255/45R17 vs 235/55R17
235/55R17 is outside the ±3% rule as a replacement for 255/45R17: the diameter differs by +4.39%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 235/55R17 on a car calibrated for 255/45R17, the speedometer reads 57.5 mph when you're really doing 60, and the odometer under-counts by 4.4%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.3 mph |
| 45 mph | 47.0 mph |
| 60 mph | 62.6 mph |
| 70 mph | 73.1 mph |
| 80 mph | 83.5 mph |
Other sizes close to 255/45R17
- 255/45R17 vs 225/45R17-4.08%
- 255/45R17 vs 225/45R18-0.24%
- 255/45R17 vs 225/50R17-0.68%
- 255/45R17 vs 225/55R17+2.72%
- 255/45R17 vs 205/50R17-3.70%
- 255/45R17 vs 215/55R17+1.06%
- 255/45R17 vs 215/50R17-2.19%
- 255/45R17 vs 235/45R17-2.72%
- 255/45R17 vs 245/45R17-1.36%
- 255/45R17 vs 215/60R16+0.47%
- 255/45R17 vs 255/40R18-0.02%
- 255/45R17 vs 215/60R17+4.31%
Questions
Can I replace 255/45R17 with 235/55R17?
235/55R17 is outside the ±3% rule as a replacement for 255/45R17: the diameter differs by +4.39%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 255/45R17 and 235/55R17?
235/55R17 is 1.14" taller and 20 mm narrower; the sidewall is +0.57". At an indicated 60 mph you'd actually be doing 62.6 mph.
Will 235/55R17 fit on 255/45R17 wheels?
Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.