GearInch is a bicycle gear inch calculator for your phone. Use it to find the cog and chainwheel sizes of your desired gear-inch ratio, or to figure out the gear-inch ratio of components you already have.
*Input exactly your wheel size! Support for 650c/700c/20", 24", 26" and 29"(same as 700c) wheel sizes.
*Precise calculations! Calculations include tire width.
*Mountain and road bike tires supported! Tire width input in both inches and mm for mountain and road bike tires.
*Convert in both directions! Input cog and chainwheel sizes to determine their ratio, or see equivalent combinations for an input ratio.