255/55R18 Tire Size
Dimensions of a 255/55R18 tire in inches and millimeters, with equivalent and plus sizes.
255/55R18 dimensions
A 255/55R18 tire is 255 mm wide with a sidewall that is 55% of the width (140 mm), mounted on a 18-inch rim. Its overall diameter is about 29.04 inches (738 mm), so it is roughly a 29.0-inch tall tire.
| Overall diameter | 29.04 in | 738 mm |
|---|---|---|
| Section width | 10.04 in | 255 mm |
| Sidewall height | 5.52 in | 140.2 mm |
| Rim diameter | 18 in | 457 mm |
| Circumference | 91.2 in | 2318 mm |
| Revolutions | 694 per mile | 431 per km |
Equivalent sizes on a 18-inch rim
These sizes stay within ±3% of the 255/55R18 diameter on the same rim — the range most tire shops use. Not every size is made in every tire model, and only sizes approved for your vehicle (with the right load and speed rating) should be fitted.
| Size | Diameter | mm | Difference |
|---|---|---|---|
| 235/60R18 | 29.10 in | 739 mm | +0.2% |
| 275/50R18 | 28.83 in | 732 mm | -0.7% |
| 245/55R18 | 28.61 in | 727 mm | -1.5% |
| 265/55R18 | 29.48 in | 749 mm | +1.5% |
| 245/60R18 | 29.57 in | 751 mm | +1.8% |
| 265/50R18 | 28.43 in | 722 mm | -2.1% |
| 275/55R18 | 29.91 in | 760 mm | +3.0% |
| 235/55R18 | 28.18 in | 716 mm | -3.0% |
Plus and minus sizes
Changing the rim size? These options on 17-, 19- and 20-inch rims keep the overall diameter within ±3%.
| Size | Diameter | mm | Difference |
|---|---|---|---|
| 255/60R17 | 29.05 in | 738 mm | +0.0% |
| 255/50R19 | 29.04 in | 738 mm | -0.0% |
| 255/45R20 | 29.04 in | 738 mm | -0.0% |
| 285/45R19 | 29.10 in | 739 mm | +0.2% |
| 285/40R20 | 28.98 in | 736 mm | -0.2% |
| 275/55R17 | 28.91 in | 734 mm | -0.5% |
| 285/55R17 | 29.34 in | 745 mm | +1.0% |
| 275/45R19 | 28.74 in | 730 mm | -1.0% |
| 265/45R20 | 29.39 in | 746 mm | +1.2% |
| 245/45R20 | 28.68 in | 728 mm | -1.2% |
Compare 255/55R18 with another size →
Frequently asked questions
How tall is a 255/55R18 tire?
About 29.04 inches (738 mm) in overall diameter.
How wide is a 255/55R18 tire?
The section width is 255 mm, about 10.0 inches.
What size can replace 255/55R18?
On the same rim, 235/60R18 is the closest size (+0.2% diameter). Use only sizes approved for your vehicle.
How many revolutions per mile does a 255/55R18 tire make?
About 694 revolutions per mile (431 per km).
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