35.7" tall, 11.2" wide, 7.9" sidewall
A 285/70R20 tire is 35.7 inches (907 mm) tall and 11.2 inches wide. The sidewall is 70% of the width, 7.9 inches, on a 20-inch wheel, and the tire turns about 565 times per mile.
In flotation terms that is about 35.7x11.2R20. People often call it a 36-inch tire.
The size most often compared with it is 265/75R20, 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 20" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 285/70R20 | |
|---|---|---|---|---|---|
| 265/75R20 | 35.6" | 10.4" | 7.8" | −0.2% | |
| 305/65R20 | 35.6" | 12.0" | 7.8" | −0.3% | |
| 275/75R20 | 36.2" | 10.8" | 8.1" | +1.5% | |
| 275/70R20 | 35.2" | 10.8" | 7.6" | −1.5% | |
| 295/70R20 | 36.3" | 11.6" | 8.1" | +1.5% | |
| 295/65R20 | 35.1" | 11.6" | 7.5" | −1.7% | |
| 35x11.50R20 | 35.0" | 11.5" | 7.5" | −2.0% | |
| 265/70R20 | 34.6" | 10.4" | 7.3" | −3.1% | |
| 285/65R20 | 34.6" | 11.2" | 7.3" | −3.1% | |
| 37x11.50R20 | 37.0" | 11.5" | 8.5" | +3.6% |
Sizes within 2% of 35.7" on 19" or 22" or 18" wheels.
| Size | Diameter | Width | Sidewall | vs 285/70R20 | |
|---|---|---|---|---|---|
| 305/70R19 | 35.8" | 12.0" | 8.4" | +0.3% | |
| 245/70R22 | 35.5" | 9.6" | 6.8" | −0.6% | |
| 325/70R18 | 35.9" | 12.8" | 9.0" | +0.6% | |
| 295/60R22 | 35.9" | 11.6" | 7.0" | +0.6% | |
| 285/60R22 | 35.5" | 11.2" | 6.7" | −0.7% | |
| 285/80R18 | 36.0" | 11.2" | 9.0" | +0.7% |
Actual speed when the speedometer is calibrated for 285/70R20.
| Speedometer shows | on 265/75R20 | on 305/65R20 | on 275/75R20 |
|---|---|---|---|
| 30 mph | 30.0 mph | 29.9 mph | 30.4 mph |
| 45 mph | 44.9 mph | 44.9 mph | 45.7 mph |
| 60 mph | 59.9 mph | 59.8 mph | 60.9 mph |
| 70 mph | 69.9 mph | 69.8 mph | 71.0 mph |
35.7 inches (907 mm). The sidewall is 7.9 inches.
11.2 inches (285 mm) section width, measured sidewall to sidewall.
About 35.7x11.2R20.
265/75R20 is −0.2% in diameter, within the common 3% guideline. It is 0.8" narrower.