Formula & method
Relative to the hub mounting face: inner = width/2 + offset; outer = width/2 − offset.
Example
9 in ET25 → inner nominal edge 139.3 mm, outer nominal edge 89.3 mm.
Limitations
Calculated dimensions are nominal values based on tire-size notation; actual measured dimensions vary. These calculators compare nominal tire and wheel geometry. Actual fitment depends on the vehicle, wheel, tire model, suspension, brake clearance, load/speed ratings and local requirements. Verify final fitment before purchase or installation.