215/55R18 vs 245/50R18
245/50R18 is a safe swap for 215/55R18 by the usual ±3% rule: the diameter differs by +1.23%.
Speedometer and odometer
With 245/50R18 on a car calibrated for 215/55R18, the speedometer reads 59.3 mph when you're really doing 60, and the odometer under-counts by 1.2%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.4 mph |
| 45 mph | 45.6 mph |
| 60 mph | 60.7 mph |
| 70 mph | 70.9 mph |
| 80 mph | 81.0 mph |
Other sizes close to 215/55R18
- 215/55R18 vs 225/45R18-4.90%
- 215/55R18 vs 245/45R18-2.31%
- 215/55R18 vs 235/50R18-0.22%
- 215/55R18 vs 235/55R18+3.17%
- 215/55R18 vs 235/45R18-3.60%
- 215/55R18 vs 235/55R17-0.49%
- 215/55R18 vs 225/60R18+4.83%
- 215/55R18 vs 225/50R18-1.66%
- 215/55R18 vs 225/55R18+1.59%
- 215/55R18 vs 255/40R18-4.69%
- 215/55R18 vs 215/60R17-0.56%
- 215/55R18 vs 255/45R18-1.01%
Questions
Can I replace 215/55R18 with 245/50R18?
245/50R18 is a safe swap for 215/55R18 by the usual ±3% rule: the diameter differs by +1.23%.
What's the difference between 215/55R18 and 245/50R18?
245/50R18 is 0.33" taller and 30 mm wider; the sidewall is +0.17". At an indicated 60 mph you'd actually be doing 60.7 mph.
Will 245/50R18 fit on 215/55R18 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.