Motorcycle Sprocket Gearing, RPM & Tire Size Speedo Calculator
Load any motorcycle from our database to pre-fill factory sprockets, rear tire profile, peak RPM, and top speed—then test -1T / +2T sprocket mods or rear tire profile changes (e.g. 180/55-17 → 190/55-17) in real time.
Front Sprocket
Rear Sprocket
Rear Tire Size Change
Calculated Drivetrain & Speedo Telemetry
Stock vs. Modified Output
Final Drive Ratio
Wheel Torque / Thrust
100 / 120 km/h Top-Gear RPM
Geared Top Speed
Transmission-Pickup Speedometer Error & Tire Diameter
When your countershaft-driven speedometer reads 100 km/h, your true GPS road speed is ().
* Modern ABS wheel-ring bikes only experience speedo error from tire circumference changes, not sprocket swaps.
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