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Dirt Bike Tire Size Calculator

Decode a size like 80/100-21 or 110/90-19 into diameter, sidewall, and circumference.

Inputs

The number after the slash

Results
Live

  • Overall diameter

    27.3in

  • Overall diameter

    693mm

  • Sidewall height

    80mm

  • Circumference

    85.76in

  • Size code

    80/100-21

Formula

Ø = rim + 2 × (width × aspect / 100) / 25.4 (Ø in inches)

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