30.5" tall, 9.6" wide, 6.8" sidewall
A 245/70R17 tire is 30.5 inches (775 mm) tall and 9.6 inches wide. The sidewall is 70% of the width, 6.8 inches, on a 17-inch wheel, and the tire turns about 661 times per mile.
In flotation terms that is about 30.5x9.6R17. People often call it a 31-inch tire.
The size most often compared with it is 235/80R17, which is 1.3" taller (+4.3%). At an indicated 60 mph you would be doing 62.6 mph on it, more than the 3% change many shops use as a limit.
| 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 245/70R17 | |
|---|---|---|---|---|---|
| 265/65R17 | 30.6" | 10.4" | 6.8" | +0.2% | |
| 225/75R17 | 30.3" | 8.9" | 6.6" | −0.7% | |
| 255/65R17 | 30.1" | 10.0" | 6.5" | −1.5% | compare |
| 255/70R17 | 31.1" | 10.0" | 7.0" | +1.8% | |
| 235/70R17 | 30.0" | 9.3" | 6.5" | −1.8% | |
| 225/80R17 | 31.2" | 8.9" | 7.1" | +2.2% | |
| 245/75R17 | 31.5" | 9.6" | 7.2" | +3.2% | |
| 265/60R17 | 29.5" | 10.4" | 6.3" | −3.2% | |
| 225/70R17 | 29.4" | 8.9" | 6.2" | −3.6% | |
| 265/70R17 | 31.6" | 10.4" | 7.3" | +3.6% | compare |
Sizes within 2% of 30.5" on 16" or 18" or 15" wheels.
| Size | Diameter | Width | Sidewall | vs 245/70R17 | |
|---|---|---|---|---|---|
| 245/75R16 | 30.5" | 9.6" | 7.2" | −0.1% | |
| 245/65R18 | 30.5" | 9.6" | 6.3" | +0.1% | |
| 285/65R16 | 30.6" | 11.2" | 7.3" | +0.3% | |
| 265/70R16 | 30.6" | 10.4" | 7.3" | +0.3% | |
| 215/85R16 | 30.4" | 8.5" | 7.2" | −0.4% | |
| 265/75R15 | 30.6" | 10.4" | 7.8" | +0.5% |
Actual speed when the speedometer is calibrated for 245/70R17.
| Speedometer shows | on 235/80R17 | on 265/70R17 | on 255/65R17 |
|---|---|---|---|
| 30 mph | 31.3 mph | 31.1 mph | 29.6 mph |
| 45 mph | 46.9 mph | 46.6 mph | 44.3 mph |
| 60 mph | 62.6 mph | 62.2 mph | 59.1 mph |
| 70 mph | 73.0 mph | 72.5 mph | 69.0 mph |
30.5 inches (775 mm). The sidewall is 6.8 inches.
9.6 inches (245 mm) section width, measured sidewall to sidewall.
About 30.5x9.6R17.
235/80R17 is +4.3% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.4" narrower.