275/60R20 vs 33x12.50R20 tire size
A 33x12.50R20 is the same height as a 275/60R20, and 1.67 inches (42 mm) wider. Fit them in place of 275/60R20 tires and the speedometer reads the same.
Sources checked
| Dimension | 275/60R20 | 33x12.50R20 | Change |
|---|---|---|---|
| Overall diameter | 32.99 in (838 mm) | 33.00 in (838 mm) | +0.01 in (0 mm) |
| Section width | 10.83 in (275 mm) | 12.50 in (318 mm) | +1.67 in (+43 mm) |
| Sidewall height | 6.50 in (165 mm) | 6.50 in (165 mm) | 0.00 in (0 mm) |
| Aspect ratio | 60% | 52% | |
| Rim diameter | 20 in | 20 in | |
| Circumference | 103.6 in (2,633 mm) | 103.7 in (2,633 mm) | +0.1 in |
| Revolutions per mile | 611 | 611 | 0 |
| Revolutions per km | 380 | 380 | 0 |
Check another speed or size
Metric, LT and flotation
At 60 mph on the speedometer you’re doing
60.0mph
No change: the two sizes are the same height.
- Height
- +0.01 in (0 mm)
- Width
- +1.67 in (+42 mm)
- Ground clearance
- 0.00 in (0 mm)
- Each side, same wheel
- +0.84 in (+21 mm)
275/60R20 and 33x12.50R20LT side by side
| Dimension | 275/60R20 | 33x12.50R20LT | Change |
|---|---|---|---|
| Overall diameter | 32.99 in (838 mm) | 33.00 in (838 mm) | +0.01 in (0 mm) |
| Section width | 10.83 in (275 mm) | 12.50 in (318 mm) | +1.67 in (+43 mm) |
| Sidewall height | 6.50 in (165 mm) | 6.50 in (165 mm) | 0.00 in (0 mm) |
| Aspect ratio | 60% | 52% | |
| Rim diameter | 20 in | 20 in | |
| Circumference | 103.6 in | 103.7 in | +0.1 in |
| Revolutions per mile | 611 | 611 | 0 |
| Revolutions per km | 380 | 380 | 0 |
The working
- 275/60R20: sidewall = 275 mm × 60% = 165.0 mm = 6.50 in.
- Diameter = rim + 2 × sidewall = 20 + 2 × 6.50 = 32.99 in (838 mm).
- Circumference = π × 32.99 = 103.6 in; revolutions per mile = 63,360 ÷ 103.6 = 611.
- 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.
- Speedometer. True speed = what it shows × new diameter ÷ old = 60 × 33.00 ÷ 32.99 = 60.0 mph.
- Ground clearance. Half the change in diameter: (33.00 − 32.99) ÷ 2 = 0.00 in.
Speedometer
The 275/60R20 and 33x12.50R20 are within 0.05% of the same height, so the speedometer reads the same.
Clearance
- Ground clearance: no change.
- Top of the tread: no change.
- Each side, on the same wheel: +0.84 in (+21 mm), toward the suspension inside and toward the fender lip outside.
A new wheel with a different width or offset moves the tire again. The sidewall goes from 6.50 to 6.50 inches.
What tire makers publish
Inflated on the maker’s measuring rim; the percentage is against the arithmetic.
| Tire | Size as printed | Diameter | Width | Revs per mile |
|---|---|---|---|---|
| Toyo Open Country A/T III | 275/60R20 | 33 in (0.0%) | 11 in | 630 |
| Toyo Open Country A/T III | LT275/60R20 | 33 in (0.0%) | 11 in | 630 |
| 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 | – |
Each size on its own
- 275/60R20 tire size: 33.0 × 10.8 in
- 33x12.50R20 tire size: 33.0 × 12.5 in
Other comparisons
Questions
Can I fit 33x12.50R20 tires instead of 275/60R20?
They fit the same 20-inch wheels. A 33x12.50R20 is the same height as a 275/60R20, and 1.67 inches (42 mm) wider, so check three things first: that your wheels are within the 33x12.50R20’s approved rim width range, which tire makers list for each size; that it clears the fenders and suspension at full lock and full travel; and that its load index meets what your door-jamb placard asks for.
How far off is the speedometer with 33x12.50R20 tires?
Not measurably: the two sizes are within 0.05% of the same height.
Does 33x12.50R20 change the ground clearance?
No: the two sizes are the same height. On the same wheel, each sidewall sits 0.84 inches further out, inside and outside.
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.