235/80R17 vs 255/80R17
255/80R17 is outside the ±3% rule as a replacement for 235/80R17: the diameter differs by +3.96%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/80R17 on a car calibrated for 235/80R17, the speedometer reads 57.7 mph when you're really doing 60, and the odometer under-counts by 4.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.2 mph |
| 45 mph | 46.8 mph |
| 60 mph | 62.4 mph |
| 70 mph | 72.8 mph |
| 80 mph | 83.2 mph |
Other sizes close to 235/80R17
- 235/80R17 vs 265/70R17-0.62%
- 235/80R17 vs 275/65R18+0.85%
- 235/80R17 vs 265/75R16-0.48%
- 235/80R17 vs 245/70R17-4.09%
- 235/80R17 vs 285/70R17+2.85%
- 235/80R17 vs 265/65R18-0.76%
- 235/80R17 vs 245/75R17-1.05%
- 235/80R17 vs 265/65R17-3.90%
- 235/80R17 vs 235/85R16-0.24%
- 235/80R17 vs 255/70R18+0.79%
- 235/80R17 vs 255/70R17-2.35%
- 235/80R17 vs 255/75R17+0.80%
Questions
Can I replace 235/80R17 with 255/80R17?
255/80R17 is outside the ±3% rule as a replacement for 235/80R17: the diameter differs by +3.96%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 235/80R17 and 255/80R17?
255/80R17 is 1.26" taller and 20 mm wider; the sidewall is +0.63". At an indicated 60 mph you'd actually be doing 62.4 mph.
Will 255/80R17 fit on 235/80R17 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.