305/35R22 vs 305/30R24

305/30R24 is 0.80 in (20.3 mm) taller than 305/35R22, a +2.63% diameter difference. With the speedometer set for 305/35R22, an indicated 60 mph is 61.6 mph on 305/30R24.

Is this a safe swap?

Diameter difference +2.63%: within the ±3% guideline

By overall diameter alone, 305/30R24 falls inside the ±3% range commonly used as a guideline when replacing 305/35R22. 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.

305/35R22 vs 305/30R24 differences
Measurement	305/35R22	305/30R24	Difference	% diff
Overall diameter	30.41 in (772.3 mm)	31.20 in (792.6 mm)	+0.80 in (+20.3 mm)	+2.63%
Sidewall height	4.20 in (106.8 mm)	3.60 in (91.5 mm)	−0.60 in (−15.2 mm)	−14.29%
Section width	12.01 in (305.0 mm)	12.01 in (305.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	95.52 in (2,426.3 mm)	98.03 in (2,490.0 mm)	+2.51 in (+63.8 mm)	+2.63%
Revolutions per mile	663	646	−17	−2.56%

True speed with the speedometer calibrated for 305/35R22
Indicated	Actual on 305/35R22	Actual on 305/30R24	Difference
30 mph	30.0 mph	30.8 mph	+0.8 mph
60 mph	60.0 mph	61.6 mph	+1.6 mph
75 mph	75.0 mph	77.0 mph	+2.0 mph

Ride-height change: 305/30R24 raises the vehicle by 0.40 in (10.1 mm) at the axle (half the +20.3 mm diameter difference).

305/30R24 is 0.80 in taller than 305/35R22 and the same width, a 2.63% difference in overall diameter.

With the speedometer calibrated for 305/35R22, an indicated 60 mph is actually 61.6 mph on 305/30R24, and revolutions per mile change from 663 to 646.

305/30R24 mounts on a 24-inch wheel, a plus-2 fitment from the 22-inch wheel of 305/35R22.

Size pages

Other comparisons with 305/35R22

Other comparisons with 305/30R24

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