305/30R21 vs 295/25R22

295/25R22 is 0.40 in (10.1 mm) shorter than 305/30R21, a −1.41% diameter difference. With the speedometer set for 305/30R21, an indicated 60 mph is 59.2 mph on 295/25R22.

Is this a safe swap?

Diameter difference −1.41%: within the ±3% guideline

By overall diameter alone, 295/25R22 falls inside the ±3% range commonly used as a guideline when replacing 305/30R21. 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.

305/30R21 vs 295/25R22 differences
Measurement	305/30R21	295/25R22	Difference	% diff
Overall diameter	28.20 in (716.4 mm)	27.81 in (706.3 mm)	−0.40 in (−10.1 mm)	−1.41%
Sidewall height	3.60 in (91.5 mm)	2.90 in (73.8 mm)	−0.70 in (−17.7 mm)	−19.40%
Section width	12.01 in (305.0 mm)	11.61 in (295.0 mm)	−0.39 in (−10.0 mm)	−3.28%
Circumference	88.61 in (2,250.6 mm)	87.36 in (2,218.9 mm)	−1.25 in (−31.7 mm)	−1.41%
Revolutions per mile	715	725	+10	+1.43%

True speed with the speedometer calibrated for 305/30R21
Indicated	Actual on 305/30R21	Actual on 295/25R22	Difference
30 mph	30.0 mph	29.6 mph	−0.4 mph
60 mph	60.0 mph	59.2 mph	−0.8 mph
75 mph	75.0 mph	73.9 mph	−1.1 mph

Ride-height change: 295/25R22 lowers the vehicle by 0.20 in (5.1 mm) at the axle (half the −10.1 mm diameter difference).

295/25R22 is 0.40 in shorter than 305/30R21 and 10 mm narrower, a 1.41% difference in overall diameter.

With the speedometer calibrated for 305/30R21, an indicated 60 mph is actually 59.2 mph on 295/25R22, and revolutions per mile change from 715 to 725.

295/25R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 305/30R21.

Size pages

Other comparisons with 305/30R21

Other comparisons with 295/25R22

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