265/50R21 vs 285/40R22

285/40R22 is 0.46 in (11.6 mm) shorter than 265/50R21, a −1.45% diameter difference. With the speedometer set for 265/50R21, an indicated 60 mph is 59.1 mph on 285/40R22.

Is this a safe swap?

Diameter difference −1.45%: within the ±3% guideline

By overall diameter alone, 285/40R22 falls inside the ±3% range commonly used as a guideline when replacing 265/50R21. 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.

265/50R21 vs 285/40R22 differences
Measurement	265/50R21	285/40R22	Difference	% diff
Overall diameter	31.43 in (798.4 mm)	30.98 in (786.8 mm)	−0.46 in (−11.6 mm)	−1.45%
Sidewall height	5.22 in (132.5 mm)	4.49 in (114.0 mm)	−0.73 in (−18.5 mm)	−13.96%
Section width	10.43 in (265.0 mm)	11.22 in (285.0 mm)	+0.79 in (+20.0 mm)	+7.55%
Circumference	98.75 in (2,508.2 mm)	97.32 in (2,471.8 mm)	−1.43 in (−36.4 mm)	−1.45%
Revolutions per mile	642	651	+9	+1.47%

True speed with the speedometer calibrated for 265/50R21
Indicated	Actual on 265/50R21	Actual on 285/40R22	Difference
30 mph	30.0 mph	29.6 mph	−0.4 mph
60 mph	60.0 mph	59.1 mph	−0.9 mph
75 mph	75.0 mph	73.9 mph	−1.1 mph

Ride-height change: 285/40R22 lowers the vehicle by 0.23 in (5.8 mm) at the axle (half the −11.6 mm diameter difference).

285/40R22 is 0.46 in shorter than 265/50R21 and 20 mm wider, a 1.45% difference in overall diameter.

With the speedometer calibrated for 265/50R21, an indicated 60 mph is actually 59.1 mph on 285/40R22, and revolutions per mile change from 642 to 651.

285/40R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 265/50R21.

Size pages

Other comparisons with 265/50R21

Other comparisons with 285/40R22

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