285/60R20 vs 35x12.50R20
35x12.50R20 is outside the ±3% rule as a replacement for 285/60R20: the diameter differs by +4.59%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Side by side
| 285/60R20 | 35x12.50R20 | Difference | |
|---|---|---|---|
| Overall diameter | 33.46" | 35.00" | +1.54" (+4.59%) |
| Section width | 285 mm | 318 mm | +33 mm |
| Sidewall | 6.73" | 7.50" | +0.77" |
| Rim | 20" | 20" | same |
| Circumference | 105.1" | 110.0" | +4.8" |
| Revs per mile | 603 | 576 | -26 |
| Ride height | — | — | +0.77" |
| Speedometer reads 60 mph | 60.0 | 62.8 | +2.8 mph |
Speedometer and odometer
With 35x12.50R20 on a car calibrated for 285/60R20, the speedometer reads 57.4 mph when you're really doing 60, and the odometer under-counts by 4.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.4 mph |
| 45 mph | 47.1 mph |
| 60 mph | 62.8 mph |
| 70 mph | 73.2 mph |
| 80 mph | 83.7 mph |
Other sizes close to 285/60R20
- 285/60R20 vs 275/55R20-4.65%
- 285/60R20 vs 275/60R20-1.41%
- 285/60R20 vs 275/65R20+1.82%
- 285/60R20 vs 265/60R20-2.82%
- 285/60R20 vs 305/55R20-0.76%
- 285/60R20 vs 285/55R20-3.35%
- 285/60R20 vs 33x12.50R20-1.39%
- 285/60R20 vs 295/60R20+1.41%
- 285/60R20 vs 295/55R20-2.06%
- 285/60R20 vs 295/65R20+4.88%
- 285/60R20 vs 285/65R20+3.35%
- 285/60R20 vs 305/50R20-4.35%
Questions
Can I replace 285/60R20 with 35x12.50R20?
35x12.50R20 is outside the ±3% rule as a replacement for 285/60R20: the diameter differs by +4.59%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 285/60R20 and 35x12.50R20?
35x12.50R20 is 1.54" taller and 33 mm wider; the sidewall is +0.77". At an indicated 60 mph you'd actually be doing 62.8 mph.
Will 35x12.50R20 fit on 285/60R20 wheels?
Both use a 20" rim, so the wheel diameter matches; check the wheel's width range for a 318 mm tire and the fender clearance.