285/65R18 vs 33x12.50R18
33x12.50R18 is a safe swap for 285/65R18 by the usual ±3% rule: the diameter differs by +1.27%.
Side by side
| 285/65R18 | 33x12.50R18 | Difference | |
|---|---|---|---|
| Overall diameter | 32.59" | 33.00" | +0.41" (+1.27%) |
| Section width | 285 mm | 318 mm | +33 mm |
| Sidewall | 7.29" | 7.50" | +0.21" |
| Rim | 18" | 18" | same |
| Circumference | 102.4" | 103.7" | +1.3" |
| Revs per mile | 619 | 611 | -8 |
| Ride height | — | — | +0.21" |
| Speedometer reads 60 mph | 60.0 | 60.8 | +0.8 mph |
Speedometer and odometer
With 33x12.50R18 on a car calibrated for 285/65R18, the speedometer reads 59.2 mph when you're really doing 60, and the odometer under-counts by 1.3%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.4 mph |
| 45 mph | 45.6 mph |
| 60 mph | 60.8 mph |
| 70 mph | 70.9 mph |
| 80 mph | 81.0 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 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 33x12.50R18?
33x12.50R18 is a safe swap for 285/65R18 by the usual ±3% rule: the diameter differs by +1.27%.
What's the difference between 285/65R18 and 33x12.50R18?
33x12.50R18 is 0.41" taller and 33 mm wider; the sidewall is +0.21". At an indicated 60 mph you'd actually be doing 60.8 mph.
Will 33x12.50R18 fit on 285/65R18 wheels?
Both use a 18" rim, so the wheel diameter matches; check the wheel's width range for a 318 mm tire and the fender clearance.