285/65R18 vs 325/60R18
325/60R18 is a safe swap for 285/65R18 by the usual ±3% rule: the diameter differs by +2.36%.
Speedometer and odometer
With 325/60R18 on a car calibrated for 285/65R18, the speedometer reads 58.6 mph when you're really doing 60, and the odometer under-counts by 2.4%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.7 mph |
| 45 mph | 46.1 mph |
| 60 mph | 61.4 mph |
| 70 mph | 71.6 mph |
| 80 mph | 81.9 mph |
Other sizes close to 285/65R18
- 285/65R18 vs 275/65R18-1.57%
- 285/65R18 vs 275/70R18+1.75%
- 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%
Questions
Can I replace 285/65R18 with 325/60R18?
325/60R18 is a safe swap for 285/65R18 by the usual ±3% rule: the diameter differs by +2.36%.
What's the difference between 285/65R18 and 325/60R18?
325/60R18 is 0.77" taller and 40 mm wider; the sidewall is +0.38". At an indicated 60 mph you'd actually be doing 61.4 mph.
Will 325/60R18 fit on 285/65R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 325 mm tire and the fender clearance.