285/70R17 vs 255/80R17
255/80R17 is a safe swap for 285/70R17 by the usual ±3% rule: the diameter differs by +1.08%.
Speedometer and odometer
With 255/80R17 on a car calibrated for 285/70R17, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.3 mph |
| 45 mph | 45.5 mph |
| 60 mph | 60.6 mph |
| 70 mph | 70.8 mph |
| 80 mph | 80.9 mph |
Other sizes close to 285/70R17
- 285/70R17 vs 265/70R17-3.37%
- 285/70R17 vs 245/75R17-3.79%
- 285/70R17 vs 265/70R18-0.31%
- 285/70R17 vs 235/80R17-2.77%
- 285/70R17 vs 285/75R16+0.37%
- 285/70R17 vs 285/65R18-0.37%
- 285/70R17 vs 255/75R17-1.99%
- 285/70R17 vs 295/70R17+1.69%
- 285/70R17 vs 305/70R16+0.31%
- 285/70R17 vs 33x12.50R18+0.89%
- 285/70R17 vs 285/75R17+3.43%
- 285/70R17 vs 33x12.50R17+0.89%
Questions
Can I replace 285/70R17 with 255/80R17?
255/80R17 is a safe swap for 285/70R17 by the usual ±3% rule: the diameter differs by +1.08%.
What's the difference between 285/70R17 and 255/80R17?
255/80R17 is 0.35" taller and 30 mm narrower; the sidewall is +0.18". At an indicated 60 mph you'd actually be doing 60.6 mph.
Will 255/80R17 fit on 285/70R17 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.