A collection of formulas for gearing calculations
Formuals use exact measurements (ISO) instead of nominal sizes, which may be more conventional. This provides better accuracy, but may result in values that are higher or lower than what you expect.
- development
- gainRatio
- gearInches
- gearRatio
- skidpatches
- speed
Wheels include ISO and nominal sizes.
- chainrings (20T-64T)
- cogs (8T-36T)
- cranks
- wheels (from Sheldon Brown's data)
MIT 2015 Nic Haynes.