235/60R17 vs 235/55R18
235/55R18 is a safe swap for 235/60R17 by the usual ±3% rule: the diameter differs by +0.27%.
Speedometer and odometer
With 235/55R18 on a car calibrated for 235/60R17, 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 | 80.2 mph |
Other sizes close to 235/60R17
- 235/60R17 vs 225/55R17-4.83%
- 235/60R17 vs 225/65R17+1.47%
- 235/60R17 vs 235/65R17+3.29%
- 235/60R17 vs 235/55R17-3.29%
- 235/60R17 vs 225/60R17-1.68%
- 235/60R17 vs 215/65R17-0.35%
- 235/60R17 vs 215/70R16-0.90%
- 235/60R17 vs 215/60R17-3.36%
- 235/60R17 vs 235/65R16-0.27%
- 235/60R17 vs 255/60R17+3.36%
- 235/60R17 vs 275/55R17+2.87%
Questions
Can I replace 235/60R17 with 235/55R18?
235/55R18 is a safe swap for 235/60R17 by the usual ±3% rule: the diameter differs by +0.27%.
What's the difference between 235/60R17 and 235/55R18?
235/55R18 is 0.07" taller and 0 mm wider; the sidewall is -0.46". At an indicated 60 mph you'd actually be doing 60.2 mph.
Will 235/55R18 fit on 235/60R17 wheels?
No — 235/60R17 needs a 17" wheel and 235/55R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.