TireSizesFinder

33x12.50R20 vs 285/60R20

285/60R20 is 0.46 in (11.8 mm) taller than 33x12.50R20, a +1.41% diameter difference. With the speedometer set for 33x12.50R20, an indicated 60 mph is 60.8 mph on 285/60R20.

Is this a safe swap?

Diameter difference +1.41%: within the ±3% guideline

By overall diameter alone, 285/60R20 falls inside the ±3% range commonly used as a guideline when replacing 33x12.50R20. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 33x12.50R20 (33.00 in) vs 285/60R20 (33.46 in)33x12.50R2033.00 in × 12.50 in285/60R2033.46 in × 11.22 in
Side profile and tread width, drawn to the same scale.
33x12.50R20 vs 285/60R20 differences
Measurement33x12.50R20285/60R20Difference% diff
Overall diameter33.00 in (838.2 mm)33.46 in (850.0 mm)+0.46 in (+11.8 mm)+1.41%
Sidewall height6.50 in (165.1 mm)6.73 in (171.0 mm)+0.23 in (+5.9 mm)+3.57%
Section width12.50 in (317.5 mm)11.22 in (285.0 mm)−1.28 in (−32.5 mm)−10.24%
Circumference103.67 in (2,633.3 mm)105.13 in (2,670.4 mm)+1.46 in (+37.1 mm)+1.41%
Revolutions per mile611603−8−1.39%
True speed with the speedometer calibrated for 33x12.50R20
IndicatedActual on 33x12.50R20Actual on 285/60R20Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.8 mph+0.8 mph
75 mph75.0 mph76.1 mph+1.1 mph

Ride-height change: 285/60R20 raises the vehicle by 0.23 in (5.9 mm) at the axle (half the +11.8 mm diameter difference).

285/60R20 is 0.46 in taller than 33x12.50R20 and 33 mm narrower, a 1.41% difference in overall diameter.

With the speedometer calibrated for 33x12.50R20, an indicated 60 mph is actually 60.8 mph on 285/60R20, and revolutions per mile change from 611 to 603.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 33x12.50R20

Other comparisons with 285/60R20

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.