285/65R18 vs 275/70R18
275/70R18 is a safe swap for 285/65R18 by the usual ±3% rule: the diameter differs by +1.75%.
Speedometer and odometer
With 275/70R18 on a car calibrated for 285/65R18, the speedometer reads 59.0 mph when you're really doing 60, and the odometer under-counts by 1.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.5 mph |
| 45 mph | 45.8 mph |
| 60 mph | 61.1 mph |
| 70 mph | 71.2 mph |
| 80 mph | 81.4 mph |
Other sizes close to 285/65R18
- 285/65R18 vs 275/65R18-1.57%
- 285/65R18 vs 285/70R17+0.37%
- 285/65R18 vs 265/65R18-3.14%
- 285/65R18 vs 265/70R18+0.06%
- 285/65R18 vs 255/70R18-1.63%
- 285/65R18 vs 255/65R18-4.71%
- 285/65R18 vs 33x12.50R18+1.27%
- 285/65R18 vs 285/60R18-3.44%
- 285/65R18 vs 305/65R18+3.14%
- 285/65R18 vs 275/60R18-4.89%
- 285/65R18 vs 305/60R18-0.54%
- 285/65R18 vs 285/70R18+3.44%
Questions
Can I replace 285/65R18 with 275/70R18?
275/70R18 is a safe swap for 285/65R18 by the usual ±3% rule: the diameter differs by +1.75%.
What's the difference between 285/65R18 and 275/70R18?
275/70R18 is 0.57" taller and 10 mm narrower; the sidewall is +0.29". At an indicated 60 mph you'd actually be doing 61.1 mph.
Will 275/70R18 fit on 285/65R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 275 mm tire and the fender clearance.