255/65R17 vs 245/70R17
245/70R17 is a safe swap for 255/65R17 by the usual ±3% rule: the diameter differs by +1.51%.
Speedometer and odometer
With 245/70R17 on a car calibrated for 255/65R17, the speedometer reads 59.1 mph when you're really doing 60, and the odometer under-counts by 1.5%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.5 mph |
| 45 mph | 45.7 mph |
| 60 mph | 60.9 mph |
| 70 mph | 71.1 mph |
| 80 mph | 81.2 mph |
Other sizes close to 255/65R17
- 255/65R17 vs 235/65R17-3.41%
- 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 255/70R17+3.34%
- 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 245/70R17?
245/70R17 is a safe swap for 255/65R17 by the usual ±3% rule: the diameter differs by +1.51%.
What's the difference between 255/65R17 and 245/70R17?
245/70R17 is 0.45" taller and 10 mm narrower; the sidewall is +0.23". At an indicated 60 mph you'd actually be doing 60.9 mph.
Will 245/70R17 fit on 255/65R17 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.