Motorcycle Chain-Drive Gear Ratio Calculator

LIGUORI DRAG RACING

Compare your chain-drive gearing

Enter the front and rear sprocket tooth counts. Adjust the proposed setup to see the final-drive ratio and percentage changes instantly.

Current setup

Proposed setup

Front means the countershaft sprocket; rear means the sprocket on the rear wheel. Starting values are an example—replace them with your motorcycle’s setup.

PROPOSED FINAL-DRIVE RATIO — REAR ÷ FRONT
—:1
—Current final-drive ratio
—Ratio / ideal torque change
—Speed change at the same RPM

Try nearby sprocket combinations

Changes below are compared with your current setup. Select a combination to try it.

Front Rear Ratio Ratio change Try it

Final drive = rear sprocket teeth ÷ front sprocket teeth. A higher ratio is shorter gearing; a lower ratio is taller gearing. Ideal rear-wheel torque and engine RPM at the same road speed scale with the ratio when the selected transmission gear and tire circumference stay the same. Road speed at the same engine RPM changes inversely with the ratio. These percentages do not predict acceleration, elapsed time, traction, or actual top speed.

Sprocket fitment, chain clearance, and available adjuster travel still need to suit the motorcycle. Changing sprockets can also change the required chain length.

Check chain length →
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