Tire Size Calculator

Enter a tire size (e.g. 225/45R17) to get its diameter, circumference and revolutions per mile or km.

Formula

Diameter = (Rim diameter × 25,4) + 2 × (Tire width × Aspect ratio (%) / 100)

Assumptions

Enter a tire size (e.g. 225/45R17) to get its diameter, circumference and revolutions per mile or km.

How to read it

Overall diameter sets ride height and speedometer calibration. Revolutions per km are the easiest way to compare two fitments: the closer the values, the more transparent the swap.

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