305/45R22 vs 33x12.50R22

33x12.50R22 is 0.19 in (4.9 mm) taller than 305/45R22, a +0.59% diameter difference. With the speedometer set for 305/45R22, an indicated 60 mph is 60.4 mph on 33x12.50R22.

Is this a safe swap?

Diameter difference +0.59%: under 1%

By overall diameter alone, 33x12.50R22 is a near match for 305/45R22; 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.

305/45R22 vs 33x12.50R22 differences
Measurement	305/45R22	33x12.50R22	Difference	% diff
Overall diameter	32.81 in (833.3 mm)	33.00 in (838.2 mm)	+0.19 in (+4.9 mm)	+0.59%
Sidewall height	5.40 in (137.3 mm)	5.50 in (139.7 mm)	+0.10 in (+2.4 mm)	+1.79%
Section width	12.01 in (305.0 mm)	12.50 in (317.5 mm)	+0.49 in (+12.5 mm)	+4.10%
Circumference	103.07 in (2,617.9 mm)	103.67 in (2,633.3 mm)	+0.61 in (+15.4 mm)	+0.59%
Revolutions per mile	615	611	−4	−0.58%

True speed with the speedometer calibrated for 305/45R22
Indicated	Actual on 305/45R22	Actual on 33x12.50R22	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	75.4 mph	+0.4 mph

Ride-height change: 33x12.50R22 raises the vehicle by 0.10 in (2.4 mm) at the axle (half the +4.9 mm diameter difference).

33x12.50R22 is 0.19 in taller than 305/45R22 and 13 mm wider, a 0.59% difference in overall diameter.

With the speedometer calibrated for 305/45R22, an indicated 60 mph is actually 60.4 mph on 33x12.50R22, and revolutions per mile change from 615 to 611.

Both sizes mount on 22-inch wheels.

Size pages

Other comparisons with 305/45R22

Other comparisons with 33x12.50R22

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