TireSizesFinder

205/75R16 vs 285/45R18

285/45R18 is 0.01 in (0.2 mm) shorter than 205/75R16, a −0.03% diameter difference. With the speedometer set for 205/75R16, an indicated 60 mph is 60.0 mph on 285/45R18.

Is this a safe swap?

Diameter difference −0.03%: under 1%

By overall diameter alone, 285/45R18 is a near match for 205/75R16; 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: 205/75R16 (28.11 in) vs 285/45R18 (28.10 in)205/75R1628.11 in × 8.07 in285/45R1828.10 in × 11.22 in
Side profile and tread width, drawn to the same scale.
205/75R16 vs 285/45R18 differences
Measurement205/75R16285/45R18Difference% diff
Overall diameter28.11 in (713.9 mm)28.10 in (713.7 mm)−0.01 in (−0.2 mm)−0.03%
Sidewall height6.05 in (153.8 mm)5.05 in (128.3 mm)−1.00 in (−25.5 mm)−16.59%
Section width8.07 in (205.0 mm)11.22 in (285.0 mm)+3.15 in (+80.0 mm)+39.02%
Circumference88.30 in (2,242.8 mm)88.27 in (2,242.2 mm)−0.02 in (−0.6 mm)−0.03%
Revolutions per mile7187180+0.03%
True speed with the speedometer calibrated for 205/75R16
IndicatedActual on 205/75R16Actual on 285/45R18Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph60.0 mph0.0 mph
75 mph75.0 mph75.0 mph0.0 mph

Ride-height change: 285/45R18 lowers the vehicle by 0.00 in (0.1 mm) at the axle (half the −0.2 mm diameter difference).

285/45R18 is 0.01 in shorter than 205/75R16 and 80 mm wider, a 0.03% difference in overall diameter.

With the speedometer calibrated for 205/75R16, an indicated 60 mph is actually 60.0 mph on 285/45R18, and revolutions per mile change from 718 to 718.

285/45R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 205/75R16.

Size pages

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