255/55R18 tire size
A 255/55R18 tire is 255 mm wide with a sidewall 55% of its width (140.2 mm), fits a 18-inch rim and has an overall diameter of 738 mm (29.0 in).
| Dimension | Metric | Imperial |
|---|---|---|
| Section width | 255 mm | 10.04 in |
| Sidewall height | 140.2 mm | 5.52 in |
| Rim diameter | 457.2 mm | 18 in |
| Overall diameter | 737.7 mm | 29.04 in |
| Circumference | 2,317.6 mm | 91.24 in |
| Revolutions | 431 per km | 694 per mile |
Reading the size 255/55R18
255Width in mm55Aspect ratio (sidewall % of width)RRadial construction18Rim diameter in inches
The load index and speed rating (for example 91V) follow the size on the sidewall. Replacement tires should match or exceed the original load index and speed rating.
Alternative sizes within 3% of 255/55R18
A replacement size should stay within about 3% of the original diameter so the speedometer, ABS and transmission stay accurate. Always check clearance, load index and the vehicle manufacturer's approved sizes.
Compare 255/55R18 with any size →