TireSizesFinder

285/75R16 vs 285/65R18

285/65R18 is 0.24 in (6.2 mm) shorter than 285/75R16, a −0.74% diameter difference. With the speedometer set for 285/75R16, an indicated 60 mph is 59.6 mph on 285/65R18.

Is this a safe swap?

Diameter difference −0.74%: under 1%

By overall diameter alone, 285/65R18 is a near match for 285/75R16; 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: 285/75R16 (32.83 in) vs 285/65R18 (32.59 in)285/75R1632.83 in × 11.22 in285/65R1832.59 in × 11.22 in
Side profile and tread width, drawn to the same scale.
285/75R16 vs 285/65R18 differences
Measurement285/75R16285/65R18Difference% diff
Overall diameter32.83 in (833.9 mm)32.59 in (827.7 mm)−0.24 in (−6.2 mm)−0.74%
Sidewall height8.42 in (213.8 mm)7.29 in (185.3 mm)−1.12 in (−28.5 mm)−13.33%
Section width11.22 in (285.0 mm)11.22 in (285.0 mm)0.00 in (0.0 mm)0.00%
Circumference103.14 in (2,619.8 mm)102.37 in (2,600.3 mm)−0.77 in (−19.5 mm)−0.74%
Revolutions per mile614619+5+0.75%
True speed with the speedometer calibrated for 285/75R16
IndicatedActual on 285/75R16Actual on 285/65R18Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.4 mph−0.6 mph

Ride-height change: 285/65R18 lowers the vehicle by 0.12 in (3.1 mm) at the axle (half the −6.2 mm diameter difference).

285/65R18 is 0.24 in shorter than 285/75R16 and the same width, a 0.74% difference in overall diameter.

With the speedometer calibrated for 285/75R16, an indicated 60 mph is actually 59.6 mph on 285/65R18, and revolutions per mile change from 614 to 619.

285/65R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 285/75R16.

Size pages

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