275/30R19 vs 245/40R19
245/40R19 is outside the ±3% rule as a replacement for 275/30R19: the diameter differs by +4.79%, 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 275/30R19, the speedometer reads 57.3 mph when you're really doing 60, and the odometer under-counts by 4.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.4 mph |
| 45 mph | 47.2 mph |
| 60 mph | 62.9 mph |
| 70 mph | 73.4 mph |
| 80 mph | 83.8 mph |
Other sizes close to 275/30R19
- 275/30R19 vs 245/40R18+0.86%
- 275/30R19 vs 235/40R18-0.37%
- 275/30R19 vs 235/40R19+3.55%
- 275/30R19 vs 255/35R19+2.08%
- 275/30R19 vs 275/35R19+4.25%
- 275/30R19 vs 245/35R19+1.00%
- 275/30R19 vs 225/40R19+2.32%
- 275/30R19 vs 235/35R19-0.08%
- 275/30R19 vs 275/35R18+0.32%
- 275/30R19 vs 265/35R18-0.76%
- 275/30R19 vs 265/35R19+3.17%
- 275/30R19 vs 215/45R18+0.48%
Questions
Can I replace 275/30R19 with 245/40R19?
245/40R19 is outside the ±3% rule as a replacement for 275/30R19: the diameter differs by +4.79%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 275/30R19 and 245/40R19?
245/40R19 is 1.22" taller and 30 mm narrower; the sidewall is +0.61". At an indicated 60 mph you'd actually be doing 62.9 mph.
Will 245/40R19 fit on 275/30R19 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.