FDR & rollout

Compare travel per motor revolution before picking a motor.

Drivetrain inputs

Pinion & spurTotal FDR

Pinion teeth

Spur teeth

Internal reduction

Outside rolling diameter

Internal reduction is everything after the pinion and spur. A supplied total FDR is used once.

Enter positive gearing and tire diameter. Pinion and spur must be whole tooth counts.

More rollout means taller gearing, and more load and heat. Nearby sizes are arithmetic, not fitment or availability checks.