33x12.50R20 tire size
A 33x12.50R20 tire is 33 inches (838 mm) tall and 12.5 inches (318 mm) wide by its name, for a 20-inch wheel, so each sidewall is 6.5 inches (165 mm). It makes about 611 revolutions a mile.
Sources checked
| Dimension | 33x12.50R20 |
|---|---|
| Overall diameter | 33.00 in (838 mm) |
| Section width | 12.50 in (318 mm) |
| Sidewall height | 6.50 in (165 mm) |
| Aspect ratio | 52% |
| Rim diameter | 20 in |
| Circumference | 103.7 in (2,633 mm) |
| Revolutions per mile | 611 |
| Revolutions per km | 380 |
Compare 33x12.50R20 with another size
Metric, LT and flotation
At 60 mph on the speedometer you’re doing
63.6mph
+6.1% · the speedometer reads low
- Height
- +2.00 in (+51 mm)
- Width
- 0.00 in (0 mm)
- Ground clearance
- +1.00 in (+25 mm)
- Each side, same wheel
- 0.00 in (0 mm)
33x12.50R20LT and 35x12.50R20LT side by side
| Dimension | 33x12.50R20LT | 35x12.50R20LT | Change |
|---|---|---|---|
| Overall diameter | 33.00 in (838 mm) | 35.00 in (889 mm) | +2.00 in (+51 mm) |
| Section width | 12.50 in (318 mm) | 12.50 in (318 mm) | 0.00 in (0 mm) |
| Sidewall height | 6.50 in (165 mm) | 7.50 in (191 mm) | +1.00 in (+26 mm) |
| Aspect ratio | 52% | 60% | |
| Rim diameter | 20 in | 20 in | |
| Circumference | 103.7 in | 110.0 in | +6.3 in |
| Revolutions per mile | 611 | 576 | −35 |
| Revolutions per km | 380 | 358 | −22 |
The working
- 33x12.50R20LT: 33.00 in tall and 12.50 in wide, as the size says.
- Sidewall = (diameter − rim) ÷ 2 = (33 − 20) ÷ 2 = 6.50 in.
- Circumference = π × 33.00 = 103.7 in; revolutions per mile = 63,360 ÷ 103.7 = 611.
- 35x12.50R20LT: 35.00 in tall and 12.50 in wide, as the size says.
- Sidewall = (diameter − rim) ÷ 2 = (35 − 20) ÷ 2 = 7.50 in.
- Circumference = π × 35.00 = 110.0 in; revolutions per mile = 63,360 ÷ 110.0 = 576.
- Speedometer. True speed = what it shows × new diameter ÷ old = 60 × 35.00 ÷ 33.00 = 63.6 mph.
- Ground clearance. Half the change in diameter: (35.00 − 33.00) ÷ 2 = +1.00 in.
Where the 33x12.50R20 numbers come from
A flotation size names its height and width: 33 inches tall and 12.5 inches wide, on a 20-inch rim. Each sidewall is what’s left: (33 − 20) ÷ 2 = 6.50 inches, so the sidewall is 52% of the width.
One turn covers π × 33.00 = 103.7 inches, so the tire turns 611 times a mile and 380 times a kilometer.
What tire makers publish for 33x12.50R20
Inflated on the maker’s measuring rim. The percentage is the printed diameter against the 33.00 inches worked out above.
| Tire | Size as printed | Diameter | Width | Revs per mile |
|---|---|---|---|---|
| Toyo Open Country A/T III | 33X12.50R20LT | 32.5 in (−1.5%) | 12.5 in | 639 |
| Nitto Trail Grappler M/T | 33x12.50R20LT | 32.76 in (−0.7%) | 12.52 in | – |
Other 20-inch sizes against 33x12.50R20
Each size’s height against 33x12.50R20, and what a speedometer set for 33x12.50R20 shows at 60 mph with that size on.
| Size | Diameter | Width | Height change | At 60 mph shown |
|---|---|---|---|---|
| 245/50R20 | 29.6 in | 9.6 in | −10.2% | 53.9 mph |
| 255/50R20 | 30.0 in | 10.0 in | −9.0% | 54.6 mph |
| 255/55R20 | 31.0 in | 10.0 in | −5.9% | 56.4 mph |
| 275/55R20 | 31.9 in | 10.8 in | −3.3% | 58.0 mph |
| 275/60R20 compared | 33.0 in | 10.8 in | 0.0% | 60.0 mph |
| 275/65R20 | 34.1 in | 10.8 in | +3.3% | 62.0 mph |
| 285/55R20 | 32.3 in | 11.2 in | −2.0% | 58.8 mph |
| 285/60R20 | 33.5 in | 11.2 in | +1.4% | 60.8 mph |
| 35x12.50R20 compared | 35.0 in | 12.5 in | +6.1% | 63.6 mph |
33x12.50R20 compared
Every size: the tire size calculator. With the wheels off, the nuts go back on at your vehicle’s lug nut torque.
Questions
How tall is a 33x12.50R20 tire really?
33 inches by its name. Measured inflated, the makers’ tables on this page give 32.5 to 32.76 inches. Tread depth and the rim it’s measured on make the difference.
How many revolutions per mile does a 33x12.50R20 make?
611 by its diameter: 63,360 inches in a mile ÷ 103.7 inches a turn. Tire makers’ published figures are measured under load, when the tire rolls on a slightly smaller radius, and run 2.8% to 3.3% higher in Toyo’s tables.
What metric size is closest to 33x12.50R20?
Of the common 20-inch sizes, 275/60R20: the same height and 1.67 inches (42 mm) narrower.
Is 33x12.50R20 an LT tire?
Yes. Bridgestone’s guide describes flotation sizes as light-truck tires, written with LT after the rim: 33x12.50R20LT. They carry one load index, as they’re not made to run as duals.
Sources
- Bridgestone Americas: Determining tire size: P-metric, Euro-metric, LT-metric, C-type and flotation sizes, and what each number means (checked October 28, 2026)
- Toyo Tires: Extensa A/S II sizes and specifications: inflated overall diameter and width, revolutions per mile (checked October 28, 2026)
- Toyo Tires: Proxes Sport A/S sizes and specifications: inflated overall diameter and width, revolutions per mile (checked October 28, 2026)
- Toyo Tires: Open Country A/T III sizes and specifications: P-metric, LT-metric and flotation sizes, with revolutions per mile (checked October 28, 2026)
- Nitto Tire: Trail Grappler M/T sizes and specs: inflated overall diameter and width, LT-metric and flotation sizes (checked October 28, 2026)
Spotted a number that doesn’t match your manual or a source? Tell us; corrections are logged on the sources page.