31.9" tall, 10.8" wide, 6.0" sidewall
A 275/55R20 tire is 31.9 inches (811 mm) tall and 10.8 inches wide. The sidewall is 55% of the width, 6.0 inches, on a 20-inch wheel, and the tire turns about 632 times per mile.
In flotation terms that is about 31.9x10.8R20. People often call it a 32-inch tire.
The size most often compared with it is 275/60R20, which is 1.1" taller (+3.4%). At an indicated 60 mph you would be doing 62.0 mph on it, more than the 3% change many shops use as a limit.
| 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 275/55R20 | |
|---|---|---|---|---|---|
| 255/60R20 | 32.0" | 10.0" | 6.0" | +0.4% | |
| 295/50R20 | 31.6" | 11.6" | 5.8" | −0.9% | |
| 265/55R20 | 31.5" | 10.4" | 5.7" | −1.4% | |
| 285/55R20 | 32.3" | 11.2" | 6.2" | +1.4% | compare |
| 265/60R20 | 32.5" | 10.4" | 6.3" | +1.9% | compare |
| 285/50R20 | 31.2" | 11.2" | 5.6" | −2.2% | compare |
| 295/55R20 | 32.8" | 11.6" | 6.4" | +2.7% | |
| 275/50R20 | 30.8" | 10.8" | 5.4" | −3.4% | |
| 275/60R20 | 33.0" | 10.8" | 6.5" | +3.4% | compare |
| 255/65R20 | 33.1" | 10.0" | 6.5" | +3.6% |
Sizes within 2% of 31.9" on 22" or 18" wheels.
| Size | Diameter | Width | Sidewall | vs 275/55R20 | |
|---|---|---|---|---|---|
| 315/40R22 | 31.9" | 12.4" | 5.0" | +0.0% | |
| 295/60R18 | 31.9" | 11.6" | 7.0" | +0.1% | |
| 235/75R18 | 31.9" | 9.3" | 6.9" | −0.1% | |
| 255/70R18 | 32.1" | 10.0" | 7.0" | +0.5% | |
| 275/45R22 | 31.7" | 10.8" | 4.9" | −0.5% | |
| 275/65R18 | 32.1" | 10.8" | 7.0" | +0.5% |
Actual speed when the speedometer is calibrated for 275/55R20.
| Speedometer shows | on 275/60R20 | on 245/60R20 | on 265/60R20 |
|---|---|---|---|
| 30 mph | 31.0 mph | 29.7 mph | 30.6 mph |
| 45 mph | 46.5 mph | 44.5 mph | 45.9 mph |
| 60 mph | 62.0 mph | 59.4 mph | 61.1 mph |
| 70 mph | 72.4 mph | 69.3 mph | 71.3 mph |
31.9 inches (811 mm). The sidewall is 6.0 inches.
10.8 inches (275 mm) section width, measured sidewall to sidewall.
About 31.9x10.8R20.
275/60R20 is +3.4% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.0" wider.