265/45R18 vs 235/55R18
235/55R18 is a safe swap for 265/45R18 by the usual ±3% rule: the diameter differs by +2.87%.
Speedometer and odometer
With 235/55R18 on a car calibrated for 265/45R18, the speedometer reads 58.3 mph when you're really doing 60, and the odometer under-counts by 2.9%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.9 mph |
| 45 mph | 46.3 mph |
| 60 mph | 61.7 mph |
| 70 mph | 72.0 mph |
| 80 mph | 82.3 mph |
Other sizes close to 265/45R18
- 265/45R18 vs 245/45R18-2.59%
- 265/45R18 vs 235/50R18-0.50%
- 265/45R18 vs 235/45R18-3.88%
- 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%
- 265/45R18 vs 245/50R18+0.93%
Questions
Can I replace 265/45R18 with 235/55R18?
235/55R18 is a safe swap for 265/45R18 by the usual ±3% rule: the diameter differs by +2.87%.
What's the difference between 265/45R18 and 235/55R18?
235/55R18 is 0.79" taller and 30 mm narrower; the sidewall is +0.39". At an indicated 60 mph you'd actually be doing 61.7 mph.
Will 235/55R18 fit on 265/45R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.