Calculate RPM v Speed and Speed v RPM for your motorcycle. Determine your ideal gearing for the racetrack and road or check your speedometer error for your new sprockets and tyres.

Compare up to three different combinations of sprocket and tyre sizes at a time.

Select from thousands of included motorcycle models and build-years, from most popular manufacturers, or create your own custom setup.

Sprocket Doctor supports measurements in metric and imperial units and accepts all radial tyre sizes or actual tyre circumference measurements.

Sprocket Doctor produces detailed tables for each gear at 100rpm or 5kmh/mph intervals.

Best of all, Sprocket Doctor travels with you wherever your iPhone does, so you can fine-tune your gearing between track sessions or work on your ideal highway gearing in the middle of a ride.