265/45R22 vs 305/40R22

305/40R22 is 0.22 in (5.5 mm) taller than 265/45R22, a +0.69% diameter difference. With the speedometer set for 265/45R22, an indicated 60 mph is 60.4 mph on 305/40R22.

Is this a safe swap?

Diameter difference +0.69%: under 1%

By overall diameter alone, 305/40R22 is a near match for 265/45R22; the speedometer changes by less than 1%. 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.

265/45R22 vs 305/40R22 differences
Measurement	265/45R22	305/40R22	Difference	% diff
Overall diameter	31.39 in (797.3 mm)	31.61 in (802.8 mm)	+0.22 in (+5.5 mm)	+0.69%
Sidewall height	4.69 in (119.3 mm)	4.80 in (122.0 mm)	+0.11 in (+2.8 mm)	+2.31%
Section width	10.43 in (265.0 mm)	12.01 in (305.0 mm)	+1.57 in (+40.0 mm)	+15.09%
Circumference	98.61 in (2,504.8 mm)	99.29 in (2,522.1 mm)	+0.68 in (+17.3 mm)	+0.69%
Revolutions per mile	643	638	−4	−0.69%

True speed with the speedometer calibrated for 265/45R22
Indicated	Actual on 265/45R22	Actual on 305/40R22	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.4 mph	+0.4 mph
75 mph	75.0 mph	75.5 mph	+0.5 mph

Ride-height change: 305/40R22 raises the vehicle by 0.11 in (2.8 mm) at the axle (half the +5.5 mm diameter difference).

305/40R22 is 0.22 in taller than 265/45R22 and 40 mm wider, a 0.69% difference in overall diameter.

With the speedometer calibrated for 265/45R22, an indicated 60 mph is actually 60.4 mph on 305/40R22, and revolutions per mile change from 643 to 638.

Both sizes mount on 22-inch wheels.

Size pages

Other comparisons with 265/45R22

Other comparisons with 305/40R22

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