The dimensions are stated on all car tyres. Example of designation:235/45R17 97W.
| 235 | Tyre width (mm) |
| 45 | Ratio between tyre wall height and tyre width (%) |
| R | Radial ply |
| 17 | Rim diameter in inches (") |
| 97 | Codes for the maximum permitted tyre load, tyre load index (LI) |
| W | Speed rating for maximum permitted speed, speed rating (SS). (In this case 270 km/h.) |
The car has an approval for the complete vehicle with certain combinations of wheel rims and tyres.