RC racers today are always looking for an edge, and sometimes that even included changing the size of the rotor in their brushless motor.
Motors with large rotor diameters give more torque, while smaller diameter gives more top speed.
Smaller rotor diameter
- Less torque
- Higher rpm (top speed)
- Ideal for on-road, especially 1/12th scale
Larger rotor diameter
- More torque
- Typically required in spec classes
- Require tall gear ratios (large pinions) to get speed