275/55R17 vs 235/60R18
235/60R18 is a safe swap for 275/55R17 by the usual ±3% rule: the diameter differs by +0.67%.
Speedometer and odometer
With 235/60R18 on a car calibrated for 275/55R17, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.7%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.3 mph |
| 60 mph | 60.4 mph |
| 70 mph | 70.5 mph |
| 80 mph | 80.5 mph |
Other sizes close to 275/55R17
- 275/55R17 vs 225/65R17-1.36%
- 275/55R17 vs 235/65R17+0.41%
- 275/55R17 vs 225/60R18-0.97%
- 275/55R17 vs 225/60R17-4.43%
- 275/55R17 vs 245/65R17+2.18%
- 275/55R17 vs 255/55R18+0.46%
- 275/55R17 vs 235/70R16+0.15%
- 275/55R17 vs 235/60R17-2.79%
- 275/55R17 vs 215/65R17-3.13%
- 275/55R17 vs 255/65R17+3.95%
- 275/55R17 vs 235/70R17+3.61%
- 275/55R17 vs 255/65R16+0.49%
Questions
Can I replace 275/55R17 with 235/60R18?
235/60R18 is a safe swap for 275/55R17 by the usual ±3% rule: the diameter differs by +0.67%.
What's the difference between 275/55R17 and 235/60R18?
235/60R18 is 0.19" taller and 40 mm narrower; the sidewall is -0.40". At an indicated 60 mph you'd actually be doing 60.4 mph.
Will 235/60R18 fit on 275/55R17 wheels?
No — 275/55R17 needs a 17" wheel and 235/60R18 a 18" wheel. This is a plus/minus-size swap that changes wheels too.