30.1" tall, 10.0" wide, 6.5" sidewall
A 255/65R17 tire is 30.1 inches (763 mm) tall and 10.0 inches wide. The sidewall is 65% of the width, 6.5 inches, on a 17-inch wheel, and the tire turns about 671 times per mile.
In flotation terms that is about 30.1x10.0R17. People often call it a 30-inch tire.
The size most often compared with it is 245/70R17, which is 0.5" taller (+1.5%). At an indicated 60 mph you would be doing 60.9 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 255/65R17 | |
|---|---|---|---|---|---|
| 275/60R17 | 30.0" | 10.8" | 6.5" | −0.2% | |
| 235/70R17 | 30.0" | 9.3" | 6.5" | −0.3% | |
| 245/70R17 | 30.5" | 9.6" | 6.8" | +1.5% | compare |
| 265/65R17 | 30.6" | 10.4" | 6.8" | +1.7% | compare |
| 265/60R17 | 29.5" | 10.4" | 6.3" | −1.8% | |
| 255/70R17 | 31.1" | 10.0" | 7.0" | +3.3% | |
| 275/65R17 | 31.1" | 10.8" | 7.0" | +3.4% | |
| 275/55R17 | 28.9" | 10.8" | 6.0" | −3.8% | |
| 245/75R17 | 31.5" | 9.6" | 7.2" | +4.7% | |
| 245/60R17 | 28.6" | 9.6" | 5.8" | −4.9% |
Sizes within 2% of 30.1" on 16" or 15" wheels.
| Size | Diameter | Width | Sidewall | vs 255/65R17 | |
|---|---|---|---|---|---|
| 255/70R16 | 30.1" | 10.0" | 7.0" | +0.0% | |
| 255/75R15 | 30.1" | 10.0" | 7.5" | +0.0% | |
| 275/65R16 | 30.1" | 10.8" | 7.0" | +0.1% | |
| 295/65R15 | 30.1" | 11.6" | 7.5" | +0.2% | |
| 30x9.50R15 | 30.0" | 9.5" | 7.5" | −0.2% | |
| 275/70R15 | 30.2" | 10.8" | 7.6" | +0.4% |
Actual speed when the speedometer is calibrated for 255/65R17.
| Speedometer shows | on 245/70R17 | on 265/70R17 | on 265/65R17 |
|---|---|---|---|
| 30 mph | 30.5 mph | 31.6 mph | 30.5 mph |
| 45 mph | 45.7 mph | 47.3 mph | 45.8 mph |
| 60 mph | 60.9 mph | 63.1 mph | 61.0 mph |
| 70 mph | 71.1 mph | 73.6 mph | 71.2 mph |
30.1 inches (763 mm). The sidewall is 6.5 inches.
10.0 inches (255 mm) section width, measured sidewall to sidewall.
About 30.1x10.0R17.
245/70R17 is +1.5% in diameter, within the common 3% guideline. It is 0.4" narrower.