245/45R19 vs 285/40R19
285/40R19 is a safe swap for 245/45R19 by the usual ±3% rule: the diameter differs by +1.07%.
Speedometer and odometer
With 285/40R19 on a car calibrated for 245/45R19, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.3 mph |
| 45 mph | 45.5 mph |
| 60 mph | 60.6 mph |
| 70 mph | 70.7 mph |
| 80 mph | 80.9 mph |
Other sizes close to 245/45R19
- 245/45R19 vs 245/40R19-3.48%
- 245/45R19 vs 255/50R19+4.91%
- 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%
Questions
Can I replace 245/45R19 with 285/40R19?
285/40R19 is a safe swap for 245/45R19 by the usual ±3% rule: the diameter differs by +1.07%.
What's the difference between 245/45R19 and 285/40R19?
285/40R19 is 0.30" taller and 40 mm wider; the sidewall is +0.15". At an indicated 60 mph you'd actually be doing 60.6 mph.
Will 285/40R19 fit on 245/45R19 wheels?
Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 285 mm tire and the fender clearance.