Speedo Gears

55 vs 60 is a small error, around 9%. Simply pull your gear out, count the teeth, and just get one with one with 9% less teeth. That will be as close as you'll ever get it.

Actually, on second thought, first verify that your speedometer is reading low. I think that's what you are saying in the O.P. To be exact, you'll need a gear 9% smaller if you want the speedometer to speed up. .