255/75R17 tire size in inches and millimeters
255/75R17 measures 32.06 inches in overall diameter, 10.04 inches in section width, with a 7.53 inch sidewall.
Every dimension
| Size | In inches | In millimetres |
|---|---|---|
| Overall diameter | 32.06 in | 814.3 mm |
| Section width | 10.04 in | 255 mm |
| Sidewall height | 7.53 in | 191.2 mm |
| Circumference | 100.72 in | 2,558.2 mm |
| Revolutions per mile | 629.1 per mile | 390.9 per km |
Sizes that fit the same wheel
These sizes share a 17 inch wheel diameter and sit within 3% of 255/75R17 in overall diameter, which is the range a swap stays inside without recalibrating anything.
The percentage difference in overall diameter is the speedometer error: a tire 2% taller makes an indicated 60 mph a true 61.2 mph. They are the same number, so it is shown once.
| Alternate size | Overall diameter | Difference (in) | Difference (%) | Width difference (in) |
|---|---|---|---|---|
| 225/85R17 | 32.06 | 0.00 | 0.00 | -1.18 |
| 295/65R17 | 32.10 | 0.04 | 0.12 | 1.57 |
| 275/70R17 | 32.16 | 0.10 | 0.31 | 0.79 |
| 345/55R17 | 31.94 | -0.12 | -0.37 | 3.54 |
| 315/60R17 | 31.88 | -0.18 | -0.55 | 2.36 |
| 235/80R17 | 31.80 | -0.26 | -0.80 | -0.79 |
| 325/60R17 | 32.35 | 0.30 | 0.92 | 2.76 |
| 355/55R17 | 32.37 | 0.32 | 0.98 | 3.94 |
| 245/80R17 | 32.43 | 0.37 | 1.17 | -0.39 |
| 265/70R17 | 31.61 | -0.45 | -1.41 | 0.39 |
| 285/65R17 | 31.59 | -0.47 | -1.47 | 1.18 |
| 305/65R17 | 32.61 | 0.55 | 1.72 | 1.97 |
| 335/55R17 | 31.51 | -0.55 | -1.72 | 3.15 |
| 245/75R17 | 31.47 | -0.59 | -1.84 | -0.39 |
| 265/75R17 | 32.65 | 0.59 | 1.84 | 0.39 |
| 285/70R17 | 32.71 | 0.65 | 2.03 | 1.18 |
| 305/60R17 | 31.41 | -0.65 | -2.03 | 1.97 |
| 215/85R17 | 31.39 | -0.67 | -2.09 | -1.57 |
| 235/85R17 | 32.73 | 0.67 | 2.09 | -0.79 |
| 335/60R17 | 32.83 | 0.77 | 2.39 | 3.15 |
| 225/80R17 | 31.17 | -0.89 | -2.76 | -1.18 |
How this is worked out
sidewall height in millimetres = section width × aspect ratio ÷ 100
overall diameter in inches = wheel diameter + (section width × aspect ratio × 2) ÷ 2540
section width in inches = section width in millimetres ÷ 25.4
circumference in inches = π × overall diameter
revolutions per mile = 63360 ÷ circumference in inches
The divisor is 2540, not the 2550 some converters publish. Two sidewalls in inches are 2 × width × aspect ÷ (100 × 25.4), and the rounding costs about 0.07 inches at 34 inches.
For 255/75R17: the sidewall is 191.2 millimetres, two of them are 15.06 inches, and adding the 17 inch wheel gives 32.06 inches overall.
Questions
What size is 255/75R17 in inches?
32.06 inches in overall diameter, 10.04 inches in section width, with a 7.53 inch sidewall.
How tall is a 255/75R17 tire?
32.06 inches, which is 814.3 millimetres.
What do the numbers in 255/75R17 mean?
255 is the section width in millimetres, 75 is the sidewall height as a percentage of that width, and 17 is the wheel diameter in inches. Overall diameter is the wheel diameter plus two sidewalls: 32.06 inches.
Does 255/75R17 fit a 17-inch wheel?
Yes — the 17 in a metric tire size *is* the wheel diameter, so 255/75R17 is made for a 17 inch wheel. Rim width is a separate question the sidewall code does not answer.
What tire sizes are equivalent to 255/75R17?
225/85R17, 295/65R17, 275/70R17 are the closest by overall diameter, all on the same 17 inch wheel.
Fitting a size is not only a matter of diameter. Rim width, load rating, speed rating and clearance all decide whether a size works on a given vehicle, and none of them can be read off the sidewall code alone.