TireSizesFinder

33x12.50R20 vs 305/45R22

305/45R22 is 0.19 in (4.9 mm) shorter than 33x12.50R20, a −0.58% diameter difference. With the speedometer set for 33x12.50R20, an indicated 60 mph is 59.6 mph on 305/45R22.

Is this a safe swap?

Diameter difference −0.58%: under 1%

By overall diameter alone, 305/45R22 is a near match for 33x12.50R20; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 33x12.50R20 (33.00 in) vs 305/45R22 (32.81 in)33x12.50R2033.00 in × 12.50 in305/45R2232.81 in × 12.01 in
Side profile and tread width, drawn to the same scale.
33x12.50R20 vs 305/45R22 differences
Measurement33x12.50R20305/45R22Difference% diff
Overall diameter33.00 in (838.2 mm)32.81 in (833.3 mm)−0.19 in (−4.9 mm)−0.58%
Sidewall height6.50 in (165.1 mm)5.40 in (137.3 mm)−1.10 in (−27.8 mm)−16.87%
Section width12.50 in (317.5 mm)12.01 in (305.0 mm)−0.49 in (−12.5 mm)−3.94%
Circumference103.67 in (2,633.3 mm)103.07 in (2,617.9 mm)−0.61 in (−15.4 mm)−0.58%
Revolutions per mile611615+4+0.59%
True speed with the speedometer calibrated for 33x12.50R20
IndicatedActual on 33x12.50R20Actual on 305/45R22Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.6 mph−0.4 mph

Ride-height change: 305/45R22 lowers the vehicle by 0.10 in (2.5 mm) at the axle (half the −4.9 mm diameter difference).

305/45R22 is 0.19 in shorter than 33x12.50R20 and 13 mm narrower, a 0.58% difference in overall diameter.

With the speedometer calibrated for 33x12.50R20, an indicated 60 mph is actually 59.6 mph on 305/45R22, and revolutions per mile change from 611 to 615.

305/45R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 33x12.50R20.

Size pages

Other comparisons with 33x12.50R20

Other comparisons with 305/45R22

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.