235/40R19 vs 245/40R19 tire size
A 245/40R19 is 0.31 inches (8 mm) taller and 0.39 inches (10 mm) wider than a 235/40R19. Fit them in place of 235/40R19 tires and the speedometer reads low: at 60 mph on it you’re doing 60.7 mph, 1.2% faster, and the vehicle sits 0.16 inches (4 mm) higher.
Sources checked
| Dimension | 235/40R19 | 245/40R19 | Change |
|---|---|---|---|
| Overall diameter | 26.40 in (671 mm) | 26.72 in (679 mm) | +0.32 in (+8 mm) |
| Section width | 9.25 in (235 mm) | 9.65 in (245 mm) | +0.40 in (+10 mm) |
| Sidewall height | 3.70 in (94 mm) | 3.86 in (98 mm) | +0.16 in (+4 mm) |
| Aspect ratio | 40% | 40% | |
| Rim diameter | 19 in | 19 in | |
| Circumference | 82.9 in (2,107 mm) | 83.9 in (2,132 mm) | +1.0 in |
| Revolutions per mile | 764 | 755 | −9 |
| Revolutions per km | 475 | 469 | −6 |
Check another speed or size
Metric, LT and flotation
At 60 mph on the speedometer you’re doing
60.7mph
+1.2% · the speedometer reads low
- Height
- +0.31 in (+8 mm)
- Width
- +0.39 in (+10 mm)
- Ground clearance
- +0.16 in (+4 mm)
- Each side, same wheel
- +0.20 in (+5 mm)
235/40R19 and 245/40R19 side by side
| Dimension | 235/40R19 | 245/40R19 | Change |
|---|---|---|---|
| Overall diameter | 26.40 in (671 mm) | 26.72 in (679 mm) | +0.32 in (+8 mm) |
| Section width | 9.25 in (235 mm) | 9.65 in (245 mm) | +0.40 in (+10 mm) |
| Sidewall height | 3.70 in (94 mm) | 3.86 in (98 mm) | +0.16 in (+4 mm) |
| Aspect ratio | 40% | 40% | |
| Rim diameter | 19 in | 19 in | |
| Circumference | 82.9 in | 83.9 in | +1.0 in |
| Revolutions per mile | 764 | 755 | −9 |
| Revolutions per km | 475 | 469 | −6 |
The working
- 235/40R19: sidewall = 235 mm × 40% = 94.0 mm = 3.70 in.
- Diameter = rim + 2 × sidewall = 19 + 2 × 3.70 = 26.40 in (671 mm).
- Circumference = π × 26.40 = 82.9 in; revolutions per mile = 63,360 ÷ 82.9 = 764.
- 245/40R19: sidewall = 245 mm × 40% = 98.0 mm = 3.86 in.
- Diameter = rim + 2 × sidewall = 19 + 2 × 3.86 = 26.72 in (679 mm).
- Circumference = π × 26.72 = 83.9 in; revolutions per mile = 63,360 ÷ 83.9 = 755.
- Speedometer. True speed = what it shows × new diameter ÷ old = 60 × 26.72 ÷ 26.40 = 60.7 mph.
- Ground clearance. Half the change in diameter: (26.72 − 26.40) ÷ 2 = +0.16 in.
Speedometer
A 245/40R19 turns 755 times a mile against the 235/40R19’s 764. With a speedometer set for 235/40R19, true speed is what it shows × 26.72 ÷ 26.40:
| Speedometer shows | True speed | Difference |
|---|---|---|
| 25 mph | 25.3 mph | +0.3 mph |
| 35 mph | 35.4 mph | +0.4 mph |
| 45 mph | 45.5 mph | +0.5 mph |
| 55 mph | 55.7 mph | +0.7 mph |
| 65 mph | 65.8 mph | +0.8 mph |
| 75 mph | 75.9 mph | +0.9 mph |
Clearance
- Ground clearance: +0.16 in (+4 mm), half the change in diameter.
- Top of the tread: +0.16 in (+4 mm), so that much less room under the fender.
- Each side, on the same wheel: +0.20 in (+5 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 3.70 to 3.86 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 Extensa A/S II | 235/40R19 | 26.4 in (0.0%) | 9.5 in | 786 |
| Toyo Proxes Sport A/S | 235/40R19 | 26.4 in (0.0%) | 9.5 in | 786 |
| Toyo Proxes Sport A/S | 245/40R19 | 26.7 in (−0.1%) | 9.8 in | 777 |
Each size on its own
- 235/40R19 tire size: 26.4 × 9.3 in
- 245/40R19 tire size: 26.7 × 9.6 in
Other comparisons
Questions
Can I fit 245/40R19 tires instead of 235/40R19?
They fit the same 19-inch wheels. A 245/40R19 is 0.31 inches (8 mm) taller and 0.39 inches (10 mm) wider than a 235/40R19, so check three things first: that your wheels are within the 245/40R19’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 245/40R19 tires?
With a speedometer set for 235/40R19, the speedometer reads low: at 60 mph on it you’re doing 60.7 mph, 1.2% faster. The odometer is off the same way: over 1,000 miles driven it shows 988.2.
Does 245/40R19 change the ground clearance?
By +0.16 inches (+4 mm), half the change in diameter, at the axles and at the lowest point under them. On the same wheel, each sidewall sits 0.20 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.