195/45R16 vs 225/40R16

225/40R16 is 0.18 in (4.5 mm) taller than 195/45R16, a +0.77% diameter difference. With the speedometer set for 195/45R16, an indicated 60 mph is 60.5 mph on 225/40R16.

Is this a safe swap?

Diameter difference +0.77%: under 1%

By overall diameter alone, 225/40R16 is a near match for 195/45R16; 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.

195/45R16 vs 225/40R16 differences
Measurement	195/45R16	225/40R16	Difference	% diff
Overall diameter	22.91 in (581.9 mm)	23.09 in (586.4 mm)	+0.18 in (+4.5 mm)	+0.77%
Sidewall height	3.45 in (87.8 mm)	3.54 in (90.0 mm)	+0.09 in (+2.3 mm)	+2.56%
Section width	7.68 in (195.0 mm)	8.86 in (225.0 mm)	+1.18 in (+30.0 mm)	+15.38%
Circumference	71.97 in (1,828.1 mm)	72.53 in (1,842.2 mm)	+0.56 in (+14.1 mm)	+0.77%
Revolutions per mile	880	874	−7	−0.77%

True speed with the speedometer calibrated for 195/45R16
Indicated	Actual on 195/45R16	Actual on 225/40R16	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.6 mph	+0.6 mph

Ride-height change: 225/40R16 raises the vehicle by 0.09 in (2.3 mm) at the axle (half the +4.5 mm diameter difference).

225/40R16 is 0.18 in taller than 195/45R16 and 30 mm wider, a 0.77% difference in overall diameter.

With the speedometer calibrated for 195/45R16, an indicated 60 mph is actually 60.5 mph on 225/40R16, and revolutions per mile change from 880 to 874.

Both sizes mount on 16-inch wheels.

Size pages

Other comparisons with 195/45R16

Other comparisons with 225/40R16

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