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Sprocket ratio calculator

Compare front and rear sprockets to see theoretical changes in final-drive ratio, engine RPM, wheel torque and road speed.

Compare current and new sprockets. No engine knowledge required.

Current sprockets

New sprockets

Engine, cylinder and carburetor

Kies je setup en vul eventueel je gemeten vermogen in. We berekenen het koppel en de theoretische snelheid met jouw echte gegevens, zonder willekeurige pk-schattingen.

Choose a cylinder to see setup and carburetor details. Power is not estimated.

Source of cylinder specifications

Your comparison

Current final-drive ratio—
New final-drive ratio—
Engine RPM at the same road speed—
Theoretical wheel torque—
Speed at the same engine RPM—
Theoretical speed for your example—

What does your setup do?

Engine torque at measured RPM—
Wheel torque with new sprockets—
Speed at measured RPM: old → new—

Koppel wordt alleen berekend met gemeten krukasvermogen en het daarbij behorende toerental. Wielkoppel en absolute snelheid vereisen extra overbrengingsgegevens. Dit is geen gegarandeerde topsnelheid.

Shop chains and sprockets

Theoretical changes at the same RPM; higher top speed is not guaranteed.

How does gearing work?

Final-drive ratio is rear sprocket teeth divided by front teeth. A larger front or smaller rear sprocket makes gearing taller.

Important

Results are theoretical. Real top speed depends on power, drag, gearbox and tires. Taller gearing does not guarantee a higher top speed. Check chain pitch, length, clearance and fitment. Not for CVT scooters.