ElpiAuto295/65R18 vs 305/70R18
305/70R18 is 1.71″ (44 mm) taller than 295/65R18, a 5.2% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 295/65R18 | 305/70R18 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 33.10″ | 34.81″ | +1.71″ | +5.2% |
| Section width | 11.61″ | 12.01″ | +0.39″ | +3.4% |
| Sidewall height | 7.55″ | 8.41″ | +0.86″ | +11.3% |
| Circumference | 103.98″ | 109.36″ | +5.38″ | +5.2% |
| Revs per mile | 609.3 | 579.4 | −30.0 | −4.9% |
| Revs per km | 378.6 | 360.0 | −18.6 | −4.9% |
Speedometer: with 295/65R18 as the original, 305/70R18 makes an indicated 60 mph really about 63.1 mph, and the axle sits ~0.86″ higher.
Reading this comparison
The overall diameter is what matters here: 305/70R18 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.