33x12.50R18 in metric
| Measure | Inches | Millimetres |
|---|---|---|
| Overall height | 33.00 in | 838 mm |
| Width | 12.50 in | 318 mm |
| Sidewall | 7.50 in | 190 mm |
| Wheel | 18 in | 457 mm |
| Revs per mile | 611.2 |
Flotation sizes are written as height × width R wheel in inches, so 33x12.50R18 is 33 in tall and 12.50 in wide by definition. Metric sizes are written in millimetres, so there is no exact twin: these are the closest calculated metric sizes on a 18 in wheel.
Closest calculated metric sizes
| Size | Height | Off by | Width |
|---|---|---|---|
| 345/55R18 (compare) | 32.9 in | −0.06 in | 13.6 in |
| 295/65R18 (compare) | 33.1 in | +0.10 in | 11.6 in |
| 315/60R18 (compare) | 32.9 in | −0.12 in | 12.4 in |
| 325/60R18 (compare) | 33.4 in | +0.35 in | 12.8 in |
| 335/55R18 (compare) | 32.5 in | −0.49 in | 13.2 in |
These are calculated combinations of standard widths and aspect ratios, not a list of tires that are sold: confirm a tire is made in that size, and that it suits your wheel width.
Moving up to 33x12.50R18 from a smaller tire
| From | Height change | 60 mph on the speedometer is really | Verdict |
|---|---|---|---|
| 275/70R17 | +2.6% (+0.84 in) | 61.6 mph | Close match |
| 285/45R22 | +2.8% (+0.90 in) | 61.7 mph | Close match |
| 275/65R18 | +2.9% (+0.93 in) | 61.7 mph | Close match |
Regearing
A tire this size is taller than most stock tires, so engine RPM falls at a given speed. See the gear ratio calculator and the regear chart.
Calculated from the size alone. Real tires vary a little by brand and model, and the loaded radius is a bit smaller. Confirm the wheel width range, clearance, load index and speed rating for your vehicle. See how to read a tire size, the load index chart and the speed rating chart.