285/45R22 vs 285/30R24

285/30R24 is 1.37 in (34.7 mm) shorter than 285/45R22, a −4.26% diameter difference. With the speedometer set for 285/45R22, an indicated 60 mph is 57.4 mph on 285/30R24.

Is this a safe swap?

Diameter difference −4.26%: outside the ±3% guideline

By overall diameter alone, 285/30R24 falls outside the ±3% range commonly used as a guideline when replacing 285/45R22; speedometer and ride-height changes are larger. 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.

285/45R22 vs 285/30R24 differences
Measurement	285/45R22	285/30R24	Difference	% diff
Overall diameter	32.10 in (815.3 mm)	30.73 in (780.6 mm)	−1.37 in (−34.7 mm)	−4.26%
Sidewall height	5.05 in (128.3 mm)	3.37 in (85.5 mm)	−1.68 in (−42.7 mm)	−33.33%
Section width	11.22 in (285.0 mm)	11.22 in (285.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	100.84 in (2,561.3 mm)	96.55 in (2,452.3 mm)	−4.29 in (−109.0 mm)	−4.26%
Revolutions per mile	628	656	+28	+4.45%

True speed with the speedometer calibrated for 285/45R22
Indicated	Actual on 285/45R22	Actual on 285/30R24	Difference
30 mph	30.0 mph	28.7 mph	−1.3 mph
60 mph	60.0 mph	57.4 mph	−2.6 mph
75 mph	75.0 mph	71.8 mph	−3.2 mph

Ride-height change: 285/30R24 lowers the vehicle by 0.68 in (17.4 mm) at the axle (half the −34.7 mm diameter difference).

285/30R24 is 1.37 in shorter than 285/45R22 and the same width, a 4.26% difference in overall diameter.

With the speedometer calibrated for 285/45R22, an indicated 60 mph is actually 57.4 mph on 285/30R24, and revolutions per mile change from 628 to 656.

285/30R24 mounts on a 24-inch wheel, a plus-2 fitment from the 22-inch wheel of 285/45R22.

Size pages

Other comparisons with 285/45R22

Other comparisons with 285/30R24

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