255/35R19 vs 245/40R19
245/40R19 is a safe swap for 255/35R19 by the usual ±3% rule: the diameter differs by +2.65%.
Speedometer and odometer
With 245/40R19 on a car calibrated for 255/35R19, the speedometer reads 58.5 mph when you're really doing 60, and the odometer under-counts by 2.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.8 mph |
| 45 mph | 46.2 mph |
| 60 mph | 61.6 mph |
| 70 mph | 71.9 mph |
| 80 mph | 82.1 mph |
Other sizes close to 255/35R19
- 255/35R19 vs 225/45R18-0.21%
- 255/35R19 vs 235/40R19+1.44%
- 255/35R19 vs 255/40R19+3.86%
- 255/35R19 vs 255/40R18+0.02%
- 255/35R19 vs 275/35R19+2.12%
- 255/35R19 vs 245/35R19-1.06%
- 255/35R19 vs 225/40R19+0.23%
- 255/35R19 vs 235/35R19-2.12%
- 255/35R19 vs 225/45R19+3.63%
- 255/35R19 vs 285/35R19+3.18%
- 255/35R19 vs 265/35R19+1.06%
- 255/35R19 vs 235/45R19+4.99%
Questions
Can I replace 255/35R19 with 245/40R19?
245/40R19 is a safe swap for 255/35R19 by the usual ±3% rule: the diameter differs by +2.65%.
What's the difference between 255/35R19 and 245/40R19?
245/40R19 is 0.69" taller and 10 mm narrower; the sidewall is +0.34". At an indicated 60 mph you'd actually be doing 61.6 mph.
Will 245/40R19 fit on 255/35R19 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.