33.2" tall, 10.8" wide, 7.6" sidewall
A 275/70R18 tire is 33.2 inches (842 mm) tall and 10.8 inches wide. The sidewall is 70% of the width, 7.6 inches, on a 18-inch wheel, and the tire turns about 608 times per mile.
In flotation terms that is about 33.2x10.8R18, closest to the common 33x12.50R18 (33.0"). People often call it a 33-inch tire.
The size most often compared with it is 275/65R18, which is 1.1" shorter (−3.3%). At an indicated 60 mph you would be doing 58.0 mph on it, more than the 3% change many shops use as a limit.
| Current | New | Difference |
|---|
| Shows | Actual speed |
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Same 18" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 275/70R18 | |
|---|---|---|---|---|---|
| 295/65R18 | 33.1" | 11.6" | 7.5" | −0.2% | |
| 255/75R18 | 33.1" | 10.0" | 7.5" | −0.3% | |
| 265/75R18 | 33.6" | 10.4" | 7.8" | +1.5% | compare |
| 265/70R18 | 32.6" | 10.4" | 7.3" | −1.7% | compare |
| 285/70R18 | 33.7" | 11.2" | 7.9" | +1.7% | compare |
| 285/65R18 | 32.6" | 11.2" | 7.3" | −1.7% | compare |
| 255/80R18 | 34.1" | 10.0" | 8.0" | +2.7% | |
| 275/65R18 | 32.1" | 10.8" | 7.0" | −3.3% | compare |
| 275/75R18 | 34.2" | 10.8" | 8.1" | +3.3% | |
| 255/70R18 | 32.1" | 10.0" | 7.0" | −3.3% |
Sizes within 2% of 33.2" on 17" or 20" or 16" or 19" wheels.
| Size | Diameter | Width | Sidewall | vs 275/70R18 | |
|---|---|---|---|---|---|
| 315/65R17 | 33.1" | 12.4" | 8.1" | −0.1% | |
| 305/55R20 | 33.2" | 12.0" | 6.6" | +0.2% | |
| 255/85R16 | 33.1" | 10.0" | 8.5" | −0.3% | |
| 255/80R17 | 33.1" | 10.0" | 8.0" | −0.3% | |
| 295/70R17 | 33.3" | 11.6" | 8.1" | +0.3% | compare |
| 255/70R19 | 33.1" | 10.0" | 7.0" | −0.3% |
Actual speed when the speedometer is calibrated for 275/70R18.
| Speedometer shows | on 275/65R18 | on 285/70R18 | on 325/65R18 |
|---|---|---|---|
| 30 mph | 29.0 mph | 30.5 mph | 31.3 mph |
| 45 mph | 43.5 mph | 45.7 mph | 47.0 mph |
| 60 mph | 58.0 mph | 61.0 mph | 62.7 mph |
| 70 mph | 67.7 mph | 71.2 mph | 73.1 mph |
33.2 inches (842 mm). The sidewall is 7.6 inches.
10.8 inches (275 mm) section width, measured sidewall to sidewall.
About 33.2x10.8R18; the closest common flotation size is 33x12.50R18 at 33.0".
275/65R18 is −3.3% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.0" wider.