How It Works
Diameter(mm)=rim(in)×25.4+2×width(mm)×aspect/100. Actual speed=indicated speed×new diameter/original diameter.
Nominal unloaded geometry only; tire load, wear, construction and inflation change rolling circumference. Fitment, clearances and load/speed ratings require separate checks.
Reference Sources
FAQs
How does this calculator work?
Diameter(mm)=rim(in)×25.4+2×width(mm)×aspect/100. Actual speed=indicated speed×new diameter/original diameter.
What assumptions should I check?
Nominal unloaded geometry only; tire load, wear, construction and inflation change rolling circumference. Fitment, clearances and load/speed ratings require separate checks.