30.7" tall, 11.2" wide, 7.9" sidewall
A 285/70R15 tire is 30.7 inches (780 mm) tall and 11.2 inches wide. The sidewall is 70% of the width, 7.9 inches, on a 15-inch wheel, and the tire turns about 657 times per mile.
In flotation terms that is about 30.7x11.2R15, closest to the common 31x10.50R15 (31.0"). People often call it a 31-inch tire.
The size most often compared with it is 265/75R15, which is 0.1" shorter (−0.2%). At an indicated 60 mph you would be doing 59.9 mph on it.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 15" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 285/70R15 | |
|---|---|---|---|---|---|
| 265/75R15 | 30.6" | 10.4" | 7.8" | −0.2% | |
| 31x10.50R15 | 31.0" | 10.5" | 8.0" | +0.9% | |
| 275/75R15 | 31.2" | 10.8" | 8.1" | +1.7% | |
| 295/70R15 | 31.3" | 11.6" | 8.1" | +1.8% | |
| 275/70R15 | 30.2" | 10.8" | 7.6" | −1.8% | |
| 295/65R15 | 30.1" | 11.6" | 7.5" | −2.0% | |
| 265/70R15 | 29.6" | 10.4" | 7.3" | −3.6% | |
| 305/70R15 | 31.8" | 12.0" | 8.4" | +3.6% | |
| 285/75R15 | 31.8" | 11.2" | 8.4" | +3.7% | |
| 32x11.50R15 | 32.0" | 11.5" | 8.5" | +4.2% |
Sizes within 2% of 30.7" on 17" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 285/70R15 | |
|---|---|---|---|---|---|
| 315/55R17 | 30.6" | 12.4" | 6.8" | −0.2% | |
| 265/70R16 | 30.6" | 10.4" | 7.3" | −0.3% | |
| 285/65R16 | 30.6" | 11.2" | 7.3" | −0.4% | |
| 265/65R17 | 30.6" | 10.4" | 6.8" | −0.5% | |
| 245/70R17 | 30.5" | 9.6" | 6.8" | −0.7% | |
| 245/75R16 | 30.5" | 9.6" | 7.2" | −0.8% |
Actual speed when the speedometer is calibrated for 285/70R15.
| Speedometer shows | on 265/75R15 | on 31x10.50R15 | on 275/75R15 |
|---|---|---|---|
| 30 mph | 29.9 mph | 30.3 mph | 30.5 mph |
| 45 mph | 44.9 mph | 45.4 mph | 45.8 mph |
| 60 mph | 59.9 mph | 60.6 mph | 61.0 mph |
| 70 mph | 69.9 mph | 70.7 mph | 71.2 mph |
30.7 inches (780 mm). The sidewall is 7.9 inches.
11.2 inches (285 mm) section width, measured sidewall to sidewall.
About 30.7x11.2R15; the closest common flotation size is 31x10.50R15 at 31.0".
265/75R15 is −0.2% in diameter, within the common 3% guideline. It is 0.8" narrower.