285/30R19 vs 245/40R19
245/40R19 is outside the ±3% rule as a replacement for 285/30R19: the diameter differs by +3.82%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 245/40R19 on a car calibrated for 285/30R19, the speedometer reads 57.8 mph when you're really doing 60, and the odometer under-counts by 3.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.1 mph |
| 45 mph | 46.7 mph |
| 60 mph | 62.3 mph |
| 70 mph | 72.7 mph |
| 80 mph | 83.1 mph |
Other sizes close to 285/30R19
- 285/30R19 vs 245/40R18-0.06%
- 285/30R19 vs 225/45R18+0.93%
- 285/30R19 vs 235/40R19+2.60%
- 285/30R19 vs 255/35R19+1.15%
- 285/30R19 vs 275/35R19+3.29%
- 285/30R19 vs 245/35R19+0.08%
- 285/30R19 vs 225/40R19+1.38%
- 285/30R19 vs 235/35R19-0.99%
- 285/30R19 vs 225/45R19+4.82%
- 285/30R19 vs 275/35R18-0.60%
- 285/30R19 vs 285/35R19+4.36%
- 285/30R19 vs 265/35R19+2.22%
Questions
Can I replace 285/30R19 with 245/40R19?
245/40R19 is outside the ±3% rule as a replacement for 285/30R19: the diameter differs by +3.82%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 285/30R19 and 245/40R19?
245/40R19 is 0.98" taller and 40 mm narrower; the sidewall is +0.49". At an indicated 60 mph you'd actually be doing 62.3 mph.
Will 245/40R19 fit on 285/30R19 wheels?
Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.