245/45R19 vs 255/50R19
255/50R19 is outside the ±3% rule as a replacement for 245/45R19: the diameter differs by +4.91%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/50R19 on a car calibrated for 245/45R19, the speedometer reads 57.2 mph when you're really doing 60, and the odometer under-counts by 4.9%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.2 mph |
| 60 mph | 62.9 mph |
| 70 mph | 73.4 mph |
| 80 mph | 83.9 mph |
Other sizes close to 245/45R19
- 245/45R19 vs 245/40R19-3.48%
- 245/45R19 vs 235/40R19-4.62%
- 245/45R19 vs 255/40R19-2.35%
- 245/45R19 vs 225/55R18+0.23%
- 245/45R19 vs 245/40R20+0.13%
- 245/45R19 vs 255/45R19+1.28%
- 245/45R19 vs 275/35R19-3.98%
- 245/45R19 vs 225/55R19+3.84%
- 245/45R19 vs 275/40R19-0.07%
- 245/45R19 vs 275/35R20-0.37%
- 245/45R19 vs 225/45R19-2.56%
- 245/45R19 vs 245/50R18-0.13%
Questions
Can I replace 245/45R19 with 255/50R19?
255/50R19 is outside the ±3% rule as a replacement for 245/45R19: the diameter differs by +4.91%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 245/45R19 and 255/50R19?
255/50R19 is 1.36" taller and 10 mm wider; the sidewall is +0.68". At an indicated 60 mph you'd actually be doing 62.9 mph.
Will 255/50R19 fit on 245/45R19 wheels?
Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.