275/65R18 vs 285/65R18
285/65R18 is a safe swap for 275/65R18 by the usual ±3% rule: the diameter differs by +1.60%.
Speedometer and odometer
With 285/65R18 on a car calibrated for 275/65R18, the speedometer reads 59.1 mph when you're really doing 60, and the odometer under-counts by 1.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.5 mph |
| 45 mph | 45.7 mph |
| 60 mph | 61.0 mph |
| 70 mph | 71.1 mph |
| 80 mph | 81.3 mph |
Other sizes close to 275/65R18
- 275/65R18 vs 265/60R18-4.85%
- 275/65R18 vs 275/70R18+3.38%
- 275/65R18 vs 265/65R18-1.60%
- 275/65R18 vs 265/70R18+1.66%
- 275/65R18 vs 235/80R17-0.85%
- 275/65R18 vs 255/70R18-0.06%
- 275/65R18 vs 255/65R18-3.19%
- 275/65R18 vs 255/75R17-0.05%
- 275/65R18 vs 33x12.50R18+2.88%
- 275/65R18 vs 285/60R18-1.90%
- 275/65R18 vs 275/70R17+0.26%
- 275/65R18 vs 305/65R18+4.79%
Questions
Can I replace 275/65R18 with 285/65R18?
285/65R18 is a safe swap for 275/65R18 by the usual ±3% rule: the diameter differs by +1.60%.
What's the difference between 275/65R18 and 285/65R18?
285/65R18 is 0.51" taller and 10 mm wider; the sidewall is +0.26". At an indicated 60 mph you'd actually be doing 61.0 mph.
Will 285/65R18 fit on 275/65R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 285 mm tire and the fender clearance.