225/45R19 vs 255/45R18
255/45R18 is a safe swap for 225/45R19 by the usual ±3% rule: the diameter differs by +0.23%.
Speedometer and odometer
With 255/45R18 on a car calibrated for 225/45R19, the speedometer reads 59.9 mph when you're really doing 60, and the odometer under-counts by 0.2%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.1 mph |
| 60 mph | 60.1 mph |
| 70 mph | 70.2 mph |
| 80 mph | 80.2 mph |
Other sizes close to 225/45R19
- 225/45R19 vs 245/45R19+2.63%
- 225/45R19 vs 245/40R19-0.95%
- 225/45R19 vs 225/50R18-0.42%
- 225/45R19 vs 235/40R19-2.12%
- 225/45R19 vs 255/40R19+0.22%
- 225/45R19 vs 255/35R19-3.50%
- 225/45R19 vs 255/45R19+3.94%
- 225/45R19 vs 275/35R19-1.46%
- 225/45R19 vs 275/40R19+2.55%
- 225/45R19 vs 245/35R20-0.82%
- 225/45R19 vs 245/35R19-4.52%
- 225/45R19 vs 255/35R20+0.20%
Questions
Can I replace 225/45R19 with 255/45R18?
255/45R18 is a safe swap for 225/45R19 by the usual ±3% rule: the diameter differs by +0.23%.
What's the difference between 225/45R19 and 255/45R18?
255/45R18 is 0.06" taller and 30 mm wider; the sidewall is +0.53". At an indicated 60 mph you'd actually be doing 60.1 mph.
Will 255/45R18 fit on 225/45R19 wheels?
No — 225/45R19 needs a 19" wheel and 255/45R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.