Originally Posted by powerglide
My friends on the track are uber sensitive about gear ratios...gear inches was explained to me like this:
If my bike has a 6 gear inch difference compared to your bike, then our bikes will be 6 inches apart every revolution fo the crank.
Originally Posted by 55-11
Gear inches refers specifically, as stated previously, to distance traveled.
It doesn't quite work that way. "Gear inches" are not the distance travelled for each crank rotation. Gear "development" is the distance travelled. For development you need to multiply gear inches by pi (3.1416). The gear inch number is only good for comparing gear combinations. If one rider has a 110 gear inches and another rider has 116 gear inches and they are riding at the same cadence then the rider with the 116 is going 18.9 inches farther with each rotation of the crank.
110 X 3.1416 = 345.5 inches
116 X 3.1416 = 364.4 inches
364.4 - 345.5 = 18.9 inches