255/60R17 vs 245/70R17
245/70R17 is outside the ±3% rule as a replacement for 255/60R17: the diameter differs by +5.01%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 245/70R17 on a car calibrated for 255/60R17, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.3 mph |
| 60 mph | 63.0 mph |
| 70 mph | 73.5 mph |
| 80 mph | 84.0 mph |
Other sizes close to 255/60R17
- 255/60R17 vs 235/60R18+0.19%
- 255/60R17 vs 225/65R17-1.83%
- 255/60R17 vs 235/65R17-0.07%
- 255/60R17 vs 225/60R17-4.88%
- 255/60R17 vs 245/65R17+1.69%
- 255/60R17 vs 255/55R18-0.01%
- 255/60R17 vs 225/75R16+0.83%
- 255/60R17 vs 235/70R16-0.33%
- 255/60R17 vs 235/60R17-3.25%
- 255/60R17 vs 215/65R17-3.59%
- 255/60R17 vs 255/65R17+3.46%
- 255/60R17 vs 235/70R17+3.12%
Questions
Can I replace 255/60R17 with 245/70R17?
245/70R17 is outside the ±3% rule as a replacement for 255/60R17: the diameter differs by +5.01%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 255/60R17 and 245/70R17?
245/70R17 is 1.46" taller and 10 mm narrower; the sidewall is +0.73". At an indicated 60 mph you'd actually be doing 63.0 mph.
Will 245/70R17 fit on 255/60R17 wheels?
Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 245 mm tire and the fender clearance.