Ratio Calc!

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 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 combinatio