ElpiAuto325/60R18 vs 35X12.50R18
35X12.50R18 is 1.65″ (42 mm) taller than 325/60R18, a 4.9% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 325/60R18 | 35X12.50R18 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 33.35″ | 35.00″ | +1.65″ | +4.9% |
| Section width | 12.80″ | 12.50″ | −0.30″ | −2.3% |
| Sidewall height | 7.68″ | 8.50″ | +0.82″ | +10.7% |
| Circumference | 104.79″ | 109.96″ | +5.17″ | +4.9% |
| Revs per mile | 604.7 | 576.2 | −28.4 | −4.7% |
| Revs per km | 375.7 | 358.1 | −17.7 | −4.7% |
Speedometer: with 325/60R18 as the original, 35X12.50R18 makes an indicated 60 mph really about 63.0 mph, and the axle sits ~0.82″ higher.
Reading this comparison
The overall diameter is what matters here: 35X12.50R18 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.