225/65R17 vs 245/55R18
245/55R18 is a safe swap for 225/65R17 by the usual ±3% rule: the diameter differs by +0.33%.
Speedometer and odometer
With 245/55R18 on a car calibrated for 225/65R17, the speedometer reads 59.8 mph when you're really doing 60, and the odometer under-counts by 0.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.1 mph |
| 45 mph | 45.1 mph |
| 60 mph | 60.2 mph |
| 70 mph | 70.2 mph |
| 80 mph | 80.3 mph |
Other sizes close to 225/65R17
- 225/65R17 vs 235/65R17+1.79%
- 225/65R17 vs 235/55R17-4.69%
- 225/65R17 vs 225/60R18+0.40%
- 225/65R17 vs 225/60R17-3.11%
- 225/65R17 vs 245/65R17+3.59%
- 225/65R17 vs 235/60R17-1.45%
- 225/65R17 vs 215/65R17-1.79%
- 225/65R17 vs 215/60R17-4.76%
- 225/65R17 vs 225/70R16-0.40%
- 225/65R17 vs 255/60R17+1.86%
- 225/65R17 vs 275/55R17+1.38%
Questions
Can I replace 225/65R17 with 245/55R18?
245/55R18 is a safe swap for 225/65R17 by the usual ±3% rule: the diameter differs by +0.33%.
What's the difference between 225/65R17 and 245/55R18?
245/55R18 is 0.09" taller and 20 mm wider; the sidewall is -0.45". At an indicated 60 mph you'd actually be doing 60.2 mph.
Will 245/55R18 fit on 225/65R17 wheels?
No — 225/65R17 needs a 17" wheel and 245/55R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.