255/65R18 tire size
A 255/65R18 tire is 31.05 inches (788.7 mm) tall, 10.04 in (255 mm) wide and fits a 18-inch wheel. In inch notation it is roughly a 31.1x10.0R18 — a "31-inch" tire.
| Overall diameter | 31.05 in | 788.7 mm |
|---|---|---|
| Section width | 10.04 in | 255 mm |
| Sidewall height | 6.53 in | 165.8 mm |
| Circumference | 97.55 in | 2,478 mm |
| Revolutions | 649.5 per mile | 403.6 per km |
| Rim diameter | 18 in | 457.2 mm |
Compare 255/65R18 with another size
Alternative sizes on the same 18-inch wheel
Sizes in use within ±3 % of the overall diameter of 255/65R18:
Plus and minus sizes for 255/65R18
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 275/70R16 | Minus 2 (16 in) | 31.16 in | +0.34% |
| 235/80R16 | Minus 2 (16 in) | 30.80 in | −0.80% |
| 265/70R16 | Minus 2 (16 in) | 30.61 in | −1.43% |
| 245/75R16 | Minus 2 (16 in) | 30.47 in | −1.88% |
| 255/70R17 | Minus 1 (17 in) | 31.06 in | +0.01% |
| 275/65R17 | Minus 1 (17 in) | 31.07 in | +0.08% |
| 245/75R17 | Minus 1 (17 in) | 31.47 in | +1.34% |
| 265/65R17 | Minus 1 (17 in) | 30.56 in | −1.57% |
| 255/60R19 | Plus 1 (19 in) | 31.05 in | −0.01% |
| 235/65R19 | Plus 1 (19 in) | 31.03 in | −0.08% |
| 275/55R19 | Plus 1 (19 in) | 30.91 in | −0.46% |
| 265/55R19 | Plus 1 (19 in) | 30.48 in | −1.85% |
| 255/55R20 | Plus 2 (20 in) | 31.04 in | −0.03% |
| 235/60R20 | Plus 2 (20 in) | 31.10 in | +0.16% |
| 285/50R20 | Plus 2 (20 in) | 31.22 in | +0.55% |
| 275/50R20 | Plus 2 (20 in) | 30.83 in | −0.72% |
| 255/50R21 | Plus 3 (21 in) | 31.04 in | −0.04% |
| 285/45R21 | Plus 3 (21 in) | 31.10 in | +0.15% |
| 275/45R21 | Plus 3 (21 in) | 30.74 in | −0.99% |
| 305/40R21 | Plus 3 (21 in) | 30.61 in | −1.43% |
Vehicles approved with 255/65R18 tires
Models whose Swiss type approval lists 255/65R18 as a standard or optional size (9 approvals in total). Always check your own vehicle's placard or papers.
Source: Swiss Federal Roads Office (FEDRO/ASTRA), open government data. Original data (downloaded 2026-09-29). Data processed by us; errors in processing are ours, not the publisher's.
Nearby 18-inch sizes
Reading the 255/65R18 size
- 255 — section width in millimetres (10.04 in).
- 65 — aspect ratio: the sidewall is 65 % of the width, 165.8 mm.
- R — radial construction (ZR on the sidewall means a high-speed rated radial; the dimensions are the same).
- 18 — fits a 18-inch diameter wheel.
The load index and speed rating (for example 91V) follow the size on the sidewall. They must meet at least the values on your vehicle's tire placard.