TireSizesFinder

33x12.50R15 vs 285/70R17

285/70R17 is 0.29 in (7.4 mm) shorter than 33x12.50R15, a −0.88% diameter difference. With the speedometer set for 33x12.50R15, an indicated 60 mph is 59.5 mph on 285/70R17.

Is this a safe swap?

Diameter difference −0.88%: under 1%

By overall diameter alone, 285/70R17 is a near match for 33x12.50R15; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 33x12.50R15 (33.00 in) vs 285/70R17 (32.71 in)33x12.50R1533.00 in × 12.50 in285/70R1732.71 in × 11.22 in
Side profile and tread width, drawn to the same scale.
33x12.50R15 vs 285/70R17 differences
Measurement33x12.50R15285/70R17Difference% diff
Overall diameter33.00 in (838.2 mm)32.71 in (830.8 mm)−0.29 in (−7.4 mm)−0.88%
Sidewall height9.00 in (228.6 mm)7.85 in (199.5 mm)−1.15 in (−29.1 mm)−12.73%
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)102.76 in (2,610.0 mm)−0.92 in (−23.2 mm)−0.88%
Revolutions per mile611617+5+0.89%
True speed with the speedometer calibrated for 33x12.50R15
IndicatedActual on 33x12.50R15Actual on 285/70R17Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.5 mph−0.5 mph
75 mph75.0 mph74.3 mph−0.7 mph

Ride-height change: 285/70R17 lowers the vehicle by 0.15 in (3.7 mm) at the axle (half the −7.4 mm diameter difference).

285/70R17 is 0.29 in shorter than 33x12.50R15 and 33 mm narrower, a 0.88% difference in overall diameter.

With the speedometer calibrated for 33x12.50R15, an indicated 60 mph is actually 59.5 mph on 285/70R17, and revolutions per mile change from 611 to 617.

285/70R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 33x12.50R15.

Size pages

Other comparisons with 33x12.50R15

Other comparisons with 285/70R17

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