This is a simple and fast tool to determine the gear-inches, speed and cadence (RPM) of various chainring, sprocket, and wheel-size combinations on track racing bikes. It is also suitable for other single-speed bicycles. It includes options for traditional track calculations, or exact results, and your speed in either miles (MPH) or kilometers (Km/h). Does not require an Internet connection.

To use, simply enter the number of teeth in your bike's chainring (the gear by the pedals) and your sprocket (the gear on your rear wheel). This calculates your gear-inches; bigger numbers represent taller gears. You may also elect to enter either your actual speed, which calculates your approximate RPM (cadence), or your actual RPM, which calculates your approximate speed.

The default settings calculate traditional track-racing gear-inches, which are based on a standard 27-inch tire size. But you can also elect to calculate the gear-inches for any specific tire size you choose, by measuring the circumference of your tires in millimeters: 2096 mm is typical for 700x23c tires, for example.