325/45R22 vs 305/35R24

305/35R24 is 1.11 in (28.2 mm) shorter than 325/45R22, a −3.31% diameter difference. With the speedometer set for 325/45R22, an indicated 60 mph is 58.0 mph on 305/35R24.

Is this a safe swap?

Diameter difference −3.31%: outside the ±3% guideline

By overall diameter alone, 305/35R24 falls outside the ±3% range commonly used as a guideline when replacing 325/45R22; 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.

325/45R22 vs 305/35R24 differences
Measurement	325/45R22	305/35R24	Difference	% diff
Overall diameter	33.52 in (851.3 mm)	32.41 in (823.1 mm)	−1.11 in (−28.2 mm)	−3.31%
Sidewall height	5.76 in (146.3 mm)	4.20 in (106.8 mm)	−1.56 in (−39.5 mm)	−27.01%
Section width	12.80 in (325.0 mm)	12.01 in (305.0 mm)	−0.79 in (−20.0 mm)	−6.15%
Circumference	105.29 in (2,674.4 mm)	101.80 in (2,585.8 mm)	−3.49 in (−88.6 mm)	−3.31%
Revolutions per mile	602	622	+21	+3.43%

True speed with the speedometer calibrated for 325/45R22
Indicated	Actual on 325/45R22	Actual on 305/35R24	Difference
30 mph	30.0 mph	29.0 mph	−1.0 mph
60 mph	60.0 mph	58.0 mph	−2.0 mph
75 mph	75.0 mph	72.5 mph	−2.5 mph

Ride-height change: 305/35R24 lowers the vehicle by 0.56 in (14.1 mm) at the axle (half the −28.2 mm diameter difference).

305/35R24 is 1.11 in shorter than 325/45R22 and 20 mm narrower, a 3.31% difference in overall diameter.

With the speedometer calibrated for 325/45R22, an indicated 60 mph is actually 58.0 mph on 305/35R24, and revolutions per mile change from 602 to 622.

305/35R24 mounts on a 24-inch wheel, a plus-2 fitment from the 22-inch wheel of 325/45R22.

Size pages

Other comparisons with 325/45R22

Other comparisons with 305/35R24

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