285/75R18 vs 295/60R20

295/60R20 is 0.89 in (22.7 mm) shorter than 285/75R18, a −2.57% diameter difference. With the speedometer set for 285/75R18, an indicated 60 mph is 58.5 mph on 295/60R20.

Is this a safe swap?

Diameter difference −2.57%: within the ±3% guideline

By overall diameter alone, 295/60R20 falls inside the ±3% range commonly used as a guideline when replacing 285/75R18. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

285/75R18 vs 295/60R20 differences
Measurement	285/75R18	295/60R20	Difference	% diff
Overall diameter	34.83 in (884.7 mm)	33.94 in (862.0 mm)	−0.89 in (−22.7 mm)	−2.57%
Sidewall height	8.42 in (213.8 mm)	6.97 in (177.0 mm)	−1.45 in (−36.7 mm)	−17.19%
Section width	11.22 in (285.0 mm)	11.61 in (295.0 mm)	+0.39 in (+10.0 mm)	+3.51%
Circumference	109.42 in (2,779.4 mm)	106.62 in (2,708.1 mm)	−2.81 in (−71.3 mm)	−2.57%
Revolutions per mile	579	594	+15	+2.63%

True speed with the speedometer calibrated for 285/75R18
Indicated	Actual on 285/75R18	Actual on 295/60R20	Difference
30 mph	30.0 mph	29.2 mph	−0.8 mph
60 mph	60.0 mph	58.5 mph	−1.5 mph
75 mph	75.0 mph	73.1 mph	−1.9 mph

Ride-height change: 295/60R20 lowers the vehicle by 0.45 in (11.4 mm) at the axle (half the −22.7 mm diameter difference).

295/60R20 is 0.89 in shorter than 285/75R18 and 10 mm wider, a 2.57% difference in overall diameter.

With the speedometer calibrated for 285/75R18, an indicated 60 mph is actually 58.5 mph on 295/60R20, and revolutions per mile change from 579 to 594.

295/60R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 285/75R18.

Size pages

Other comparisons with 285/75R18

Other comparisons with 295/60R20

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.