255/70R17 vs 245/75R17
245/75R17 is a safe swap for 255/70R17 by the usual ±3% rule: the diameter differs by +1.33%.
Speedometer and odometer
With 245/75R17 on a car calibrated for 255/70R17, the speedometer reads 59.2 mph when you're really doing 60, and the odometer under-counts by 1.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.4 mph |
| 45 mph | 45.6 mph |
| 60 mph | 60.8 mph |
| 70 mph | 70.9 mph |
| 80 mph | 81.1 mph |
Other sizes close to 255/70R17
- 255/70R17 vs 265/70R17+1.77%
- 255/70R17 vs 245/70R17-1.77%
- 255/70R17 vs 245/65R17-4.88%
- 255/70R17 vs 265/65R17-1.58%
- 255/70R17 vs 235/80R17+2.41%
- 255/70R17 vs 255/65R18-0.01%
- 255/70R17 vs 255/65R17-3.23%
- 255/70R17 vs 255/75R17+3.23%
- 255/70R17 vs 235/75R17-0.57%
- 255/70R17 vs 275/70R17+3.55%
- 255/70R17 vs 235/70R17-3.55%
- 255/70R17 vs 275/60R18-0.20%
Questions
Can I replace 255/70R17 with 245/75R17?
245/75R17 is a safe swap for 255/70R17 by the usual ±3% rule: the diameter differs by +1.33%.
What's the difference between 255/70R17 and 245/75R17?
245/75R17 is 0.41" taller and 10 mm narrower; the sidewall is +0.21". At an indicated 60 mph you'd actually be doing 60.8 mph.
Will 245/75R17 fit on 255/70R17 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.