42.5x13.50R20 tire size
42.5x13.50R20 is a flotation (inch) size: 42.5" tall, 13.5" wide, on a 20" rim — about a 340/85R20. The sidewall is 11.3" and the tire turns 475 times per mile.
42.5x13.50R20 specs
| Overall diameter (height) | 42.50" · 1080 mm |
|---|---|
| Section width | 13.50" · 343 mm |
| Sidewall height | 11.25" · 286 mm (83% of width) |
| Rim diameter | 20" |
| Circumference | 133.52" · 3.391 m |
| Revolutions per mile | 475 (295 per km) |
| Closest metric size | 340/85R20 |
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 | |
|---|---|---|---|---|---|
| 42x14.50R20 | 42.00" | -1.18% | +25 mm | 59.3 mph | calculate → |
| 42x13.50R20 | 42.00" | -1.18% | 0 mm | 59.3 mph | calculate → |
| 42x15.00R20 | 42.00" | -1.18% | +38 mm | 59.3 mph | calculate → |
| 43x14.50R20 | 43.00" | +1.18% | +25 mm | 60.7 mph | calculate → |
| 43x15.00R20 | 43.00" | +1.18% | +38 mm | 60.7 mph | calculate → |
| 41x14.50R20 | 41.00" | -3.53% | +25 mm | 57.9 mph | calculate → |
| 44x13.50R20 | 44.00" | +3.53% | 0 mm | 62.1 mph | calculate → |
| 44x19.50R20 | 44.00" | +3.53% | +152 mm | 62.1 mph | calculate → |
| 44x21.00R20 | 44.00" | +3.53% | +190 mm | 62.1 mph | calculate → |
Try another size against 42.5x13.50R20
Questions
What size is 42.5x13.50R20 in inches?
42.5x13.50R20 is about 42.5" tall and 13.5" wide on a 20-inch rim — roughly a 340/85R20 in inch sizing.
What does 42.5x13.50R20 mean?
42.5" overall diameter, 13.50" section width, radial, 20" rim.
What tire sizes are equivalent to 42.5x13.50R20?
On the same 20" rim, within 3% of the diameter: 42x13.50R20 (-1.18%), 42x14.50R20 (-1.18%), 42x15.00R20 (-1.18%), 43x14.50R20 (+1.18%), 43x15.00R20 (+1.18%), 41x14.50R20 (-3.53%).
How many revolutions per mile does a 42.5x13.50R20 tire make?
About 475 revolutions per mile (circumference 133.5").
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.