255/65R18 vs 255/70R17
255/70R17 is a safe swap for 255/65R18 by the usual ±3% rule: the diameter differs by +0.01%.
Speedometer and odometer
With 255/70R17 on a car calibrated for 255/65R18, the speedometer reads 60.0 mph when you're really doing 60, and the odometer under-counts by 0.0%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.0 mph |
| 45 mph | 45.0 mph |
| 60 mph | 60.0 mph |
| 70 mph | 70.0 mph |
| 80 mph | 80.0 mph |
Other sizes close to 255/65R18
- 255/65R18 vs 275/65R18+3.30%
- 255/65R18 vs 265/60R18-1.71%
- 255/65R18 vs 245/60R18-4.75%
- 255/65R18 vs 265/65R18+1.65%
- 255/65R18 vs 235/65R18-3.30%
- 255/65R18 vs 255/70R18+3.23%
- 255/65R18 vs 255/60R19-0.01%
- 255/65R18 vs 285/65R18+4.94%
- 255/65R18 vs 255/60R18-3.23%
- 255/65R18 vs 235/75R17-0.56%
- 255/65R18 vs 285/60R18+1.33%
- 255/65R18 vs 275/55R19-0.46%
Questions
Can I replace 255/65R18 with 255/70R17?
255/70R17 is a safe swap for 255/65R18 by the usual ±3% rule: the diameter differs by +0.01%.
What's the difference between 255/65R18 and 255/70R17?
255/70R17 is 0.00" taller and 0 mm wider; the sidewall is +0.50". At an indicated 60 mph you'd actually be doing 60.0 mph.
Will 255/70R17 fit on 255/65R18 wheels?
No — 255/65R18 needs a 18" wheel and 255/70R17 a 17" wheel. This is a plus/minus-size swap that changes wheels too.