40x14.50R20 tire size
40x14.50R20 is a flotation (inch) size: 40.0" tall, 14.5" wide, on a 20" rim — about a 370/70R20. The sidewall is 10.0" and the tire turns 504 times per mile.
40x14.50R20 specs
| Overall diameter (height) | 40.00" · 1016 mm |
|---|---|
| Section width | 14.50" · 368 mm |
| Sidewall height | 10.00" · 254 mm (69% of width) |
| Rim diameter | 20" |
| Circumference | 125.66" · 3.192 m |
| Revolutions per mile | 504 (313 per km) |
| Closest metric size | 370/70R20 |
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 | |
|---|---|---|---|---|---|
| 38x13.50R20 | 38.00" | -5.00% | -25 mm | 57.0 mph | calculate → |
| 38x15.50R20 | 38.00" | -5.00% | +26 mm | 57.0 mph | calculate → |
| 40x15.50R20 | 40.00" | 0.00% | +26 mm | 60.0 mph | calculate → |
| 42x14.50R20 | 42.00" | +5.00% | 0 mm | 63.0 mph | calculate → |
| 40x13.50R20 | 40.00" | 0.00% | -25 mm | 60.0 mph | calculate → |
| 39.5x13.50R20 | 39.50" | -1.25% | -25 mm | 59.3 mph | calculate → |
| 38x14.50R20 | 38.00" | -5.00% | 0 mm | 57.0 mph | calculate → |
| 42x13.50R20 | 42.00" | +5.00% | -25 mm | 63.0 mph | calculate → |
| 41x14.50R20 | 41.00" | +2.50% | 0 mm | 61.5 mph | calculate → |
| 395/60R20 | 38.66" | -3.35% | +27 mm | 58.0 mph | calculate → |
| 38.5x13.50R20 | 38.50" | -3.75% | -25 mm | 57.8 mph | calculate → |
| 38.5x14.50R20 | 38.50" | -3.75% | 0 mm | 57.8 mph | calculate → |
| 38x11.50R20 | 38.00" | -5.00% | -76 mm | 57.0 mph | calculate → |
| 42x15.00R20 | 42.00" | +5.00% | +13 mm | 63.0 mph | calculate → |
| 39.5x15.00R20 | 39.50" | -1.25% | +13 mm | 59.3 mph | calculate → |
| 39x13.50R20 | 39.00" | -2.50% | -25 mm | 58.5 mph | calculate → |
Try another size against 40x14.50R20
Questions
What size is 40x14.50R20 in inches?
40x14.50R20 is about 40.0" tall and 14.5" wide on a 20-inch rim — roughly a 370/70R20 in inch sizing.
What does 40x14.50R20 mean?
40" overall diameter, 14.50" section width, radial, 20" rim.
What tire sizes are equivalent to 40x14.50R20?
On the same 20" rim, within 3% of the diameter: 40x13.50R20 (0.00%), 40x15.50R20 (0.00%), 39.5x13.50R20 (-1.25%), 39.5x15.00R20 (-1.25%), 39x13.50R20 (-2.50%), 41x14.50R20 (+2.50%).
How many revolutions per mile does a 40x14.50R20 tire make?
About 504 revolutions per mile (circumference 125.7").
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.