ElpiAuto235/50R18 vs 245/45R19
245/45R19 is 0.43″ (11 mm) taller than 235/50R18, a 1.6% 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.
These sit on different wheel sizes — you'd be changing wheels too, not just tires.
| Measurement | 235/50R18 | 245/45R19 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 27.25″ | 27.68″ | +0.43″ | +1.6% |
| Section width | 9.25″ | 9.65″ | +0.39″ | +4.3% |
| Sidewall height | 4.63″ | 4.34″ | −0.29″ | −6.2% |
| Circumference | 85.61″ | 86.96″ | +1.35″ | +1.6% |
| Revs per mile | 740.1 | 728.6 | −11.5 | −1.6% |
| Revs per km | 459.9 | 452.7 | −7.1 | −1.6% |
Speedometer: with 235/50R18 as the original, 245/45R19 makes an indicated 60 mph really about 60.9 mph, and the axle sits ~0.21″ higher.
Reading this comparison
The overall diameter is what matters here: 245/45R19 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.