TireSizesFinder

285/65R17 vs 285/60R18

285/60R18 is 0.12 in (3.1 mm) shorter than 285/65R17, a −0.39% diameter difference. With the speedometer set for 285/65R17, an indicated 60 mph is 59.8 mph on 285/60R18.

Is this a safe swap?

Diameter difference −0.39%: under 1%

By overall diameter alone, 285/60R18 is a near match for 285/65R17; 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: 285/65R17 (31.59 in) vs 285/60R18 (31.46 in)285/65R1731.59 in × 11.22 in285/60R1831.46 in × 11.22 in
Side profile and tread width, drawn to the same scale.
285/65R17 vs 285/60R18 differences
Measurement285/65R17285/60R18Difference% diff
Overall diameter31.59 in (802.3 mm)31.46 in (799.2 mm)−0.12 in (−3.1 mm)−0.39%
Sidewall height7.29 in (185.3 mm)6.73 in (171.0 mm)−0.56 in (−14.2 mm)−7.69%
Section width11.22 in (285.0 mm)11.22 in (285.0 mm)0.00 in (0.0 mm)0.00%
Circumference99.23 in (2,520.5 mm)98.85 in (2,510.8 mm)−0.38 in (−9.7 mm)−0.39%
Revolutions per mile639641+2+0.39%
True speed with the speedometer calibrated for 285/65R17
IndicatedActual on 285/65R17Actual on 285/60R18Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.7 mph−0.3 mph

Ride-height change: 285/60R18 lowers the vehicle by 0.06 in (1.5 mm) at the axle (half the −3.1 mm diameter difference).

285/60R18 is 0.12 in shorter than 285/65R17 and the same width, a 0.39% difference in overall diameter.

With the speedometer calibrated for 285/65R17, an indicated 60 mph is actually 59.8 mph on 285/60R18, and revolutions per mile change from 639 to 641.

285/60R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 285/65R17.

Size pages

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