285/40R21 vs 285/35R22

285/35R22 is 0.12 in (3.1 mm) shorter than 285/40R21, a −0.41% diameter difference. With the speedometer set for 285/40R21, an indicated 60 mph is 59.8 mph on 285/35R22.

Is this a safe swap?

Diameter difference −0.41%: under 1%

By overall diameter alone, 285/35R22 is a near match for 285/40R21; the speedometer changes by less than 1%. 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.

285/40R21 vs 285/35R22 differences
Measurement	285/40R21	285/35R22	Difference	% diff
Overall diameter	29.98 in (761.4 mm)	29.85 in (758.3 mm)	−0.12 in (−3.1 mm)	−0.41%
Sidewall height	4.49 in (114.0 mm)	3.93 in (99.8 mm)	−0.56 in (−14.2 mm)	−12.50%
Section width	11.22 in (285.0 mm)	11.22 in (285.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	94.17 in (2,392.0 mm)	93.79 in (2,382.3 mm)	−0.38 in (−9.7 mm)	−0.41%
Revolutions per mile	673	676	+3	+0.41%

True speed with the speedometer calibrated for 285/40R21
Indicated	Actual on 285/40R21	Actual on 285/35R22	Difference
30 mph	30.0 mph	29.9 mph	−0.1 mph
60 mph	60.0 mph	59.8 mph	−0.2 mph
75 mph	75.0 mph	74.7 mph	−0.3 mph

Ride-height change: 285/35R22 lowers the vehicle by 0.06 in (1.6 mm) at the axle (half the −3.1 mm diameter difference).

285/35R22 is 0.12 in shorter than 285/40R21 and the same width, a 0.41% difference in overall diameter.

With the speedometer calibrated for 285/40R21, an indicated 60 mph is actually 59.8 mph on 285/35R22, and revolutions per mile change from 673 to 676.

285/35R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 285/40R21.

Size pages

Other comparisons with 285/40R21

Other comparisons with 285/35R22

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