do for the ride? In other words, would a 57cm TT with a 110mm stem ride any different than a 58cm TT with a 100mm stem?

Slightly quicker steering on the latter version I guess, because of the shorter stem, but any other differences?

Interesting question, I will also wait to hear this answer.

a related question might also be: what is the ideal stem length range for optimum steering, stability or whatever

Argonne... It depends on your body proportions. If you have long legs but a short torso, a long TT could cause you much pain and discomfort; if you have a long back, it could be the answer to your dreams. For most people, it provides a more relaxexed, flat-backed position, and moves the centre of gravity backward from the forks [relative to a shorter TT] for more stable handling.

Guillermo: I don't think there's an OPTIMUM stem length, but I think you'd be sacrificing a lot of responsiveness going with a stem longer than, say, 12 cm and sacrificing stability with one less than 9 cm. Of course, this is all relative to the size of the bike -- a 14 cm stem on a 60 cm TT wouldn't be as bad as a 14 cm stem on a 52 cm TT -- and the body proportions of the rider.

To expand just a bit on Velocipedio's reply, I believe that, all other things being equal, a longer top tube would suggest a longer frame overall so a little more flex, shock absorption, and comfort as a result. A shorter frame should be stiffer and more responsive. For this reason, touring frames are generally longer, racing frames shorter, all within the parameters of overall fit, of course.

Gimme a break.

Argonne wasnt asking about a short reach bike vs a long reach bike, but 2 bikes of identical reach, the reach made up in 2 different ways.

The only guide I have seen to match stem length to TT length was in the book Touring Bikes by Tony Oliver. He tried to match them proportionately using his long experience, and used a standard medium bike (56cm T 10cm stem) as a guide. Bikes built this way just look right, and if it looks right, it generally rides right.
A long TT/short stem would have twitchy steering
short TT/long stem may have toe-clip overlap or sluggish steering.

Originally posted by pokey
Gimme a break.

Huh? :confused:

I assume you are talking about a road bike here. On mtbs the top tube is longer than a road frame, to give you more room to move about when you are out of the saddle doing mad stuff, jumps and the like.
On a road bike, your position shouldn't be so stretched out, your arms should be at 45 degrees when riding on the tops and your back should be flat when you crouch down on the hooks. Too long a TT and you will put strain on your back. Most decent off-the-peg road frames will have a TT in proportion to the seat tube length, so get this right and the rest should follow.