205/50R17 vs 255/45R17
255/45R17 is outside the ±3% rule as a replacement for 205/50R17: the diameter differs by +3.85%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/45R17 on a car calibrated for 205/50R17, the speedometer reads 57.8 mph when you're really doing 60, and the odometer under-counts by 3.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.2 mph |
| 45 mph | 46.7 mph |
| 60 mph | 62.3 mph |
| 70 mph | 72.7 mph |
| 80 mph | 83.1 mph |
Other sizes close to 205/50R17
- 205/50R17 vs 225/45R17-0.39%
- 205/50R17 vs 225/40R18+0.06%
- 205/50R17 vs 225/50R17+3.14%
- 205/50R17 vs 205/55R16-0.77%
- 205/50R17 vs 215/45R17-1.81%
- 205/50R17 vs 215/55R17+4.95%
- 205/50R17 vs 215/50R17+1.57%
- 205/50R17 vs 235/45R17+1.02%
- 205/50R17 vs 245/45R17+2.43%
- 205/50R17 vs 215/55R16+0.96%
- 205/50R17 vs 255/35R18-0.17%
- 205/50R17 vs 245/40R17-1.41%
Questions
Can I replace 205/50R17 with 255/45R17?
255/45R17 is outside the ±3% rule as a replacement for 205/50R17: the diameter differs by +3.85%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 205/50R17 and 255/45R17?
255/45R17 is 0.96" taller and 50 mm wider; the sidewall is +0.48". At an indicated 60 mph you'd actually be doing 62.3 mph.
Will 255/45R17 fit on 205/50R17 wheels?
Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 255 mm tire and the fender clearance.