TireSizesFinder

305/55R20 vs 33x12.50R22

33x12.50R22 is 0.21 in (5.3 mm) shorter than 305/55R20, a −0.63% diameter difference. With the speedometer set for 305/55R20, an indicated 60 mph is 59.6 mph on 33x12.50R22.

Is this a safe swap?

Diameter difference −0.63%: under 1%

By overall diameter alone, 33x12.50R22 is a near match for 305/55R20; 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: 305/55R20 (33.21 in) vs 33x12.50R22 (33.00 in)305/55R2033.21 in × 12.01 in33x12.50R2233.00 in × 12.50 in
Side profile and tread width, drawn to the same scale.
305/55R20 vs 33x12.50R22 differences
Measurement305/55R2033x12.50R22Difference% diff
Overall diameter33.21 in (843.5 mm)33.00 in (838.2 mm)−0.21 in (−5.3 mm)−0.63%
Sidewall height6.60 in (167.8 mm)5.50 in (139.7 mm)−1.10 in (−28.1 mm)−16.72%
Section width12.01 in (305.0 mm)12.50 in (317.5 mm)+0.49 in (+12.5 mm)+4.10%
Circumference104.33 in (2,649.9 mm)103.67 in (2,633.3 mm)−0.66 in (−16.7 mm)−0.63%
Revolutions per mile607611+4+0.63%
True speed with the speedometer calibrated for 305/55R20
IndicatedActual on 305/55R20Actual on 33x12.50R22Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.5 mph−0.5 mph

Ride-height change: 33x12.50R22 lowers the vehicle by 0.10 in (2.7 mm) at the axle (half the −5.3 mm diameter difference).

33x12.50R22 is 0.21 in shorter than 305/55R20 and 13 mm wider, a 0.63% difference in overall diameter.

With the speedometer calibrated for 305/55R20, an indicated 60 mph is actually 59.6 mph on 33x12.50R22, and revolutions per mile change from 607 to 611.

33x12.50R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 305/55R20.

Size pages

Other comparisons with 305/55R20

Other comparisons with 33x12.50R22

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