Originally Posted by bitpartinyrlife
Gear inch numbers are higher than than values I got from Sheldon Brown's calculator using 700c wheels. What gives?
It's based on 27" wheels and the oldey-timey formula: # of chainring teeth * 27" / # of cog teeth.
Gear inches are really only useful as a rough, relative measure (ie, comparing ratio to ratio), so it doesn't really matter that you're getting slightly different measurements. Measuring by gear inches also fails to take crank length into account.
m.