38.0" tall, 13.5" wide on a 20" wheel
A 38x13.50R20 tire is 38.0 inches tall and 13.5 inches wide and mounts on a 20-inch wheel, which leaves a 9.0-inch sidewall. It turns about 531 times per mile.
The size most often compared with it is 37x13.50R20, which is 1.0" shorter (−2.6%). At an indicated 60 mph you would be doing 58.4 mph on it.
| Current | New | Difference |
|---|
| Shows | Actual speed |
|---|
Same 20" wheel, within 20 mm of width and 10 points of aspect ratio.
| Size | Diameter | Width | Sidewall | vs 38x13.50R20 | |
|---|---|---|---|---|---|
| 37x13.50R20 | 37.0" | 13.5" | 8.5" | −2.6% | |
| 325/60R20 | 35.4" | 12.8" | 7.7" | −7.0% |
Actual speed when the speedometer is calibrated for 38x13.50R20.
| Speedometer shows | on 37x13.50R20 | on 325/60R20 |
|---|---|---|
| 30 mph | 29.2 mph | 27.9 mph |
| 45 mph | 43.8 mph | 41.9 mph |
| 60 mph | 58.4 mph | 55.8 mph |
| 70 mph | 68.2 mph | 65.1 mph |
38.0 inches (965 mm), with a 9.0-inch sidewall on a 20-inch wheel.
There is no common metric size within half an inch of 38.0".
About 531, or 330 per kilometer.