ElpiAuto235/75R17 vs 245/75R17
245/75R17 is 0.59″ (15 mm) taller than 235/75R17, a 1.9% difference in overall diameter — right at the edge of the ±3% band — fine on most cars, but check clearance at full lock and full suspension compression.
| Measurement | 235/75R17 | 245/75R17 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 30.88″ | 31.47″ | +0.59″ | +1.9% |
| Section width | 9.25″ | 9.65″ | +0.39″ | +4.3% |
| Sidewall height | 6.94″ | 7.23″ | +0.30″ | +4.3% |
| Circumference | 97.01″ | 98.86″ | +1.86″ | +1.9% |
| Revs per mile | 653.2 | 640.9 | −12.3 | −1.9% |
| Revs per km | 405.9 | 398.2 | −7.6 | −1.9% |
Speedometer: with 235/75R17 as the original, 245/75R17 makes an indicated 60 mph really about 61.1 mph, and the axle sits ~0.30″ higher.
Reading this comparison
The overall diameter is what matters here: 245/75R17 is the taller tire. It sets ride height, gearing and how far the tire travels per revolution — which is what the speedometer and odometer count. Width and sidewall change fit and feel (a wider tire needs a wider wheel and more clearance; a shorter sidewall sharpens steering) but not the gearing.
Figures are geometric estimates from the size codes; real moulded tires vary by brand by 1–3%. Confirm load rating, wheel width and physical clearance on your vehicle before fitting. To compare any other two sizes, use the tire size comparison tool; to decode one size and see what else fits its wheel, the tire size calculator.