Tyre size converter

Type whatever is written on your sidewall. Everything converts through ETRTO, because the inch and French markings are trade names and two of them famously do not fit the same rim.

How to measure this

3 steps

1Find both markings

Nearly every tyre carries two sizes. The trade name is the big one; the ETRTO pair is usually smaller and near the bead.

Tyre marking

700x28c, 29x2.4, 28-622, 650b x 47 — any of these.

Rim compatibility

Internal rim width

Between the bead walls, not across the outside of the rim.

This tyre is narrow for the rim. The casing gets stretched into a light-bulb profile that handles poorly and is easy to damage.

This rim takes

30–50mm

Likely measured width

28.8mm

A wider rim holds the same tyre wider, which matters for frame clearance.