35.3" tall, 10.8" wide, 8.7" sidewall
A 275/80R18 tire is 35.3 inches (897 mm) tall and 10.8 inches wide. The sidewall is 80% of the width, 8.7 inches, on a 18-inch wheel, and the tire turns about 571 times per mile.
In flotation terms that is about 35.3x10.8R18, closest to the common 35x12.50R18 (35.0"). People often call it a 35-inch tire.
The size most often compared with it is 295/75R18, which is 0.1" taller (+0.3%). 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 275/80R18 | |
|---|---|---|---|---|---|
| 295/75R18 | 35.4" | 11.6" | 8.7" | +0.3% | |
| 285/75R18 | 34.8" | 11.2" | 8.4" | −1.4% | |
| 265/80R18 | 34.7" | 10.4" | 8.3" | −1.8% | |
| 285/80R18 | 36.0" | 11.2" | 9.0" | +1.8% | |
| 295/70R18 | 34.3" | 11.6" | 8.1" | −3.0% | |
| 275/75R18 | 34.2" | 10.8" | 8.1" | −3.1% | |
| 275/85R18 | 36.4" | 10.8" | 9.2" | +3.1% | |
| 255/80R18 | 34.1" | 10.0" | 8.0" | −3.6% | |
| 285/70R18 | 33.7" | 11.2" | 7.9" | −4.6% | |
| 265/75R18 | 33.6" | 10.4" | 7.8" | −4.7% |
Sizes within 2% of 35.3" on 20" or 17" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 275/80R18 | |
|---|---|---|---|---|---|
| 325/60R20 | 35.4" | 12.8" | 7.7" | +0.1% | |
| 275/85R17 | 35.4" | 10.8" | 9.2" | +0.2% | |
| 325/75R16 | 35.2" | 12.8" | 9.6" | −0.4% | |
| 275/70R20 | 35.2" | 10.8" | 7.6" | −0.5% | |
| 295/65R20 | 35.1" | 11.6" | 7.5" | −0.6% | |
| 285/85R16 | 35.1" | 11.2" | 9.5" | −0.7% |
Actual speed when the speedometer is calibrated for 275/80R18.
| Speedometer shows | on 295/75R18 | on 285/75R18 | on 265/80R18 |
|---|---|---|---|
| 30 mph | 30.1 mph | 29.6 mph | 29.5 mph |
| 45 mph | 45.1 mph | 44.4 mph | 44.2 mph |
| 60 mph | 60.2 mph | 59.2 mph | 58.9 mph |
| 70 mph | 70.2 mph | 69.0 mph | 68.8 mph |
35.3 inches (897 mm). The sidewall is 8.7 inches.
10.8 inches (275 mm) section width, measured sidewall to sidewall.
About 35.3x10.8R18; the closest common flotation size is 35x12.50R18 at 35.0".
295/75R18 is +0.3% in diameter, within the common 3% guideline. It is 0.8" wider.