28.5" tall, 12.8" wide, 5.8" sidewall
A 325/45R17 tire is 28.5 inches (724 mm) tall and 12.8 inches wide. The sidewall is 45% of the width, 5.8 inches, on a 17-inch wheel, and the tire turns about 707 times per mile.
In flotation terms that is about 28.5x12.8R17. People often call it a 29-inch tire.
The size most often compared with it is 315/50R17, which is 0.9" taller (+3.1%). At an indicated 60 mph you would be doing 61.9 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 325/45R17 | |
|---|---|---|---|---|---|
| 315/50R17 | 29.4" | 12.4" | 6.2" | +3.1% | |
| 305/55R17 | 30.2" | 12.0" | 6.6" | +5.9% | |
| 305/40R17 | 26.6" | 12.0" | 4.8" | −6.7% | |
| 315/55R17 | 30.6" | 12.4" | 6.8" | +7.5% | |
| 315/35R17 | 25.7" | 12.4" | 4.3" | −9.9% |
Sizes within 2% of 28.5" on 15" or 16" or 18" wheels.
| Size | Diameter | Width | Sidewall | vs 325/45R17 | |
|---|---|---|---|---|---|
| 245/70R15 | 28.5" | 9.6" | 6.8" | −0.0% | |
| 245/65R16 | 28.5" | 9.6" | 6.3" | +0.1% | |
| 215/80R15 | 28.5" | 8.5" | 6.8" | +0.1% | |
| 265/65R15 | 28.6" | 10.4" | 6.8" | +0.2% | |
| 285/60R15 | 28.5" | 11.2" | 6.7" | −0.2% | |
| 295/45R18 | 28.5" | 11.6" | 5.2" | −0.2% |
Actual speed when the speedometer is calibrated for 325/45R17.
| Speedometer shows | on 315/50R17 | on 305/55R17 | on 305/40R17 |
|---|---|---|---|
| 30 mph | 30.9 mph | 31.8 mph | 28.0 mph |
| 45 mph | 46.4 mph | 47.7 mph | 42.0 mph |
| 60 mph | 61.9 mph | 63.6 mph | 56.0 mph |
| 70 mph | 72.2 mph | 74.2 mph | 65.3 mph |
28.5 inches (724 mm). The sidewall is 5.8 inches.
12.8 inches (325 mm) section width, measured sidewall to sidewall.
About 28.5x12.8R17.
315/50R17 is +3.1% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.4" narrower.