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Chain and Sprocket Calculator
Gear Ratio and RPM to MPH Calculator with Auto Shift and Tracer   Enter Gear and Diff Ratios and drag RPM Slider
See also: Printable Full Scale Degree Wheels Dial in your cam - and Printable Timing Tape

Enter Diff + Gear Ratios and tire diameter, then drag RPM slider to calculate speed from RPM. Drag Max RPM slider to adjust the range of the RPM and MPH Gauges.

Enter Shift at RPM, select gear to shift to and hit Auto Shift to run up through the gears recording shift point RPM and MPH.

For motorcycles, check Sprockets and enter Primary Drive Ratio and front and rear sprocket tooth count to calculate final drive ratio.

Set current entries as default on page load.

Add popular transmissions Please Let us Know the transmissions you'd like to add to the Select Transmision list.

RPM gauge diagram MPH gauge diagram


Start Gear 1
Tire Diameter in
Calculate Tire Diameter

Primary Drive
Final Front
Final Rear
Shift →
Slow Fast

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Gear ratio graph diagram

Gear ratio RPM shift point graph diagram

Shift →


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Don't cut it, or cut it wet so there's NO DUST - Silicosis Sucks

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Check relevant local regulations for appropriate sizes, spacings and all engineering requirements.

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