325/60R18 vs 35x12.50R18
35x12.50R18 is outside the ±3% rule as a replacement for 325/60R18: the diameter differs by +4.93%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Side by side
| 325/60R18 | 35x12.50R18 | Difference | |
|---|---|---|---|
| Overall diameter | 33.35" | 35.00" | +1.65" (+4.93%) |
| Section width | 325 mm | 318 mm | -7 mm |
| Sidewall | 7.68" | 8.50" | +0.82" |
| Rim | 18" | 18" | same |
| Circumference | 104.8" | 110.0" | +5.2" |
| Revs per mile | 605 | 576 | -28 |
| Ride height | — | — | +0.82" |
| Speedometer reads 60 mph | 60.0 | 63.0 | +3.0 mph |
Speedometer and odometer
With 35x12.50R18 on a car calibrated for 325/60R18, the speedometer reads 57.2 mph when you're really doing 60, and the odometer under-counts by 4.9%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.2 mph |
| 60 mph | 63.0 mph |
| 70 mph | 73.5 mph |
| 80 mph | 83.9 mph |
Other sizes close to 325/60R18
- 325/60R18 vs 275/65R18-3.84%
- 325/60R18 vs 275/70R18-0.59%
- 325/60R18 vs 265/70R18-2.24%
- 325/60R18 vs 255/70R18-3.90%
- 325/60R18 vs 285/65R18-2.30%
- 325/60R18 vs 295/70R18+2.71%
- 325/60R18 vs 295/70R17-0.28%
- 325/60R18 vs 33x12.50R18-1.06%
- 325/60R18 vs 285/75R18+4.43%
- 325/60R18 vs 325/65R18+3.84%
- 325/60R18 vs 305/70R18+4.37%
- 325/60R18 vs 255/80R17-0.87%
Questions
Can I replace 325/60R18 with 35x12.50R18?
35x12.50R18 is outside the ±3% rule as a replacement for 325/60R18: the diameter differs by +4.93%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 325/60R18 and 35x12.50R18?
35x12.50R18 is 1.65" taller and 7 mm narrower; the sidewall is +0.82". At an indicated 60 mph you'd actually be doing 63.0 mph.
Will 35x12.50R18 fit on 325/60R18 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.