ElpiAuto275/65R18 vs 325/60R18
325/60R18 is 1.28″ (33 mm) taller than 275/65R18, a 4.0% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 275/65R18 | 325/60R18 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 32.07″ | 33.35″ | +1.28″ | +4.0% |
| Section width | 10.83″ | 12.80″ | +1.97″ | +18.2% |
| Sidewall height | 7.04″ | 7.68″ | +0.64″ | +9.1% |
| Circumference | 100.77″ | 104.79″ | +4.02″ | +4.0% |
| Revs per mile | 628.8 | 604.7 | −24.1 | −3.8% |
| Revs per km | 390.7 | 375.7 | −15.0 | −3.8% |
Speedometer: with 275/65R18 as the original, 325/60R18 makes an indicated 60 mph really about 62.4 mph, and the axle sits ~0.64″ higher.
Reading this comparison
The overall diameter is what matters here: 325/60R18 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.