carmath
Wheels & Tires

Tire Size & Speedometer Calculator

Calculate tire diameter change and speedometer error when switching to different tire sizes. Perfect for lifted trucks and modded vehicles.

Original Tire Size

mm
%
in

Example: 265/70R17 → Width: 265, Aspect: 70, Wheel: 17

New Tire Size

mm
%
in

Quick Presets

Results

Enter tire sizes and click Calculate to see results