Ratio Calc is a quick and easy tool for radio control car racers to use trackside. Knowing your final drive ratio (FDR) is very useful for comparison with other racers to determine if your car is geared correctly.

It lets you quickly select your car by filtering on class, manufacturer and model. Select your pinion and spur size and the FDR is displayed. Tyre diameter can also be entered to calculate your rollout.

Ratio and roll out charts are also available which plot pinion and spur gear combinations to create very handy reference tables.

- Save your favourite cars for quick access

- Save notes and track name against your favourite cars

- Send ratio charts via email

- Suggest new cars from within the app

- Download new cars from within the app at the click of a button

- Select measurement units (imperial/metric) via Settings

- Select your preferred gear pitch, alternative ratios in other pitches will be shown

- Currently over 940 cars/variants in the database