34.7" tall, 10.4" wide, 8.3" sidewall
A 265/80R18 tire is 34.7 inches (881 mm) tall and 10.4 inches wide. The sidewall is 80% of the width, 8.3 inches, on a 18-inch wheel, and the tire turns about 581 times per mile.
In flotation terms that is about 34.7x10.4R18, closest to the common 35x12.50R18 (35.0"). People often call it a 35-inch tire.
The size most often compared with it is 285/75R18, which is 0.1" taller (+0.4%). At an indicated 60 mph you would be doing 60.2 mph on it.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 18" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 265/80R18 | |
|---|---|---|---|---|---|
| 285/75R18 | 34.8" | 11.2" | 8.4" | +0.4% | |
| 275/75R18 | 34.2" | 10.8" | 8.1" | −1.3% | |
| 255/80R18 | 34.1" | 10.0" | 8.0" | −1.8% | |
| 275/80R18 | 35.3" | 10.8" | 8.7" | +1.8% | |
| 285/70R18 | 33.7" | 11.2" | 7.9" | −2.8% | |
| 265/75R18 | 33.6" | 10.4" | 7.8" | −3.0% | |
| 285/80R18 | 36.0" | 11.2" | 9.0" | +3.6% | |
| 275/70R18 | 33.2" | 10.8" | 7.6" | −4.4% | |
| 255/75R18 | 33.1" | 10.0" | 7.5" | −4.7% | |
| 275/85R18 | 36.4" | 10.8" | 9.2" | +4.9% |
Sizes within 2% of 34.7" on 17" or 20" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 265/80R18 | |
|---|---|---|---|---|---|
| 265/85R17 | 34.7" | 10.4" | 8.9" | +0.1% | |
| 265/70R20 | 34.6" | 10.4" | 7.3" | −0.2% | |
| 315/75R16 | 34.6" | 12.4" | 9.3" | −0.3% | |
| 285/65R20 | 34.6" | 11.2" | 7.3" | −0.3% | |
| 315/60R20 | 34.9" | 12.4" | 7.4" | +0.5% | |
| 325/70R17 | 34.9" | 12.8" | 9.0" | +0.6% |
Actual speed when the speedometer is calibrated for 265/80R18.
| Speedometer shows | on 285/75R18 | on 275/75R18 | on 255/80R18 |
|---|---|---|---|
| 30 mph | 30.1 mph | 29.6 mph | 29.5 mph |
| 45 mph | 45.2 mph | 44.4 mph | 44.2 mph |
| 60 mph | 60.2 mph | 59.2 mph | 58.9 mph |
| 70 mph | 70.3 mph | 69.1 mph | 68.7 mph |
34.7 inches (881 mm). The sidewall is 8.3 inches.
10.4 inches (265 mm) section width, measured sidewall to sidewall.
About 34.7x10.4R18; the closest common flotation size is 35x12.50R18 at 35.0".
285/75R18 is +0.4% in diameter, within the common 3% guideline. It is 0.8" wider.