235/65R17 vs 245/65R17 tire size
A 245/65R17 is 0.51 inches (13 mm) taller and 0.39 inches (10 mm) wider than a 235/65R17. Fit them in place of 235/65R17 tires and the speedometer reads low: at 60 mph on it you’re doing 61.1 mph, 1.8% faster, and the vehicle sits 0.26 inches (6 mm) higher.
Sources checked
| Dimension | 235/65R17 | 245/65R17 | Change |
|---|---|---|---|
| Overall diameter | 29.03 in (737 mm) | 29.54 in (750 mm) | +0.51 in (+13 mm) |
| Section width | 9.25 in (235 mm) | 9.65 in (245 mm) | +0.40 in (+10 mm) |
| Sidewall height | 6.01 in (153 mm) | 6.27 in (159 mm) | +0.26 in (+6 mm) |
| Aspect ratio | 65% | 65% | |
| Rim diameter | 17 in | 17 in | |
| Circumference | 91.2 in (2,316 mm) | 92.8 in (2,357 mm) | +1.6 in |
| Revolutions per mile | 695 | 683 | −12 |
| Revolutions per km | 432 | 424 | −8 |
Check another speed or size
Metric, LT and flotation
At 60 mph on the speedometer you’re doing
61.1mph
+1.8% · the speedometer reads low
- Height
- +0.51 in (+13 mm)
- Width
- +0.39 in (+10 mm)
- Ground clearance
- +0.26 in (+6 mm)
- Each side, same wheel
- +0.20 in (+5 mm)
235/65R17 and 245/65R17 side by side
| Dimension | 235/65R17 | 245/65R17 | Change |
|---|---|---|---|
| Overall diameter | 29.03 in (737 mm) | 29.54 in (750 mm) | +0.51 in (+13 mm) |
| Section width | 9.25 in (235 mm) | 9.65 in (245 mm) | +0.40 in (+10 mm) |
| Sidewall height | 6.01 in (153 mm) | 6.27 in (159 mm) | +0.26 in (+6 mm) |
| Aspect ratio | 65% | 65% | |
| Rim diameter | 17 in | 17 in | |
| Circumference | 91.2 in | 92.8 in | +1.6 in |
| Revolutions per mile | 695 | 683 | −12 |
| Revolutions per km | 432 | 424 | −8 |
The working
- 235/65R17: sidewall = 235 mm × 65% = 152.8 mm = 6.01 in.
- Diameter = rim + 2 × sidewall = 17 + 2 × 6.01 = 29.03 in (737 mm).
- Circumference = π × 29.03 = 91.2 in; revolutions per mile = 63,360 ÷ 91.2 = 695.
- 245/65R17: sidewall = 245 mm × 65% = 159.3 mm = 6.27 in.
- Diameter = rim + 2 × sidewall = 17 + 2 × 6.27 = 29.54 in (750 mm).
- Circumference = π × 29.54 = 92.8 in; revolutions per mile = 63,360 ÷ 92.8 = 683.
- Speedometer. True speed = what it shows × new diameter ÷ old = 60 × 29.54 ÷ 29.03 = 61.1 mph.
- Ground clearance. Half the change in diameter: (29.54 − 29.03) ÷ 2 = +0.26 in.
Speedometer
A 245/65R17 turns 683 times a mile against the 235/65R17’s 695. With a speedometer set for 235/65R17, true speed is what it shows × 29.54 ÷ 29.03:
| Speedometer shows | True speed | Difference |
|---|---|---|
| 25 mph | 25.4 mph | +0.4 mph |
| 35 mph | 35.6 mph | +0.6 mph |
| 45 mph | 45.8 mph | +0.8 mph |
| 55 mph | 56.0 mph | +1.0 mph |
| 65 mph | 66.1 mph | +1.1 mph |
| 75 mph | 76.3 mph | +1.3 mph |
Clearance
- Ground clearance: +0.26 in (+6 mm), half the change in diameter.
- Top of the tread: +0.26 in (+6 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 6.01 to 6.27 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 | 235/65R17 | 29.1 in (+0.2%) | 9.4 in | 715 |
| Toyo Open Country A/T III | 235/65R17 | 29.1 in (+0.2%) | 9.4 in | 715 |
| Toyo Open Country A/T III | 245/65R17 | 29.5 in (−0.1%) | 9.8 in | 704 |
| Toyo Open Country A/T III | LT245/65R17 | 29.5 in (−0.1%) | 9.8 in | 704 |
Each size on its own
- 235/65R17 tire size: 29.0 × 9.3 in
- 245/65R17 tire size: 29.5 × 9.6 in
Other comparisons
Questions
Can I fit 245/65R17 tires instead of 235/65R17?
They fit the same 17-inch wheels. A 245/65R17 is 0.51 inches (13 mm) taller and 0.39 inches (10 mm) wider than a 235/65R17, so check three things first: that your wheels are within the 245/65R17’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 245/65R17 tires?
With a speedometer set for 235/65R17, the speedometer reads low: at 60 mph on it you’re doing 61.1 mph, 1.8% faster. The odometer is off the same way: over 1,000 miles driven it shows 982.7.
Does 245/65R17 change the ground clearance?
By +0.26 inches (+6 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.