Coolio!....another Soho-S rider I don't know if the stock rims will take a 32mm or larger tire. I'm contemplating a presta-valve wheelset in fix/fix....maybe run a 15 and a 17 (for when I'm far from home and my legs/knees start to stress). I like the 28mm tires. Its a good compromise for me between speed, compliance, and durability.....and no flats, so far in 500 miles. I pump the tires to 120psi before every ride. I weigh 250lbs and it doesn't feel harsh at all to me. I don't skid, but I try not to use the brakes as much as possible.

I just installed a 15t out back. A 44/15 = 79.2" gear instead of the stock's 44/17 = 69.9" gear. I was going to do a 48/17 = 76.2", but this was readily available and the LBS said the smaller chainring would be stiffer under power. The near 80" is not too crazy for my knees since most of my spinning is on relatively flat roads. Plus, I think it gives me a good feel of what to expect (gearing-wise) for when I pursue track classes/training/...uh...racing(?) next year....or sooner