285/45R22 vs 305/30R24

305/30R24 is 0.89 in (22.7 mm) shorter than 285/45R22, a −2.78% diameter difference. With the speedometer set for 285/45R22, an indicated 60 mph is 58.3 mph on 305/30R24.

Is this a safe swap?

Diameter difference −2.78%: within the ±3% guideline

By overall diameter alone, 305/30R24 falls inside the ±3% range commonly used as a guideline when replacing 285/45R22. 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 305/30R24 differences
Measurement	285/45R22	305/30R24	Difference	% diff
Overall diameter	32.10 in (815.3 mm)	31.20 in (792.6 mm)	−0.89 in (−22.7 mm)	−2.78%
Sidewall height	5.05 in (128.3 mm)	3.60 in (91.5 mm)	−1.45 in (−36.7 mm)	−28.65%
Section width	11.22 in (285.0 mm)	12.01 in (305.0 mm)	+0.79 in (+20.0 mm)	+7.02%
Circumference	100.84 in (2,561.3 mm)	98.03 in (2,490.0 mm)	−2.81 in (−71.3 mm)	−2.78%
Revolutions per mile	628	646	+18	+2.86%

True speed with the speedometer calibrated for 285/45R22
Indicated	Actual on 285/45R22	Actual on 305/30R24	Difference
30 mph	30.0 mph	29.2 mph	−0.8 mph
60 mph	60.0 mph	58.3 mph	−1.7 mph
75 mph	75.0 mph	72.9 mph	−2.1 mph

Ride-height change: 305/30R24 lowers the vehicle by 0.45 in (11.4 mm) at the axle (half the −22.7 mm diameter difference).

305/30R24 is 0.89 in shorter than 285/45R22 and 20 mm wider, a 2.78% difference in overall diameter.

With the speedometer calibrated for 285/45R22, an indicated 60 mph is actually 58.3 mph on 305/30R24, and revolutions per mile change from 628 to 646.

305/30R24 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 305/30R24

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