32.3" tall, 11.2" wide, 6.2" sidewall
A 285/55R20 tire is 32.3 inches (822 mm) tall and 11.2 inches wide. The sidewall is 55% of the width, 6.2 inches, on a 20-inch wheel, and the tire turns about 624 times per mile.
In flotation terms that is about 32.3x11.2R20. People often call it a 32-inch tire.
The size most often compared with it is 275/55R20, which is 0.4" shorter (−1.3%). At an indicated 60 mph you would be doing 59.2 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 285/55R20 | |
|---|---|---|---|---|---|
| 265/60R20 | 32.5" | 10.4" | 6.3" | +0.5% | |
| 305/50R20 | 32.0" | 12.0" | 6.0" | −1.0% | |
| 275/55R20 | 31.9" | 10.8" | 6.0" | −1.3% | compare |
| 295/55R20 | 32.8" | 11.6" | 6.4" | +1.3% | |
| 275/60R20 | 33.0" | 10.8" | 6.5" | +2.0% | compare |
| 295/50R20 | 31.6" | 11.6" | 5.8" | −2.3% | |
| 265/55R20 | 31.5" | 10.4" | 5.7" | −2.7% | |
| 305/55R20 | 33.2" | 12.0" | 6.6" | +2.7% | |
| 285/60R20 | 33.5" | 11.2" | 6.7" | +3.5% | |
| 285/50R20 | 31.2" | 11.2" | 5.6" | −3.5% |
Sizes within 2% of 32.3" on 19" or 18" or 22" wheels.
| Size | Diameter | Width | Sidewall | vs 285/55R20 | |
|---|---|---|---|---|---|
| 225/75R19 | 32.3" | 8.9" | 6.6" | −0.2% | |
| 305/60R18 | 32.4" | 12.0" | 7.2" | +0.2% | |
| 265/50R22 | 32.4" | 10.4" | 5.2" | +0.3% | |
| 325/40R22 | 32.2" | 12.8" | 5.1" | −0.3% | |
| 295/45R22 | 32.5" | 11.6" | 5.2" | +0.3% | |
| 245/75R18 | 32.5" | 9.6" | 7.2" | +0.4% |
Actual speed when the speedometer is calibrated for 285/55R20.
| Speedometer shows | on 275/55R20 | on 275/60R20 | on 33x12.50R20 |
|---|---|---|---|
| 30 mph | 29.6 mph | 30.6 mph | 30.6 mph |
| 45 mph | 44.4 mph | 45.9 mph | 45.9 mph |
| 60 mph | 59.2 mph | 61.2 mph | 61.2 mph |
| 70 mph | 69.1 mph | 71.4 mph | 71.4 mph |
32.3 inches (822 mm). The sidewall is 6.2 inches.
11.2 inches (285 mm) section width, measured sidewall to sidewall.
About 32.3x11.2R20.
275/55R20 is −1.3% in diameter, within the common 3% guideline. It is 0.4" narrower.