315/60R20 vs 325/50R22

325/50R22 is 0.09 in (2.2 mm) shorter than 315/60R20, a −0.25% diameter difference. With the speedometer set for 315/60R20, an indicated 60 mph is 59.9 mph on 325/50R22.

Is this a safe swap?

Diameter difference −0.25%: under 1%

By overall diameter alone, 325/50R22 is a near match for 315/60R20; 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.

315/60R20 vs 325/50R22 differences
Measurement	315/60R20	325/50R22	Difference	% diff
Overall diameter	34.88 in (886.0 mm)	34.80 in (883.8 mm)	−0.09 in (−2.2 mm)	−0.25%
Sidewall height	7.44 in (189.0 mm)	6.40 in (162.5 mm)	−1.04 in (−26.5 mm)	−14.02%
Section width	12.40 in (315.0 mm)	12.80 in (325.0 mm)	+0.39 in (+10.0 mm)	+3.17%
Circumference	109.58 in (2,783.5 mm)	109.31 in (2,776.5 mm)	−0.27 in (−6.9 mm)	−0.25%
Revolutions per mile	578	580	+1	+0.25%

True speed with the speedometer calibrated for 315/60R20
Indicated	Actual on 315/60R20	Actual on 325/50R22	Difference
30 mph	30.0 mph	29.9 mph	−0.1 mph
60 mph	60.0 mph	59.9 mph	−0.1 mph
75 mph	75.0 mph	74.8 mph	−0.2 mph

Ride-height change: 325/50R22 lowers the vehicle by 0.04 in (1.1 mm) at the axle (half the −2.2 mm diameter difference).

325/50R22 is 0.09 in shorter than 315/60R20 and 10 mm wider, a 0.25% difference in overall diameter.

With the speedometer calibrated for 315/60R20, an indicated 60 mph is actually 59.9 mph on 325/50R22, and revolutions per mile change from 578 to 580.

325/50R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 315/60R20.

Size pages

Other comparisons with 315/60R20

Other comparisons with 325/50R22

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