ElpiAuto275/65R20 vs 315/60R20
315/60R20 is 0.81″ (21 mm) taller than 275/65R20, a 2.4% difference in overall diameter — right at the edge of the ±3% band — fine on most cars, but check clearance at full lock and full suspension compression.
| Measurement | 275/65R20 | 315/60R20 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 34.07″ | 34.88″ | +0.81″ | +2.4% |
| Section width | 10.83″ | 12.40″ | +1.57″ | +14.5% |
| Sidewall height | 7.04″ | 7.44″ | +0.40″ | +5.7% |
| Circumference | 107.05″ | 109.58″ | +2.54″ | +2.4% |
| Revs per mile | 591.9 | 578.2 | −13.7 | −2.3% |
| Revs per km | 367.8 | 359.3 | −8.5 | −2.3% |
Speedometer: with 275/65R20 as the original, 315/60R20 makes an indicated 60 mph really about 61.4 mph, and the axle sits ~0.40″ higher.
Reading this comparison
The overall diameter is what matters here: 315/60R20 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.