Tyre Size Converter — ETRTO to French/Imperial
Convert between ETRTO, French and imperial tyre size designations.
622 = 700C, 584 = 650B, 559 = 26 inch
How We Calculate This
Size Conversion
Outer Diameter = Bead Diameter + (2 x Tyre Width)
Circumference = Outer Diameter x pi
ETRTO is the definitive size standard. The French name (e.g. 700x25C) maps to ETRTO based on bead diameter: 622mm = 700C.
Frequently Asked Questions
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Last updated: 2025-02-20
All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.