225/60R18 vs 255/55R18
255/55R18 is a safe swap for 225/60R18 by the usual ±3% rule: the diameter differs by +1.44%.
Speedometer and odometer
With 255/55R18 on a car calibrated for 225/60R18, the speedometer reads 59.1 mph when you're really doing 60, and the odometer under-counts by 1.4%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.4 mph |
| 45 mph | 45.6 mph |
| 60 mph | 60.9 mph |
| 70 mph | 71.0 mph |
| 80 mph | 81.2 mph |
Other sizes close to 225/60R18
- 225/60R18 vs 235/60R18+1.65%
- 225/60R18 vs 225/65R17-0.40%
- 225/60R18 vs 235/50R18-4.81%
- 225/60R18 vs 235/55R18-1.58%
- 225/60R18 vs 245/60R18+3.30%
- 225/60R18 vs 225/55R18-3.09%
- 225/60R18 vs 235/65R18+4.88%
- 225/60R18 vs 225/55R19+0.40%
- 225/60R18 vs 245/50R18-3.44%
- 225/60R18 vs 215/55R18-4.61%
- 225/60R18 vs 245/50R19+0.06%
- 225/60R18 vs 255/60R18+4.95%
Questions
Can I replace 225/60R18 with 255/55R18?
255/55R18 is a safe swap for 225/60R18 by the usual ±3% rule: the diameter differs by +1.44%.
What's the difference between 225/60R18 and 255/55R18?
255/55R18 is 0.41" taller and 30 mm wider; the sidewall is +0.21". At an indicated 60 mph you'd actually be doing 60.9 mph.
Will 255/55R18 fit on 225/60R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.