A bike's gear ratio is the front chainring teeth divided by the rear sprocket teeth — how many wheel rotations you get per pedal stroke. A 50-tooth ring with a 14-tooth cog gives a 3.57:1 ratio. Multiplied by wheel circumference it gives 'development' (distance per pedal revolution). Higher ratios mean more speed per stroke but are harder to push; lower ratios make climbing easier.
Key points
- Chainring teeth ÷ sprocket teeth
- Wheel turns per pedal revolution
- Higher = faster but harder to push
- Lower ratios ease climbing