Drivetrain calculators
Work from engine RPM to the road with transparent gearing math.
Gear ratio & speed
Calculate theoretical road speed and wheel RPM from engine RPM, total drivetrain reduction and tire diameter.
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Sprocket ratio
Calculate chain sprocket reduction and compare a proposed driven sprocket with the current setup using percentage gearing and speed changes.
Open calculatorFinal drive ratio
Divide driven teeth by driving teeth to calculate chain or ring-and-pinion final reduction, then compare a proposed driven tooth count.
Open calculatorRPM to MPH
Convert engine revolutions per minute into road speed using tire diameter and overall reduction. See MPH, KPH and wheel RPM together.
Open calculatorRatio from RPM
Infer overall drivetrain reduction from measured engine RPM, road speed and tire diameter under steady, no-slip conditions.
Open calculatorTire size & gearing
Find the reduction needed to preserve engine RPM per road speed after a tire-diameter change, plus the gearing effect if the axle ratio stays the same.
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