26.0" tall, 10.0" wide, 4.5" sidewall
A 255/45R17 tire is 26.0 inches (661 mm) tall and 10.0 inches wide. The sidewall is 45% of the width, 4.5 inches, on a 17-inch wheel, and the tire turns about 775 times per mile.
In flotation terms that is about 26.0x10.0R17. People often call it a 26-inch tire.
The size most often compared with it is 275/40R17, which is 0.4" shorter (−1.4%). At an indicated 60 mph you would be doing 59.1 mph on it.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 17" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 255/45R17 | |
|---|---|---|---|---|---|
| 275/40R17 | 25.7" | 10.8" | 4.3" | −1.4% | |
| 255/40R17 | 25.0" | 10.0" | 4.0" | −3.9% | |
| 245/40R17 | 24.7" | 9.6" | 3.9" | −5.1% | |
| 265/50R17 | 27.4" | 10.4" | 5.2" | +5.4% | |
| 275/35R17 | 24.6" | 10.8" | 3.8" | −5.6% | |
| 245/55R17 | 27.6" | 9.6" | 5.3" | +6.0% | |
| 235/40R17 | 24.4" | 9.3" | 3.7" | −6.3% | |
| 275/50R17 | 27.8" | 10.8" | 5.4" | +6.9% | |
| 275/55R17 | 28.9" | 10.8" | 6.0" | +11.0% |
Sizes within 2% of 26.0" on 18" or 15" or 19" wheels.
| Size | Diameter | Width | Sidewall | vs 255/45R17 | |
|---|---|---|---|---|---|
| 255/40R18 | 26.0" | 10.0" | 4.0" | −0.0% | |
| 255/55R15 | 26.0" | 10.0" | 5.5" | +0.0% | |
| 215/65R15 | 26.0" | 8.5" | 5.5" | −0.1% | |
| 235/60R15 | 26.1" | 9.3" | 5.6" | +0.3% | |
| 295/35R18 | 26.1" | 11.6" | 4.1" | +0.4% | |
| 305/30R19 | 26.2" | 12.0" | 3.6" | +0.7% |
Actual speed when the speedometer is calibrated for 255/45R17.
| Speedometer shows | on 275/40R17 | on 255/40R17 | on 245/40R17 |
|---|---|---|---|
| 30 mph | 29.6 mph | 28.8 mph | 28.5 mph |
| 45 mph | 44.4 mph | 43.3 mph | 42.7 mph |
| 60 mph | 59.1 mph | 57.7 mph | 57.0 mph |
| 70 mph | 69.0 mph | 67.3 mph | 66.5 mph |
26.0 inches (661 mm). The sidewall is 4.5 inches.
10.0 inches (255 mm) section width, measured sidewall to sidewall.
About 26.0x10.0R17.
275/40R17 is −1.4% in diameter, within the common 3% guideline. It is 0.8" wider.