The 255/55R18 is a common tire size for SUVs and crossovers such as Toyota RAV4, Honda CR-V, and Ford Explorer.
With a 140.3 mm sidewall (55% aspect ratio), this tire offers a balanced blend of ride comfort and handling precision — versatile for both city driving and spirited cornering.
Compared to the baseline 235/45R18, this tire's overall diameter differs by +10.3% — a speedometer calibrated for 235/45R18 would read 90.6 km/h at an actual 100 km/h.
When replacing, verify that your wheel well can accommodate the 737.7 mm overall diameter. Keep speedometer deviation within ±3% for safety and legal compliance.
| Tire Code | 255/55R18 |
| Section Width | 255 mm |
| Aspect Ratio | 55% |
| Rim Diameter | 18" |
| Sidewall Height | 140.3 mm |
| Overall Diameter | 737.7 mm / 29.04" |
| Circumference | 2317.6 mm / 91.24" |
| Revolutions per km | 431.5 |
| Revolutions per mile | 694.4 |
| Tire Code | OD (mm) | Δ mm | Δ % | Speedo at 100 km/h |
|---|---|---|---|---|
| 255/40R18 | 661.2 | -76.5 | -10.4% | 111.6 |
| 255/45R18 | 686.7 | -51.0 | -6.9% | 107.4 |
| 235/55R18 | 715.7 | -22.0 | -3.0% | 103.1 |
| 255/55R18 (current) | 737.7 | — | — | 100.0 |