33x12.50R18 vs 325/60R18
325/60R18 is a safe swap for 33x12.50R18 by the usual ±3% rule: the diameter differs by +1.07%.
Side by side
| 33x12.50R18 | 325/60R18 | Difference | |
|---|---|---|---|
| Overall diameter | 33.00" | 33.35" | +0.35" (+1.07%) |
| Section width | 318 mm | 325 mm | +7 mm |
| Sidewall | 7.50" | 7.68" | +0.18" |
| Rim | 18" | 18" | same |
| Circumference | 103.7" | 104.8" | +1.1" |
| Revs per mile | 611 | 605 | -6 |
| Ride height | — | — | +0.18" |
| Speedometer reads 60 mph | 60.0 | 60.6 | +0.6 mph |
Speedometer and odometer
With 325/60R18 on a car calibrated for 33x12.50R18, the speedometer reads 59.4 mph when you're really doing 60, and the odometer under-counts by 1.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.3 mph |
| 45 mph | 45.5 mph |
| 60 mph | 60.6 mph |
| 70 mph | 70.8 mph |
| 80 mph | 80.9 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 325/60R18?
325/60R18 is a safe swap for 33x12.50R18 by the usual ±3% rule: the diameter differs by +1.07%.
What's the difference between 33x12.50R18 and 325/60R18?
325/60R18 is 0.35" taller and 7 mm wider; the sidewall is +0.18". At an indicated 60 mph you'd actually be doing 60.6 mph.
Will 325/60R18 fit on 33x12.50R18 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.