305/40R20 vs 265/35R22

265/35R22 is 0.30 in (7.7 mm) shorter than 305/40R20, a −1.02% diameter difference. With the speedometer set for 305/40R20, an indicated 60 mph is 59.4 mph on 265/35R22.

Is this a safe swap?

Diameter difference −1.02%: within the ±3% guideline

By overall diameter alone, 265/35R22 falls inside the ±3% range commonly used as a guideline when replacing 305/40R20. 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.

305/40R20 vs 265/35R22 differences
Measurement	305/40R20	265/35R22	Difference	% diff
Overall diameter	29.61 in (752.0 mm)	29.30 in (744.3 mm)	−0.30 in (−7.7 mm)	−1.02%
Sidewall height	4.80 in (122.0 mm)	3.65 in (92.8 mm)	−1.15 in (−29.2 mm)	−23.98%
Section width	12.01 in (305.0 mm)	10.43 in (265.0 mm)	−1.57 in (−40.0 mm)	−13.11%
Circumference	93.01 in (2,362.5 mm)	92.06 in (2,338.3 mm)	−0.95 in (−24.2 mm)	−1.02%
Revolutions per mile	681	688	+7	+1.03%

True speed with the speedometer calibrated for 305/40R20
Indicated	Actual on 305/40R20	Actual on 265/35R22	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.4 mph	−0.6 mph
75 mph	75.0 mph	74.2 mph	−0.8 mph

Ride-height change: 265/35R22 lowers the vehicle by 0.15 in (3.9 mm) at the axle (half the −7.7 mm diameter difference).

265/35R22 is 0.30 in shorter than 305/40R20 and 40 mm narrower, a 1.02% difference in overall diameter.

With the speedometer calibrated for 305/40R20, an indicated 60 mph is actually 59.4 mph on 265/35R22, and revolutions per mile change from 681 to 688.

265/35R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 305/40R20.

Size pages

Other comparisons with 305/40R20

Other comparisons with 265/35R22

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