Garage tool
Gearing calculator
Two setups, side by side. Type or step the teeth and everything updates instantly.
Pick a bike to fill both setups with its stock sprockets.
Front sprockets 8–16 teeth, rear 34–60. Values outside that range are brought back to the nearest limit.
Setup A — what you run now— — : 1
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Changing the rear sprocket changes the chain length too. The chain length calculator works it out from the chain you have now, with where the axle ends up.
Ratios are exact. The chain figure is an estimate of roughly one link per two teeth of change — confirm against your manual before ordering.
How to read it
Final drive ratio is rear teeth divided by front teeth. A higher number is shorter gearing: quicker to pull, lower top speed.
Pull at the wheel and top speed are the percentage change from Setup A to Setup B. They move in opposite directions by the same proportion, because gearing trades one for the other — it doesn’t create power.
Chain is an estimate only, at roughly one link per two teeth of change. Whether you actually need a different chain depends on your axle position and adjuster range, so check the manual and your current chain slack before ordering.
One tooth on the front sprocket changes the ratio far more than one tooth on the rear. If a change feels too big, try the rear first.