255/30R19 vs 225/40R19
225/40R19 is outside the ±3% rule as a replacement for 255/30R19: the diameter differs by +4.25%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 225/40R19 on a car calibrated for 255/30R19, the speedometer reads 57.6 mph when you're really doing 60, and the odometer under-counts by 4.2%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.3 mph |
| 45 mph | 46.9 mph |
| 60 mph | 62.5 mph |
| 70 mph | 73.0 mph |
| 80 mph | 83.4 mph |
Other sizes close to 255/30R19
- 255/30R19 vs 225/40R18+0.25%
- 255/30R19 vs 255/35R19+4.01%
- 255/30R19 vs 255/35R18+0.02%
- 255/30R19 vs 245/35R19+2.91%
- 255/30R19 vs 235/35R19+1.81%
- 255/30R19 vs 285/30R19+2.83%
- 255/30R19 vs 225/35R19+0.71%
- 255/30R19 vs 305/30R19+4.72%
- 255/30R19 vs 295/30R19+3.78%
- 255/30R19 vs 275/30R19+1.89%
- 255/30R19 vs 265/30R19+0.94%
- 255/30R19 vs 295/30R18-0.22%
Questions
Can I replace 255/30R19 with 225/40R19?
225/40R19 is outside the ±3% rule as a replacement for 255/30R19: the diameter differs by +4.25%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 255/30R19 and 225/40R19?
225/40R19 is 1.06" taller and 30 mm narrower; the sidewall is +0.53". At an indicated 60 mph you'd actually be doing 62.5 mph.
Will 225/40R19 fit on 255/30R19 wheels?
Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.