Derailleur icon Derailleur download QR code


by A. H. de Quatre Ltd.
iPhone Utilities Requires iOS 15.2


About Derailleur

Winner of the Apple WWDC22 SSC

--- Trusted by pro teams ---
--- and 5000+ users worldwide ---

Derailleur lets cyclists quickly and easily estimate their speed at different cadences depending on their bicycle setups. Designed to be the best and easiest-to-use app for calculating gear ratios and skid patches, Derailleur combines precise calculations with an intuitive design, so that changing a bicycle setup is quick and simple.


• Find your cadence sweet spot — The gear ratio on a bicycle can be optimized for different terrain, riding styles and fitness levels.

• Extend the lifespan of your tyres — Fixed gear cyclists will benefit from spreading their skid patches evenly around the rear tyre.

All calculations provided are merely for educational and informational purposes. It is not a substitute for professional advice from your local bike shop.