275/65R20 vs 325/45R22

325/45R22 is 0.56 in (14.2 mm) shorter than 275/65R20, a −1.64% diameter difference. With the speedometer set for 275/65R20, an indicated 60 mph is 59.0 mph on 325/45R22.

Is this a safe swap?

Diameter difference −1.64%: within the ±3% guideline

By overall diameter alone, 325/45R22 falls inside the ±3% range commonly used as a guideline when replacing 275/65R20. 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.

275/65R20 vs 325/45R22 differences
Measurement	275/65R20	325/45R22	Difference	% diff
Overall diameter	34.07 in (865.5 mm)	33.52 in (851.3 mm)	−0.56 in (−14.2 mm)	−1.64%
Sidewall height	7.04 in (178.8 mm)	5.76 in (146.3 mm)	−1.28 in (−32.5 mm)	−18.18%
Section width	10.83 in (275.0 mm)	12.80 in (325.0 mm)	+1.97 in (+50.0 mm)	+18.18%
Circumference	107.05 in (2,719.0 mm)	105.29 in (2,674.4 mm)	−1.76 in (−44.6 mm)	−1.64%
Revolutions per mile	592	602	+10	+1.67%

True speed with the speedometer calibrated for 275/65R20
Indicated	Actual on 275/65R20	Actual on 325/45R22	Difference
30 mph	30.0 mph	29.5 mph	−0.5 mph
60 mph	60.0 mph	59.0 mph	−1.0 mph
75 mph	75.0 mph	73.8 mph	−1.2 mph

Ride-height change: 325/45R22 lowers the vehicle by 0.28 in (7.1 mm) at the axle (half the −14.2 mm diameter difference).

325/45R22 is 0.56 in shorter than 275/65R20 and 50 mm wider, a 1.64% difference in overall diameter.

With the speedometer calibrated for 275/65R20, an indicated 60 mph is actually 59.0 mph on 325/45R22, and revolutions per mile change from 592 to 602.

325/45R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 275/65R20.

Size pages

Other comparisons with 275/65R20

Other comparisons with 325/45R22

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