2 teeth can make a big difference in either direction. When you calculate your gear inches, think smaller number, easier to pedal, but you must pedal faster to go fast. Scrod here sells cogs for $16 plus $2 shipping, which is pretty reasonable and are good cogs. You could try out a couple and see what you want. I use 700c x 32 tires which gives me 42/16 (71 GI) and 42/18 (63). I had run 42/16 (liked), but knees were hurting, so I tried out 45/18 (67) for a few days and knees still hurt. Last couple of days I went back to 42/18 and have focused on spinning. Knees do not hurt right now.

Doc said the area behind my patella is shot on both knees, so I have to watch it.


Tom