38x11.50R20 tire size
38x11.50R20 is a flotation (inch) size: 38.0" tall, 11.5" wide, on a 20" rim — about a 290/80R20. The sidewall is 9.0" and the tire turns 531 times per mile.
38x11.50R20 specs
| Overall diameter (height) | 38.00" · 965 mm |
|---|---|
| Section width | 11.50" · 292 mm |
| Sidewall height | 9.00" · 229 mm (78% of width) |
| Rim diameter | 20" |
| Circumference | 119.38" · 3.032 m |
| Revolutions per mile | 531 (330 per km) |
| Closest metric size | 290/80R20 |
Equivalent sizes on a 20" rim
Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 37x12.50R20 | 37.00" | -2.63% | +26 mm | 58.4 mph | calculate → |
| 37x13.50R20 | 37.00" | -2.63% | +51 mm | 58.4 mph | calculate → |
| 38x13.50R20 | 38.00" | 0.00% | +51 mm | 60.0 mph | calculate → |
| 38x15.50R20 | 38.00" | 0.00% | +102 mm | 60.0 mph | calculate → |
| 37x11.50R20 | 37.00" | -2.63% | 0 mm | 58.4 mph | calculate → |
| 38x14.50R20 | 38.00" | 0.00% | +76 mm | 60.0 mph | calculate → |
| 39.5x13.50R20 | 39.50" | +3.95% | +51 mm | 62.4 mph | calculate → |
| 38.5x13.50R20 | 38.50" | +1.32% | +51 mm | 60.8 mph | calculate → |
| 38.5x14.50R20 | 38.50" | +1.32% | +76 mm | 60.8 mph | calculate → |
| 395/60R20 | 38.66" | +1.74% | +103 mm | 61.0 mph | calculate → |
| 37x14.50R20 | 37.00" | -2.63% | +76 mm | 58.4 mph | calculate → |
| 375/55R20 | 36.24" | -4.63% | +83 mm | 57.2 mph | calculate → |
| 39x13.50R20 | 39.00" | +2.63% | +51 mm | 61.6 mph | calculate → |
| 355/60R20 | 36.77" | -3.23% | +63 mm | 58.1 mph | calculate → |
| 39.5x15.00R20 | 39.50" | +3.95% | +89 mm | 62.4 mph | calculate → |
| 345/60R20 | 36.30" | -4.48% | +53 mm | 57.3 mph | calculate → |
Try another size against 38x11.50R20
Questions
What size is 38x11.50R20 in inches?
38x11.50R20 is about 38.0" tall and 11.5" wide on a 20-inch rim — roughly a 290/80R20 in inch sizing.
What does 38x11.50R20 mean?
38" overall diameter, 11.50" section width, radial, 20" rim.
What tire sizes are equivalent to 38x11.50R20?
On the same 20" rim, within 3% of the diameter: 38x13.50R20 (0.00%), 38x14.50R20 (0.00%), 38x15.50R20 (0.00%), 38.5x13.50R20 (+1.32%), 38.5x14.50R20 (+1.32%), 395/60R20 (+1.74%).
How many revolutions per mile does a 38x11.50R20 tire make?
About 531 revolutions per mile (circumference 119.4").
How these numbers are computed
Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.