Originally Posted by
Steve B.
Gear inches is how far the bike travels with every 360 degree revolution of the crank.
Not quite, although the values are related. Since "gear inches" gives you an equivalent wheel diameter, if you want to figure out how far the bike travels with one crank revolution, you have to multiply by pi to convert the diameter into a circumference. So with 100 gear-inches, the bike will travel (100 * pi = ~314 inches) with each revolution of the crank.