ElpiAuto31X10.50R15 vs 35X12.50R15
35X12.50R15 is 4.00″ (102 mm) taller than 31X10.50R15, a 12.9% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 31X10.50R15 | 35X12.50R15 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 31.00″ | 35.00″ | +4.00″ | +12.9% |
| Section width | 10.50″ | 12.50″ | +2.00″ | +19.0% |
| Sidewall height | 8.00″ | 10.00″ | +2.00″ | +25.0% |
| Circumference | 97.39″ | 109.96″ | +12.57″ | +12.9% |
| Revs per mile | 650.6 | 576.2 | −74.4 | −11.4% |
| Revs per km | 404.3 | 358.1 | −46.2 | −11.4% |
Speedometer: with 31X10.50R15 as the original, 35X12.50R15 makes an indicated 60 mph really about 67.7 mph, and the axle sits ~2.00″ higher.
Reading this comparison
The overall diameter is what matters here: 35X12.50R15 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.