Tire size & gearing

Compare diameters, then re-gear to hold the old rollout.

Diameters & gearing

Current tire diameter

New tire diameter

Current pinion

Current total FDR

Two tire sizes are enough to compare. Pinion and total FDR are optional, for gearing corrections. Motor RPM and growth are held fixed.

Calculated relationship

Enter two positive tire diameters.

Kinematic comparison only: no growth, loading or real speed. Pinions need their own fitment check. Applying a change clears the GPS input.