RC Gear Calculator Pro

Easily calculate your gear ratio, final drive ratio, or rollout. Enter your gears "before and after" to see the real impact of your gear and tire changes. See the impact as a percentage (e.g. +2.5%), so you'll know how much speed and load on the motor to expect. Great for all types of RC racing and bashing, including on-road, off-road, oval, drift, speed runs, and more.
Aside from the primary ratio (spur:pinion), you can also see your Final Drive Ratio (useful for all cars, but definitely for touring cars) and Rollout (useful for cars with foam tires such as pan cars, F1, oval, and 1/28 scale.)
FEATURES
- Enter current gears and new gears to see both ratios and the percentage change
- Enter internal ratio to get the before-and-after Final Drive Ratio (FDR)
- Internal ratio for hundreds of cars built-in and updated regularly
- Enter before-and-after tire radius to get changes in rollout
- App remembers your entries, so you don’t need to retype them every time
- Detailed Help page describing ratios and how to use them