315/70R17 tire size in inches and millimeters
315/70R17 measures 34.36 inches in overall diameter, 12.40 inches in section width, with a 8.68 inch sidewall.
Every dimension
| Size | In inches | In millimetres |
|---|---|---|
| Overall diameter | 34.36 in | 872.8 mm |
| Section width | 12.40 in | 315 mm |
| Sidewall height | 8.68 in | 220.5 mm |
| Circumference | 107.95 in | 2,742.0 mm |
| Revolutions per mile | 586.9 per mile | 364.7 per km |
Sizes that fit the same wheel
These sizes share a 17 inch wheel diameter and sit within 3% of 315/70R17 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) |
|---|---|---|---|---|
| 275/80R17 | 34.32 | -0.04 | -0.11 | -1.57 |
| 295/75R17 | 34.42 | 0.06 | 0.17 | -0.79 |
| 335/65R17 | 34.15 | -0.22 | -0.63 | 0.79 |
| 255/85R17 | 34.07 | -0.30 | -0.86 | -2.36 |
| 345/65R17 | 34.66 | 0.30 | 0.86 | 1.18 |
| 265/85R17 | 34.74 | 0.37 | 1.09 | -1.97 |
| 285/75R17 | 33.83 | -0.53 | -1.55 | -1.18 |
| 305/70R17 | 33.81 | -0.55 | -1.60 | -0.39 |
| 325/70R17 | 34.91 | 0.55 | 1.60 | 0.39 |
| 285/80R17 | 34.95 | 0.59 | 1.72 | -1.18 |
| 355/60R17 | 33.77 | -0.59 | -1.72 | 1.57 |
| 305/75R17 | 35.01 | 0.65 | 1.89 | -0.39 |
| 265/80R17 | 33.69 | -0.67 | -1.95 | -1.97 |
| 325/65R17 | 33.63 | -0.73 | -2.12 | 0.39 |
| 355/65R17 | 35.17 | 0.81 | 2.35 | 1.57 |
| 245/85R17 | 33.40 | -0.96 | -2.81 | -2.76 |
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 315/70R17: the sidewall is 220.5 millimetres, two of them are 17.36 inches, and adding the 17 inch wheel gives 34.36 inches overall.
Questions
What size is 315/70R17 in inches?
34.36 inches in overall diameter, 12.40 inches in section width, with a 8.68 inch sidewall.
How tall is a 315/70R17 tire?
34.36 inches, which is 872.8 millimetres.
What do the numbers in 315/70R17 mean?
315 is the section width in millimetres, 70 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: 34.36 inches.
Does 315/70R17 fit a 17-inch wheel?
Yes — the 17 in a metric tire size *is* the wheel diameter, so 315/70R17 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 315/70R17?
275/80R17, 295/75R17, 335/65R17 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.