RC Car Gear Ratio Calculator

The RC Car Gear Ratio Calculator helps RC car owners understand how pinion, spur, transmission, differential, and tire changes affect the final drive ratio. Gear ratio is one of the first setup choices that changes acceleration, top speed, motor load, ESC temperature, and battery demand.

What this calculator does

A taller gear ratio may look faster on paper, but it can also push the motor out of its efficient range or overload the battery. This calculator is useful for bashers, speed-run cars, touring cars, drag cars, and any electric model where gear changes are part of tuning. Enter your pinion, spur, internal ratio, and tire values to compare setups before making the change. Example: a driver can calculate the difference between a 34/46 and 39/46 setup, then use the speed or battery calculators to check whether the extra load is realistic. It is a simple supporting tool that helps make the more advanced RCexplained speed and battery calculators more meaningful.

In practical terms: It calculates gear ratio and related drivetrain values so you can compare gearing changes before testing them on the vehicle.

How to use it

Enter the pinion, spur, internal drive ratio, and tire size. Change one value at a time to see how the ratio moves.

Example calculation

Compare two pinions with the same spur gear to see how much taller the setup becomes before checking motor and battery load.