Tyre size decoder
Every number and letter on your sidewall means something specific. Paste your size below and we will explain all of it in plain language.
Common questions
What do the numbers on a tyre mean?
In a size like 225/45R17, 225 is the tread width in millimetres, 45 is the sidewall height as a percentage of that width, R means radial construction, and 17 is the wheel diameter in inches. Numbers after that are the load index and speed rating.
What does XL mean on a tyre?
XL means Extra Load — a reinforced casing able to carry more weight at a higher inflation pressure. If your vehicle specifies XL, a standard-load tyre of the same size is not a valid substitute, because it cannot legally carry the same weight.
What is the load index on a tyre?
A code representing the maximum weight each tyre can carry. Index 94, for example, means 670 kg per tyre. Never fit a lower load index than your vehicle specifies — on a heavy SUV that is a genuine safety issue, not a technicality.
What does the speed rating letter mean?
The maximum sustained speed the tyre is built for. W is 270 km/h, V is 240 and H is 210. It is also a heat-tolerance rating, which matters here: sustained high-speed running in 45°C ambient heat is close to what these ratings actually describe.