[SenorBlanco]

OK, so there will be subtle differences in quickness of steering due to leverage differences between the stem lengths, but is there any real difference between the following setups:

1. 58cm top tube with 100mm stem
2. 56cm top tube with 120mm stem

I come from a mountain bike background, and ride a 6" travel bike with slacker geometry. The ultra quick steering of a road bike makes them feel really twitchy to me. So would I be better going with the 58cm frame and shorter stem since it should slow down the steering a bit?

 

[JayTee]

Both are reasonable approaches to the same issue (overall reach). The main issue with the 56 is bar height/headtube length. Are the bars too low once you get the saddle where you want it? If not, I'd absolutely recommend the 56.

 

[texass4]

In short, yes, a shorter stem will ease the steering twitchiness most of the time. However, that;s just one small piece of the puzzle.

How tall are you? There are many other variables to consider body-wise (leg length proportional to torso length) and of course differences in frames between manufacturers...no all frames of one size will fit the same. Some bikes (of a comparable type) are a more aggresive ride than others. give 'em all a test ride.


In my opinion, the first and most basic question is: which bike (58 or 56cm) provides the best standover height. You have a MTB background, so that's nothing new for you, but if twitchy steering is your main concern, I'd say that the best way to sort it out is to choose a bike that fits with minimal "fudging" of parts to make it work (i.e. as close as possible to a natural fit) and ride. The first few outings on a road bike may give you a sore neck and leave you a little unsteady with the quick steering coming from MTB. After awhile, it will seem natural and your MTB will feel slow - in a good way in that you are more able to nail any line that you want through the trails.

 

[StormShadow]

In short, yes, a shorter stem will ease the steering twitchiness most of the time.

You have it backwards. Shorter stem = faster steering. Longer stem = slower steering.
That being said, I would go for the 57cm with a 100mm stem.

 

[Cory]

My years on too-small bikes say "Go big."

You'll get used to the steering quickly either way. I've had stems from 150cm down to 60cm on one of my bikes (old MB I used as a commuter for awhile; I wanted to sit up straighter for better vision), and it takes about 10 feet to get the feel of it. You're not going to veer off the road or anything.
As for frame size, I'm a Clyde, and for 20 years I rode what the bike shops sold me, because 62 cm was the biggest frame most places stocked. When I got my Atlantis, Rivendell's sizing chart put me between a 64 and 65, three cm bigger than my biggest previous bike. They were out of 65s, so I got the 64, and it made a big, immediate difference in comfort. I could stay on the bike at least 25 percent longer (the B-17 saddle probably helped...), and I set PRs (in my late 50s) for several longish rides I do often.

 

[SenorBlanco]

You'll get used to the steering quickly either way. I've had stems from 150cm down to 60cm on one of my bikes (old MB I used as a commuter for awhile; I wanted to sit up straighter for better vision), and it takes about 10 feet to get the feel of it. You're not going to veer off the road or anything.
As for frame size, I'm a Clyde, and for 20 years I rode what the bike shops sold me, because 62 cm was the biggest frame most places stocked. When I got my Atlantis, Rivendell's sizing chart put me between a 64 and 65, three cm bigger than my biggest previous bike. They were out of 65s, so I got the 64, and it made a big, immediate difference in comfort. I could stay on the bike at least 25 percent longer (the B-17 saddle probably helped...), and I set PRs (in my late 50s) for several longish rides I do often.

I tend to agree. I settled on a 58cm frame. It currently has a 120mm stem on it, but I do feel a bit stretched out on that. I could certainly live with it, but I think a 100mm would be perfect so I'm going to give that a try. The standover and top tube lengths of the 58cm feel better to me. I feel a bit cramped on the 56cm with 120mm stem, so I went with the 58cm.

Now I've just got to get used to the positioning for long periods of time, quite different than my mountain bike.