Tyre Size Calculator
Decode a tyre size like 225/45R17 into overall diameter, sidewall height, circumference and revolutions per mile.
Enter your values and press Calculate.
How to use the Tyre Size calculator
In 225/45R17: 225 mm wide, sidewall 45% of the width, R = radial construction, 17″ wheel.
Formula
Sidewall = width × aspect ratio ÷ 100 (mm); diameter = rim + 2 × sidewall.
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