Formula & method
Actual speed = indicated speed × new circumference ÷ original circumference.
Example
If the new circumference is 2% larger, 100 km/h indicated corresponds to about 102 km/h actual.
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.