265/40R19 vs 255/45R19
255/45R19 is a safe swap for 265/40R19 by the usual ±3% rule: the diameter differs by +2.52%.
Speedometer and odometer
With 255/45R19 on a car calibrated for 265/40R19, the speedometer reads 58.5 mph when you're really doing 60, and the odometer under-counts by 2.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.8 mph |
| 45 mph | 46.1 mph |
| 60 mph | 61.5 mph |
| 70 mph | 71.8 mph |
| 80 mph | 82.0 mph |
Other sizes close to 265/40R19
- 265/40R19 vs 235/50R18-0.35%
- 265/40R19 vs 245/45R19+1.22%
- 265/40R19 vs 245/40R19-2.30%
- 265/40R19 vs 235/40R19-3.46%
- 265/40R19 vs 255/40R19-1.15%
- 265/40R19 vs 255/35R19-4.82%
- 265/40R19 vs 275/35R19-2.81%
- 265/40R19 vs 275/40R19+1.15%
- 265/40R19 vs 225/40R19-4.61%
- 265/40R19 vs 275/35R20+0.85%
- 265/40R19 vs 225/45R19-1.37%
- 265/40R19 vs 235/50R19+3.31%
Questions
Can I replace 265/40R19 with 255/45R19?
255/45R19 is a safe swap for 265/40R19 by the usual ±3% rule: the diameter differs by +2.52%.
What's the difference between 265/40R19 and 255/45R19?
255/45R19 is 0.69" taller and 10 mm narrower; the sidewall is +0.34". At an indicated 60 mph you'd actually be doing 61.5 mph.
Will 255/45R19 fit on 265/40R19 wheels?
Both use a 19" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.