Gear ratio is a fundamental concept in RC car performance, balancing acceleration, speed, and torque.
Internal Drive Ratio refers to the gear reduction inside the transmission or drivetrain before reaching the final wheels. It is determined by the car’s built-in gearing (e.g., differential and internal gearbox).
Final Drive Ratio (FDR) considers both the pinion and spur gears plus any internal reductions. It is calculated as:
FDR = Internal Ratio × (Spur Gear Teeth/Pinion Gear Teeth)
This number gives a better idea of how the overall system behaves. Higher gear ratios are useful for heavier cars or off-road vehicles that need more torque to move efficiently. Lower gear ratios are better for high-speed racing, where acceleration is less important than maintaining maximum velocity.
