24.7" tall, 9.6" wide, 3.9" sidewall
A 245/40R17 tire is 24.7 inches (628 mm) tall and 9.6 inches wide. The sidewall is 40% of the width, 3.9 inches, on a 17-inch wheel, and the tire turns about 816 times per mile.
In flotation terms that is about 24.7x9.6R17. People often call it a 25-inch tire.
The size most often compared with it is 235/40R17, which is 0.3" shorter (−1.3%). At an indicated 60 mph you would be doing 59.2 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 245/40R17 | |
|---|---|---|---|---|---|
| 235/40R17 | 24.4" | 9.3" | 3.7" | −1.3% | compare |
| 255/40R17 | 25.0" | 10.0" | 4.0" | +1.3% | |
| 255/45R17 | 26.0" | 10.0" | 4.5" | +5.3% | |
| 265/50R17 | 27.4" | 10.4" | 5.2" | +11.0% |
Sizes within 2% of 24.7" on 18" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 245/40R17 | |
|---|---|---|---|---|---|
| 285/30R18 | 24.7" | 11.2" | 3.4" | +0.1% | |
| 225/50R16 | 24.9" | 8.9" | 4.4" | +0.6% | |
| 275/30R18 | 24.5" | 10.8" | 3.2" | −0.9% | |
| 215/50R16 | 24.5" | 8.5" | 4.2" | −1.0% | |
| 295/30R18 | 25.0" | 11.6" | 3.5" | +1.0% | |
| 255/35R18 | 25.0" | 10.0" | 3.5" | +1.3% |
Actual speed when the speedometer is calibrated for 245/40R17.
| Speedometer shows | on 235/40R17 | on 255/40R17 | on 255/45R17 |
|---|---|---|---|
| 30 mph | 29.6 mph | 30.4 mph | 31.6 mph |
| 45 mph | 44.4 mph | 45.6 mph | 47.4 mph |
| 60 mph | 59.2 mph | 60.8 mph | 63.2 mph |
| 70 mph | 69.1 mph | 70.9 mph | 73.7 mph |
24.7 inches (628 mm). The sidewall is 3.9 inches.
9.6 inches (245 mm) section width, measured sidewall to sidewall.
About 24.7x9.6R17.
235/40R17 is −1.3% in diameter, within the common 3% guideline. It is 0.4" narrower.