275/65R20 vs 35x12.50R20 tire size
A 35x12.50R20 is 0.93 inches (24 mm) taller and 1.67 inches (42 mm) wider than a 275/65R20. Fit them in place of 275/65R20 tires and the speedometer reads low: at 60 mph on it you’re doing 61.6 mph, 2.7% faster, and the vehicle sits 0.46 inches (12 mm) higher.
Sources checked
| Dimension | 275/65R20 | 35x12.50R20 | Change |
|---|---|---|---|
| Overall diameter | 34.07 in (865 mm) | 35.00 in (889 mm) | +0.93 in (+24 mm) |
| Section width | 10.83 in (275 mm) | 12.50 in (318 mm) | +1.67 in (+43 mm) |
| Sidewall height | 7.04 in (179 mm) | 7.50 in (191 mm) | +0.46 in (+12 mm) |
| Aspect ratio | 65% | 60% | |
| Rim diameter | 20 in | 20 in | |
| Circumference | 107.0 in (2,719 mm) | 110.0 in (2,793 mm) | +3.0 in |
| Revolutions per mile | 592 | 576 | −16 |
| Revolutions per km | 368 | 358 | −10 |
Check another speed or size
Metric, LT and flotation
At 60 mph on the speedometer you’re doing
61.6mph
+2.7% · the speedometer reads low
- Height
- +0.93 in (+24 mm)
- Width
- +1.67 in (+42 mm)
- Ground clearance
- +0.46 in (+12 mm)
- Each side, same wheel
- +0.84 in (+21 mm)
275/65R20 and 35x12.50R20LT side by side
| Dimension | 275/65R20 | 35x12.50R20LT | Change |
|---|---|---|---|
| Overall diameter | 34.07 in (865 mm) | 35.00 in (889 mm) | +0.93 in (+24 mm) |
| Section width | 10.83 in (275 mm) | 12.50 in (318 mm) | +1.67 in (+43 mm) |
| Sidewall height | 7.04 in (179 mm) | 7.50 in (191 mm) | +0.46 in (+12 mm) |
| Aspect ratio | 65% | 60% | |
| Rim diameter | 20 in | 20 in | |
| Circumference | 107.0 in | 110.0 in | +3.0 in |
| Revolutions per mile | 592 | 576 | −16 |
| Revolutions per km | 368 | 358 | −10 |
The working
- 275/65R20: sidewall = 275 mm × 65% = 178.8 mm = 7.04 in.
- Diameter = rim + 2 × sidewall = 20 + 2 × 7.04 = 34.07 in (865 mm).
- Circumference = π × 34.07 = 107.0 in; revolutions per mile = 63,360 ÷ 107.0 = 592.
- 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 ÷ 34.07 = 61.6 mph.
- Ground clearance. Half the change in diameter: (35.00 − 34.07) ÷ 2 = +0.46 in.
Speedometer
A 35x12.50R20 turns 576 times a mile against the 275/65R20’s 592. With a speedometer set for 275/65R20, true speed is what it shows × 35.00 ÷ 34.07:
| Speedometer shows | True speed | Difference |
|---|---|---|
| 25 mph | 25.7 mph | +0.7 mph |
| 35 mph | 36.0 mph | +1.0 mph |
| 45 mph | 46.2 mph | +1.2 mph |
| 55 mph | 56.5 mph | +1.5 mph |
| 65 mph | 66.8 mph | +1.8 mph |
| 75 mph | 77.0 mph | +2.0 mph |
Clearance
- Ground clearance: +0.46 in (+12 mm), half the change in diameter.
- Top of the tread: +0.46 in (+12 mm), so that much less room under the fender.
- 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 7.04 to 7.50 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 | LT275/65R20 | 34.1 in (+0.1%) | 11 in | 609 |
| Nitto Trail Grappler M/T | LT275/65R20 | 34.33 in (+0.7%) | 10.98 in | – |
| Toyo Open Country A/T III | 35X12.50R20LT | 34.5 in (−1.4%) | 12.5 in | 602 |
| Nitto Trail Grappler M/T, load range E | 35x12.50R20LT | 35.04 in (+0.1%) | 13.39 in | – |
| Nitto Trail Grappler M/T, load range F | 35x12.50R20LT | 34.76 in (−0.7%) | 12.52 in | – |
Each size on its own
- 275/65R20 tire size: 34.1 × 10.8 in
- 35x12.50R20 tire size: 35.0 × 12.5 in
Other comparisons
Questions
Can I fit 35x12.50R20 tires instead of 275/65R20?
They fit the same 20-inch wheels. A 35x12.50R20 is 0.93 inches (24 mm) taller and 1.67 inches (42 mm) wider than a 275/65R20, so check three things first: that your wheels are within the 35x12.50R20’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 35x12.50R20 tires?
With a speedometer set for 275/65R20, the speedometer reads low: at 60 mph on it you’re doing 61.6 mph, 2.7% faster. The odometer is off the same way: over 1,000 miles driven it shows 973.6.
Does 35x12.50R20 change the ground clearance?
By +0.46 inches (+12 mm), half the change in diameter, at the axles and at the lowest point under them. 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.