Tyres come in all sorts of sizes from big fat treaded mountainbike wheels to tiny 19mm wide 220psi tubulars for the racing chairs.

We have listed the tyres by type and then size. Have a look at the sidewall of your existing tyre. This should have a number (called the ETRTO number) in the format xx-xxx written. The first number is the approximate tyre width, the second is the diameter of the rim/tyre seat, both in millimeters. As you will see, there are often more than one actual tyre size in any nominal size, for example, a 26" tyre can be 3 different measurements (559mm, 571mm and 590mm in diameter) depending on which sizing series it originates from, so always check the ETRTO number before ordering.

For more information on wheel and tyre sizing have a look at this page.