255/65R17 vs 255/70R17
255/70R17 is outside the ±3% rule as a replacement for 255/65R17: the diameter differs by +3.34%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/70R17 on a car calibrated for 255/65R17, the speedometer reads 58.1 mph when you're really doing 60, and the odometer under-counts by 3.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.0 mph |
| 45 mph | 46.5 mph |
| 60 mph | 62.0 mph |
| 70 mph | 72.3 mph |
| 80 mph | 82.7 mph |
Other sizes close to 255/65R17
- 255/65R17 vs 235/65R17-3.41%
- 255/65R17 vs 245/70R17+1.51%
- 255/65R17 vs 245/65R17-1.70%
- 255/65R17 vs 245/75R17+4.72%
- 255/65R17 vs 235/65R18-0.08%
- 255/65R17 vs 265/65R17+1.70%
- 255/65R17 vs 255/70R16+0.01%
- 255/65R17 vs 255/60R18-0.01%
- 255/65R17 vs 235/75R17+2.75%
- 255/65R17 vs 235/70R17-0.33%
- 255/65R17 vs 235/75R16-0.58%
- 255/65R17 vs 255/60R17-3.34%
Questions
Can I replace 255/65R17 with 255/70R17?
255/70R17 is outside the ±3% rule as a replacement for 255/65R17: the diameter differs by +3.34%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 255/65R17 and 255/70R17?
255/70R17 is 1.00" taller and 0 mm wider; the sidewall is +0.50". At an indicated 60 mph you'd actually be doing 62.0 mph.
Will 255/70R17 fit on 255/65R17 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.