245/70R17 vs 255/75R17
255/75R17 is outside the ±3% rule as a replacement for 245/70R17: the diameter differs by +5.10%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 255/75R17 on a car calibrated for 245/70R17, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.3 mph |
| 60 mph | 63.1 mph |
| 70 mph | 73.6 mph |
| 80 mph | 84.1 mph |
Other sizes close to 245/70R17
- 245/70R17 vs 265/70R17+3.61%
- 245/70R17 vs 235/65R17-4.84%
- 245/70R17 vs 265/60R18+0.05%
- 245/70R17 vs 245/65R17-3.16%
- 245/70R17 vs 245/75R16-0.12%
- 245/70R17 vs 245/75R17+3.16%
- 245/70R17 vs 265/65R17+0.19%
- 245/70R17 vs 265/70R16+0.34%
- 245/70R17 vs 235/80R17+4.26%
- 245/70R17 vs 255/65R17-1.48%
- 245/70R17 vs 215/85R16-0.37%
- 245/70R17 vs 255/70R17+1.81%
Questions
Can I replace 245/70R17 with 255/75R17?
255/75R17 is outside the ±3% rule as a replacement for 245/70R17: the diameter differs by +5.10%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 245/70R17 and 255/75R17?
255/75R17 is 1.56" taller and 10 mm wider; the sidewall is +0.78". At an indicated 60 mph you'd actually be doing 63.1 mph.
Will 255/75R17 fit on 245/70R17 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.