TireSizesFinder

235/85R16 vs 285/65R17

285/65R17 is 0.14 in (3.6 mm) shorter than 235/85R16, a −0.45% diameter difference. With the speedometer set for 235/85R16, an indicated 60 mph is 59.7 mph on 285/65R17.

Is this a safe swap?

Diameter difference −0.45%: under 1%

By overall diameter alone, 285/65R17 is a near match for 235/85R16; 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: 235/85R16 (31.73 in) vs 285/65R17 (31.59 in)235/85R1631.73 in × 9.25 in285/65R1731.59 in × 11.22 in
Side profile and tread width, drawn to the same scale.
235/85R16 vs 285/65R17 differences
Measurement235/85R16285/65R17Difference% diff
Overall diameter31.73 in (805.9 mm)31.59 in (802.3 mm)−0.14 in (−3.6 mm)−0.45%
Sidewall height7.86 in (199.8 mm)7.29 in (185.3 mm)−0.57 in (−14.5 mm)−7.26%
Section width9.25 in (235.0 mm)11.22 in (285.0 mm)+1.97 in (+50.0 mm)+21.28%
Circumference99.68 in (2,531.8 mm)99.23 in (2,520.5 mm)−0.45 in (−11.3 mm)−0.45%
Revolutions per mile636639+3+0.45%
True speed with the speedometer calibrated for 235/85R16
IndicatedActual on 235/85R16Actual on 285/65R17Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.7 mph−0.3 mph
75 mph75.0 mph74.7 mph−0.3 mph

Ride-height change: 285/65R17 lowers the vehicle by 0.07 in (1.8 mm) at the axle (half the −3.6 mm diameter difference).

285/65R17 is 0.14 in shorter than 235/85R16 and 50 mm wider, a 0.45% difference in overall diameter.

With the speedometer calibrated for 235/85R16, an indicated 60 mph is actually 59.7 mph on 285/65R17, and revolutions per mile change from 636 to 639.

285/65R17 mounts on a 17-inch wheel, a plus-1 fitment from the 16-inch wheel of 235/85R16.

Size pages

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