33x12.50R18 vs 285/70R18
285/70R18 is a safe swap for 33x12.50R18 by the usual ±3% rule: the diameter differs by +2.15%.
Side by side
| 33x12.50R18 | 285/70R18 | Difference | |
|---|---|---|---|
| Overall diameter | 33.00" | 33.71" | +0.71" (+2.15%) |
| Section width | 318 mm | 285 mm | -33 mm |
| Sidewall | 7.50" | 7.85" | +0.35" |
| Rim | 18" | 18" | same |
| Circumference | 103.7" | 105.9" | +2.2" |
| Revs per mile | 611 | 598 | -13 |
| Ride height | — | — | +0.35" |
| Speedometer reads 60 mph | 60.0 | 61.3 | +1.3 mph |
Speedometer and odometer
With 285/70R18 on a car calibrated for 33x12.50R18, the speedometer reads 58.7 mph when you're really doing 60, and the odometer under-counts by 2.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.6 mph |
| 45 mph | 46.0 mph |
| 60 mph | 61.3 mph |
| 70 mph | 71.5 mph |
| 80 mph | 81.7 mph |
Other sizes close to 33x12.50R18
- 33x12.50R18 vs 275/65R18-2.80%
- 33x12.50R18 vs 275/70R18+0.48%
- 33x12.50R18 vs 285/70R17-0.88%
- 33x12.50R18 vs 265/65R18-4.35%
- 33x12.50R18 vs 265/70R18-1.19%
- 33x12.50R18 vs 255/70R18-2.86%
- 33x12.50R18 vs 285/65R18-1.25%
- 33x12.50R18 vs 295/70R18+3.82%
- 33x12.50R18 vs 295/70R17+0.79%
- 33x12.50R18 vs 285/60R18-4.65%
- 33x12.50R18 vs 33x12.50R170.00%
- 33x12.50R18 vs 325/65R18+4.95%
Questions
Can I replace 33x12.50R18 with 285/70R18?
285/70R18 is a safe swap for 33x12.50R18 by the usual ±3% rule: the diameter differs by +2.15%.
What's the difference between 33x12.50R18 and 285/70R18?
285/70R18 is 0.71" taller and 33 mm narrower; the sidewall is +0.35". At an indicated 60 mph you'd actually be doing 61.3 mph.
Will 285/70R18 fit on 33x12.50R18 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.