Wheel Speed Calculator

Ultimate Tire & Gear Ratio Calculator

Calculate tire diameter, sidewall height, circumference, revolutions per mile, and vehicle speed per gear using your tire size, axle ratio, RPM, and transmission ratios.

Vehicle Inputs

Accepted: 275/40R18, 275/40/18, 275/40ZR18, 275-40-18
Examples: 3.23, 3.55, 3.73, 4.10
Change RPM to see speed per gear.
Output Units
Transmission Gears

Tire Diameter Results

Diameter —
Diameter —
Sidewall Height —
Circumference —
Revs Per Mile —
Wheel Diameter —

Speed Per Gear

Enter your values. The table updates as you type.
Gear Ratio MPH @ RPM
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