Hi all. I have a 58 cm Surly Cross Check, which seems to fit pretty well, generally. However, I'm hoping to shift my weight forward a bit more, and I'm thinking of moving my stem down to do it. The head tube angles is very slack, so it seems that taking the stem down a spacer or two will also shift it forward pretty dramatically. Will that accomplish shifting the COG forward as well? Any downsides? Thanks!

Your torso will be closer to horizontal which will shift CG forward a little, not that much. No harm in trying.

Thanks! The reason I ask is that I appear to be putting too much weight on my saddle, causing the rails to bend. (While no delicate flower, I'm well under the weight limit for the saddle; the manufacturer has suggested it could be an issue with weight distribution.) Because the Surly is relatively slack in its head and seat tube angles, I thought shifting the stem down might address the issue.

I'd agree with jyl... there will be some forward shift of COG, but maybe not enough to help the saddle. You might end up with neck and shoulder issues, or you might not. It is not generally recommended to try to increase the weight that your shoulders and arms are supporting.

I'm curious, though: where is your seatpost attached to the saddle? Is the saddle all the way back? Centered? If the saddle is all the way back, that can certainly generate very large bending stresses on saddle rails. Especially if you stay firmly in the saddle for rougher parts of riding.

Has anyone looked at your fit? Saddle could be too low or too far forward/back, handlebars could be high, maybe riding style is part of the problem. But, it will be easy to test the setup.

You may find you change several things. For example, you will probably have to change saddle tilt if handlebars come down. You might want to take measurements of saddle height, setback, saddle to handlebar reach, handlebar height and note changes as you experiment.

Turn the seat post around so you are further forward Its a Tri Bike Thing..

Thanks, all!