RC Car Gear Ratio Calculator
Gear Ratio & Rollout
Calculate final drive ratio and rollout from pinion, spur, and internal ratio
Find Pinion for Target Speed
Calculate which pinion gear to use for a target top speed
Formula
Final Drive Ratio = (Spur / Pinion) × Internal Ratio
Frequently Asked Questions
What does gear ratio mean in RC cars?
Gear ratio is how many times the motor turns for one wheel rotation. A higher ratio (e.g., 12:1) gives more torque and acceleration. A lower ratio (e.g., 6:1) gives higher top speed.
How do I change my RC car's gearing?
Swap the pinion gear (on the motor shaft). A larger pinion = lower ratio = more speed. A smaller pinion = higher ratio = more torque. Always check motor temperature after changing gearing.
What is rollout?
Rollout is the distance the car travels per motor revolution. It combines gear ratio and tire size. Higher rollout = more speed but less acceleration.