27.0" tall, 10.0" wide, 3.5" sidewall
A 255/35R20 tire is 27.0 inches (687 mm) tall and 10.0 inches wide. The sidewall is 35% of the width, 3.5 inches, on a 20-inch wheel, and the tire turns about 746 times per mile.
In flotation terms that is about 27.0x10.0R20. People often call it a 27-inch tire.
The size most often compared with it is 275/35R20, which is 0.6" taller (+2.0%). At an indicated 60 mph you would be doing 61.2 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 255/35R20 | |
|---|---|---|---|---|---|
| 265/35R20 | 27.3" | 10.4" | 3.7" | +1.0% | |
| 275/35R20 | 27.6" | 10.8" | 3.8" | +2.0% | compare |
Sizes within 2% of 27.0" on 18" or 19" wheels.
| Size | Diameter | Width | Sidewall | vs 255/35R20 | |
|---|---|---|---|---|---|
| 255/45R18 | 27.0" | 10.0" | 4.5" | +0.0% | |
| 285/40R18 | 27.0" | 11.2" | 4.5" | −0.2% | |
| 285/35R19 | 26.9" | 11.2" | 3.9" | −0.6% | |
| 295/40R18 | 27.3" | 11.6" | 4.6" | +1.0% | |
| 275/40R18 | 26.7" | 10.8" | 4.3" | −1.4% |
Actual speed when the speedometer is calibrated for 255/35R20.
| Speedometer shows | on 275/35R20 | on 265/35R20 |
|---|---|---|
| 30 mph | 30.6 mph | 30.3 mph |
| 45 mph | 45.9 mph | 45.5 mph |
| 60 mph | 61.2 mph | 60.6 mph |
| 70 mph | 71.4 mph | 70.7 mph |
27.0 inches (687 mm). The sidewall is 3.5 inches.
10.0 inches (255 mm) section width, measured sidewall to sidewall.
About 27.0x10.0R20.
275/35R20 is +2.0% in diameter, within the common 3% guideline. It is 0.8" wider.