32.6" tall, 11.2" wide, 7.3" sidewall
A 285/65R18 tire is 32.6 inches (828 mm) tall and 11.2 inches wide. The sidewall is 65% of the width, 7.3 inches, on a 18-inch wheel, and the tire turns about 619 times per mile.
In flotation terms that is about 32.6x11.2R18, closest to the common 33x12.50R18 (33.0"). People often call it a 33-inch tire.
The size most often compared with it is 265/65R18, which is 1.0" shorter (−3.1%). At an indicated 60 mph you would be doing 58.1 mph on it, more than the 3% change many shops use as a limit.
| 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 285/65R18 | |
|---|---|---|---|---|---|
| 265/70R18 | 32.6" | 10.4" | 7.3" | +0.1% | |
| 305/60R18 | 32.4" | 12.0" | 7.2" | −0.5% | |
| 275/65R18 | 32.1" | 10.8" | 7.0" | −1.6% | compare |
| 295/65R18 | 33.1" | 11.6" | 7.5" | +1.6% | |
| 275/70R18 | 33.2" | 10.8" | 7.6" | +1.8% | compare |
| 295/60R18 | 31.9" | 11.6" | 7.0" | −2.0% | |
| 265/65R18 | 31.6" | 10.4" | 6.8" | −3.1% | compare |
| 305/65R18 | 33.6" | 12.0" | 7.8" | +3.1% | |
| 265/75R18 | 33.6" | 10.4" | 7.8" | +3.3% | |
| 285/60R18 | 31.5" | 11.2" | 6.7" | −3.4% | compare |
Sizes within 2% of 32.6" on 17" or 20" or 19" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 285/65R18 | |
|---|---|---|---|---|---|
| 305/65R17 | 32.6" | 12.0" | 7.8" | +0.1% | |
| 265/75R17 | 32.6" | 10.4" | 7.8" | +0.2% | |
| 265/60R20 | 32.5" | 10.4" | 6.3" | −0.2% | |
| 245/70R19 | 32.5" | 9.6" | 6.8" | −0.3% | |
| 265/80R16 | 32.7" | 10.4" | 8.3" | +0.3% | |
| 285/70R17 | 32.7" | 11.2" | 7.9" | +0.4% |
Actual speed when the speedometer is calibrated for 285/65R18.
| Speedometer shows | on 265/65R18 | on 275/70R18 | on 285/60R18 |
|---|---|---|---|
| 30 mph | 29.1 mph | 30.5 mph | 29.0 mph |
| 45 mph | 43.6 mph | 45.8 mph | 43.5 mph |
| 60 mph | 58.1 mph | 61.1 mph | 57.9 mph |
| 70 mph | 67.8 mph | 71.2 mph | 67.6 mph |
32.6 inches (828 mm). The sidewall is 7.3 inches.
11.2 inches (285 mm) section width, measured sidewall to sidewall.
About 32.6x11.2R18; the closest common flotation size is 33x12.50R18 at 33.0".
265/65R18 is −3.1% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.8" narrower.