265/45R18 vs 245/55R18
245/55R18 is outside the ±3% rule as a replacement for 265/45R18: the diameter differs by +4.46%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 245/55R18 on a car calibrated for 265/45R18, the speedometer reads 57.4 mph when you're really doing 60, and the odometer under-counts by 4.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.3 mph |
| 45 mph | 47.0 mph |
| 60 mph | 62.7 mph |
| 70 mph | 73.1 mph |
| 80 mph | 83.6 mph |
Other sizes close to 265/45R18
- 265/45R18 vs 245/45R18-2.59%
- 265/45R18 vs 235/50R18-0.50%
- 265/45R18 vs 235/55R18+2.87%
- 265/45R18 vs 235/45R18-3.88%
- 265/45R18 vs 235/55R17-0.78%
- 265/45R18 vs 225/60R18+4.53%
- 265/45R18 vs 225/50R18-1.94%
- 265/45R18 vs 225/60R17+0.88%
- 265/45R18 vs 225/55R18+1.29%
- 265/45R18 vs 255/40R18-4.96%
- 265/45R18 vs 275/40R19+0.99%
- 265/45R18 vs 215/60R17-0.85%
Questions
Can I replace 265/45R18 with 245/55R18?
245/55R18 is outside the ±3% rule as a replacement for 265/45R18: the diameter differs by +4.46%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 265/45R18 and 245/55R18?
245/55R18 is 1.22" taller and 20 mm narrower; the sidewall is +0.61". At an indicated 60 mph you'd actually be doing 62.7 mph.
Will 245/55R18 fit on 265/45R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.