ElpiAuto285/70R17 vs 235/75R17
235/75R17 is 1.83″ (47 mm) shorter than 285/70R17, a 5.6% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 285/70R17 | 235/75R17 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 32.71″ | 30.88″ | −1.83″ | −5.6% |
| Section width | 11.22″ | 9.25″ | −1.97″ | −17.5% |
| Sidewall height | 7.85″ | 6.94″ | −0.92″ | −11.7% |
| Circumference | 102.76″ | 97.01″ | −5.75″ | −5.6% |
| Revs per mile | 616.6 | 653.2 | +36.6 | +5.9% |
| Revs per km | 383.1 | 405.9 | +22.7 | +5.9% |
Speedometer: with 285/70R17 as the original, 235/75R17 makes an indicated 60 mph really about 56.6 mph, and the axle sits ~0.92″ lower.
Reading this comparison
The overall diameter is what matters here: 285/70R17 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.