285/70R18 vs 35x12.50R18
35x12.50R18 is outside the ±3% rule as a replacement for 285/70R18: the diameter differs by +3.83%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Side by side
| 285/70R18 | 35x12.50R18 | Difference | |
|---|---|---|---|
| Overall diameter | 33.71" | 35.00" | +1.29" (+3.83%) |
| Section width | 285 mm | 318 mm | +33 mm |
| Sidewall | 7.85" | 8.50" | +0.65" |
| Rim | 18" | 18" | same |
| Circumference | 105.9" | 110.0" | +4.1" |
| Revs per mile | 598 | 576 | -22 |
| Ride height | — | — | +0.65" |
| Speedometer reads 60 mph | 60.0 | 62.3 | +2.3 mph |
Speedometer and odometer
With 35x12.50R18 on a car calibrated for 285/70R18, the speedometer reads 57.8 mph when you're really doing 60, and the odometer under-counts by 3.8%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.1 mph |
| 45 mph | 46.7 mph |
| 60 mph | 62.3 mph |
| 70 mph | 72.7 mph |
| 80 mph | 83.1 mph |
Other sizes close to 285/70R18
- 285/70R18 vs 275/65R18-4.85%
- 285/70R18 vs 275/70R18-1.64%
- 285/70R18 vs 265/70R18-3.27%
- 285/70R18 vs 255/70R18-4.91%
- 285/70R18 vs 285/65R18-3.33%
- 285/70R18 vs 295/70R18+1.64%
- 285/70R18 vs 33x12.50R18-2.10%
- 285/70R18 vs 285/75R17+0.36%
- 285/70R18 vs 285/75R18+3.33%
- 285/70R18 vs 325/65R18+2.74%
- 285/70R18 vs 305/70R18+3.27%
- 285/70R18 vs 305/65R18-0.29%
Questions
Can I replace 285/70R18 with 35x12.50R18?
35x12.50R18 is outside the ±3% rule as a replacement for 285/70R18: the diameter differs by +3.83%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 285/70R18 and 35x12.50R18?
35x12.50R18 is 1.29" taller and 33 mm wider; the sidewall is +0.65". At an indicated 60 mph you'd actually be doing 62.3 mph.
Will 35x12.50R18 fit on 285/70R18 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.