At age 73, I've recently taken my Bianchi Pista off the wall, where it has been hanging for a long time, and done two 25 mile rides on 48X18 or 69 gear inches, which is the gearing I used to use during winters in my youth in England. I find I spin out at 23.5 mph, so I might go to 71 inches, 48X17 to be better able to contest the occasional sprint with our group of oldies. It certainly is a pleasure to ride a fixed gear again.