ElpiAuto215/45R17 vs 245/45R17
245/45R17 is 1.06″ (27 mm) taller than 215/45R17, a 4.3% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 215/45R17 | 245/45R17 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 24.62″ | 25.68″ | +1.06″ | +4.3% |
| Section width | 8.46″ | 9.65″ | +1.18″ | +14.0% |
| Sidewall height | 3.81″ | 4.34″ | +0.53″ | +14.0% |
| Circumference | 77.34″ | 80.68″ | +3.34″ | +4.3% |
| Revs per mile | 819.2 | 785.3 | −33.9 | −4.1% |
| Revs per km | 509.1 | 488.0 | −21.1 | −4.1% |
Speedometer: with 215/45R17 as the original, 245/45R17 makes an indicated 60 mph really about 62.6 mph, and the axle sits ~0.53″ higher.
Reading this comparison
The overall diameter is what matters here: 245/45R17 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.