255/45R20 Tire Size
Dimensions of a 255/45R20 tire in inches and millimeters, with equivalent and plus sizes.
255/45R20 dimensions
A 255/45R20 tire is 255 mm wide with a sidewall that is 45% of the width (115 mm), mounted on a 20-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 | 4.52 in | 114.8 mm |
| Rim diameter | 20 in | 508 mm |
| Circumference | 91.2 in | 2317 mm |
| Revolutions | 695 per mile | 432 per km |
Equivalent sizes on a 20-inch rim
These sizes stay within ±3% of the 255/45R20 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 |
|---|---|---|---|
| 235/50R20 | 29.25 in | 743 mm | +0.7% |
| 245/45R20 | 28.68 in | 728 mm | -1.2% |
| 265/45R20 | 29.39 in | 746 mm | +1.2% |
| 275/40R20 | 28.66 in | 728 mm | -1.3% |
| 245/50R20 | 29.65 in | 753 mm | +2.1% |
| 265/40R20 | 28.35 in | 720 mm | -2.4% |
| 235/45R20 | 28.33 in | 720 mm | -2.4% |
| 275/45R20 | 29.74 in | 756 mm | +2.4% |
Plus and minus sizes
Changing the rim size? These options on 19-, 21- and 22-inch rims keep the overall diameter within ±3%.
| Size | Diameter | mm | Difference |
|---|---|---|---|
| 255/50R19 | 29.04 in | 738 mm | +0.0% |
| 255/40R21 | 29.03 in | 737 mm | -0.0% |
| 255/35R22 | 29.03 in | 737 mm | -0.0% |
| 285/45R19 | 29.10 in | 739 mm | +0.2% |
| 285/35R21 | 28.85 in | 733 mm | -0.6% |
| 265/35R22 | 29.30 in | 744 mm | +0.9% |
| 245/35R22 | 28.75 in | 730 mm | -1.0% |
| 275/45R19 | 28.74 in | 730 mm | -1.0% |
| 285/30R22 | 28.73 in | 730 mm | -1.0% |
| 265/40R21 | 29.35 in | 745 mm | +1.1% |
Compare 255/45R20 with another size →
Frequently asked questions
How tall is a 255/45R20 tire?
About 29.04 inches (738 mm) in overall diameter.
How wide is a 255/45R20 tire?
The section width is 255 mm, about 10.0 inches.
What size can replace 255/45R20?
On the same rim, 235/50R20 is the closest size (+0.7% diameter). Use only sizes approved for your vehicle.
How many revolutions per mile does a 255/45R20 tire make?
About 695 revolutions per mile (432 per km).
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