Tyre size calculator
Tyre size equivalents
Enter your current tyre size. We list every size whose diameter stays within the 2 % tolerance, with the matching ETRTO rim widths.
Calculating tyre size equivalents
It is entirely possible to replace your original tyre size with an alternative size, especially if you wish to fit larger-diameter wheels for aesthetic or technical reasons. However, certain rules must be followed to ensure your vehicle's compatibility and safety. The difference in diameter between the original and the alternative tyres must not exceed 2 %, so that the speedometer and driver assistance systems continue to work correctly. A greater difference could lead to malfunctions, incorrect speed readings and even premature wear of vehicle components.
To make sure that the new tyre size respects this tolerance, you can use our tyre size equivalent calculator. This tool lets you check whether the chosen size complies with the recommendations and helps you choose tyres compatible with your new wheels, while keeping your speedometer accurate and your driving comfortable.
Rim / tyre width table
Our rim/tyre table lets you quickly find the tyre sizes compatible with different rim widths. Whether you opt for larger wheels for a sportier look or a smaller size for a more comfortable ride, it is essential to choose tyres of suitable dimensions. This table helps you make the right choice by ensuring that the rim/tyre combination respects the technical tolerances.
| Rim width | Minimum tyre width | Ideal tyre width | Maximum tyre width |
|---|---|---|---|
| 5.0″ | 155 mm | 165 or 175 mm | 185 mm |
| 5.5″ | 165 mm | 175 or 185 mm | 195 mm |
| 6.0″ | 175 mm | 185 or 195 mm | 205 mm |
| 6.5″ | 185 mm | 195 or 205 mm | 215 mm |
| 7.0″ | 195 mm | 205 or 215 mm | 225 mm |
| 7.5″ | 205 mm | 215 or 225 mm | 235 mm |
| 8.0″ | 215 mm | 225 or 235 mm | 245 mm |
| 8.5″ | 225 mm | 235 or 245 mm | 255 mm |
| 9.0″ | 235 mm | 245 or 255 mm | 265 mm |
| 9.5″ | 245 mm | 255 or 265 mm | 275 mm |
| 10.0″ | 255 mm | 265 or 275 mm | 285 mm |
| 10.5″ | 265 mm | 275 or 285 mm | 295 mm |
| 11.0″ | 275 mm | 285 or 295 mm | 305 mm |
| 11.5″ | 285 mm | 295 or 305 mm | 315 mm |
| 12.0″ | 295 mm | 305 or 315 mm | 325 mm |
| 12.5″ | 305 mm | 315 or 325 mm | 335 mm |
Wheel offset (ET) calculator
This calculator lets you determine the difference resulting from a change in offset (ET) or rim width, so that you can check compatibility with your vehicle. It helps you assess the possible differences in fitment and appearance.
Original wheels
Outside
Inside
New wheels
This information is provided for guidance only and does not engage Rupteur's liability in any way.