305/30R24 vs 305/35R24

305/35R24 is 1.20 in (30.5 mm) taller than 305/30R24, a +3.85% diameter difference. With the speedometer set for 305/30R24, an indicated 60 mph is 62.3 mph on 305/35R24.

Is this a safe swap?

Diameter difference +3.85%: outside the ±3% guideline

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

305/30R24 vs 305/35R24 differences
Measurement	305/30R24	305/35R24	Difference	% diff
Overall diameter	31.20 in (792.6 mm)	32.41 in (823.1 mm)	+1.20 in (+30.5 mm)	+3.85%
Sidewall height	3.60 in (91.5 mm)	4.20 in (106.8 mm)	+0.60 in (+15.3 mm)	+16.67%
Section width	12.01 in (305.0 mm)	12.01 in (305.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	98.03 in (2,490.0 mm)	101.80 in (2,585.8 mm)	+3.77 in (+95.8 mm)	+3.85%
Revolutions per mile	646	622	−24	−3.71%

True speed with the speedometer calibrated for 305/30R24
Indicated	Actual on 305/30R24	Actual on 305/35R24	Difference
30 mph	30.0 mph	31.2 mph	+1.2 mph
60 mph	60.0 mph	62.3 mph	+2.3 mph
75 mph	75.0 mph	77.9 mph	+2.9 mph

Ride-height change: 305/35R24 raises the vehicle by 0.60 in (15.3 mm) at the axle (half the +30.5 mm diameter difference).

305/35R24 is 1.20 in taller than 305/30R24 and the same width, a 3.85% difference in overall diameter.

With the speedometer calibrated for 305/30R24, an indicated 60 mph is actually 62.3 mph on 305/35R24, and revolutions per mile change from 646 to 622.

Both sizes mount on 24-inch wheels.

Size pages

Other comparisons with 305/30R24

Other comparisons with 305/35R24

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