275/30R21 vs 245/30R22

245/30R22 is 0.29 in (7.4 mm) taller than 275/30R21, a +1.06% diameter difference. With the speedometer set for 275/30R21, an indicated 60 mph is 60.6 mph on 245/30R22.

Is this a safe swap?

Diameter difference +1.06%: within the ±3% guideline

By overall diameter alone, 245/30R22 falls inside the ±3% range commonly used as a guideline when replacing 275/30R21. 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.

275/30R21 vs 245/30R22 differences
Measurement	275/30R21	245/30R22	Difference	% diff
Overall diameter	27.50 in (698.4 mm)	27.79 in (705.8 mm)	+0.29 in (+7.4 mm)	+1.06%
Sidewall height	3.25 in (82.5 mm)	2.89 in (73.5 mm)	−0.35 in (−9.0 mm)	−10.91%
Section width	10.83 in (275.0 mm)	9.65 in (245.0 mm)	−1.18 in (−30.0 mm)	−10.91%
Circumference	86.38 in (2,194.1 mm)	87.30 in (2,217.3 mm)	+0.92 in (+23.2 mm)	+1.06%
Revolutions per mile	733	726	−8	−1.05%

True speed with the speedometer calibrated for 275/30R21
Indicated	Actual on 275/30R21	Actual on 245/30R22	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.6 mph	+0.6 mph
75 mph	75.0 mph	75.8 mph	+0.8 mph

Ride-height change: 245/30R22 raises the vehicle by 0.15 in (3.7 mm) at the axle (half the +7.4 mm diameter difference).

245/30R22 is 0.29 in taller than 275/30R21 and 30 mm narrower, a 1.06% difference in overall diameter.

With the speedometer calibrated for 275/30R21, an indicated 60 mph is actually 60.6 mph on 245/30R22, and revolutions per mile change from 733 to 726.

245/30R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 275/30R21.

Size pages

Other comparisons with 275/30R21

Other comparisons with 245/30R22

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