The 235/55R18 is a common tire size for SUVs and crossovers such as Toyota RAV4, Honda CR-V, and Ford Explorer.
With a 129.3 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 +7.0% — a speedometer calibrated for 235/45R18 would read 93.4 km/h at an actual 100 km/h.
Fitted to mid-size luxury crossover base trims and similar SUV platforms. Load index 100V or 104H reinforced. Crossover-oriented; replacement compounds are mostly grand-touring with limited UHP options.
Crossover and mid-size SUV sizes carry significantly higher loads than passenger-car sizes of similar width, so the load index — not just the speed rating — is the spec to verify on replacement. Reinforced (XL/RF) versions are commonly OE; downgrading to standard-load risks sidewall failure on cargo-laden highway runs. Tread-pattern selection (H-T vs A-T) drives most of the noise and wet-grip difference.
| Tire Code | 235/55R18 |
| Section Width | 235 mm |
| Aspect Ratio | 55% |
| Rim Diameter | 18" |
| Sidewall Height | 129.3 mm |
| Overall Diameter | 715.7 mm / 28.18" |
| Circumference | 2248.4 mm / 88.52" |
| Revolutions per km | 444.8 |
| Revolutions per mile | 715.8 |
| Tire Code | OD (mm) | Δ mm | Δ % | Speedo at 100 km/h |
|---|---|---|---|---|
| 235/40R18 | 645.2 | -70.5 | -9.9% | 110.9 |
| 235/45R18 | 668.7 | -47.0 | -6.6% | 107.0 |
| 235/55R17 | 690.3 | -25.4 | -3.5% | 103.7 |
| 235/55R18 (current) | 715.7 | — | — | 100.0 |
| 255/55R18 | 737.7 | +22.0 | +3.1% | 97.0 |
| 235/55R20 | 766.5 | +50.8 | +7.1% | 93.4 |