28.9" tall, 9.3" wide, 6.9" sidewall
A 235/75R15 tire is 28.9 inches (734 mm) tall and 9.3 inches wide. The sidewall is 75% of the width, 6.9 inches, on a 15-inch wheel, and the tire turns about 698 times per mile.
In flotation terms that is about 28.9x9.3R15. People often call it a 29-inch tire.
The size most often compared with it is 255/75R15, which is 1.2" taller (+4.1%). At an indicated 60 mph you would be doing 62.5 mph on it, more than the 3% change many shops use as a limit.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 15" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 235/75R15 | |
|---|---|---|---|---|---|
| 255/70R15 | 29.1" | 10.0" | 7.0" | +0.6% | compare |
| 215/80R15 | 28.5" | 8.5" | 6.8" | −1.2% | |
| 245/70R15 | 28.5" | 9.6" | 6.8" | −1.3% | |
| 245/75R15 | 29.5" | 9.6" | 7.2" | +2.0% | |
| 255/65R15 | 28.1" | 10.0" | 6.5" | −2.9% | |
| 235/70R15 | 28.0" | 9.3" | 6.5" | −3.2% | compare |
| 30x9.50R15 | 30.0" | 9.5" | 7.5" | +3.9% | compare |
| 255/75R15 | 30.1" | 10.0" | 7.5" | +4.1% | compare |
| 215/75R15 | 27.7" | 8.5" | 6.3" | −4.1% | |
| 225/70R15 | 27.4" | 8.9" | 6.2" | −5.1% |
Sizes within 2% of 28.9" on 17" or 16" wheels.
| Size | Diameter | Width | Sidewall | vs 235/75R15 | |
|---|---|---|---|---|---|
| 275/55R17 | 28.9" | 10.8" | 6.0" | +0.1% | |
| 205/80R16 | 28.9" | 8.1" | 6.5" | +0.1% | |
| 275/60R16 | 29.0" | 10.8" | 6.5" | +0.4% | |
| 245/60R17 | 28.6" | 9.6" | 5.8" | −1.0% | |
| 245/65R16 | 28.5" | 9.6" | 6.3" | −1.2% | |
| 325/45R17 | 28.5" | 12.8" | 5.8" | −1.3% |
Actual speed when the speedometer is calibrated for 235/75R15.
| Speedometer shows | on 255/75R15 | on 235/70R15 | on 255/70R15 |
|---|---|---|---|
| 30 mph | 31.2 mph | 29.0 mph | 30.2 mph |
| 45 mph | 46.8 mph | 43.6 mph | 45.3 mph |
| 60 mph | 62.5 mph | 58.1 mph | 60.4 mph |
| 70 mph | 72.9 mph | 67.8 mph | 70.4 mph |
28.9 inches (734 mm). The sidewall is 6.9 inches.
9.3 inches (235 mm) section width, measured sidewall to sidewall.
About 28.9x9.3R15.
255/75R15 is +4.1% in diameter, more than the common 3% guideline, so expect a speedometer error and check clearance. It is 0.8" wider.