165/70R14 vs 225/40R16

225/40R16 is 0.01 in (0.2 mm) shorter than 165/70R14, a −0.03% diameter difference. With the speedometer set for 165/70R14, an indicated 60 mph is 60.0 mph on 225/40R16.

Is this a safe swap?

Diameter difference −0.03%: under 1%

By overall diameter alone, 225/40R16 is a near match for 165/70R14; 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.

165/70R14 vs 225/40R16 differences
Measurement	165/70R14	225/40R16	Difference	% diff
Overall diameter	23.09 in (586.6 mm)	23.09 in (586.4 mm)	−0.01 in (−0.2 mm)	−0.03%
Sidewall height	4.55 in (115.5 mm)	3.54 in (90.0 mm)	−1.00 in (−25.5 mm)	−22.08%
Section width	6.50 in (165.0 mm)	8.86 in (225.0 mm)	+2.36 in (+60.0 mm)	+36.36%
Circumference	72.55 in (1,842.9 mm)	72.53 in (1,842.2 mm)	−0.02 in (−0.6 mm)	−0.03%
Revolutions per mile	873	874	0	+0.03%

True speed with the speedometer calibrated for 165/70R14
Indicated	Actual on 165/70R14	Actual on 225/40R16
30 mph	30.0 mph	30.0 mph
60 mph	60.0 mph	60.0 mph
75 mph	75.0 mph	75.0 mph

Ride-height change: 225/40R16 lowers the vehicle by 0.00 in (0.1 mm) at the axle (half the −0.2 mm diameter difference).

225/40R16 is 0.01 in shorter than 165/70R14 and 60 mm wider, a 0.03% difference in overall diameter.

With the speedometer calibrated for 165/70R14, an indicated 60 mph is actually 60.0 mph on 225/40R16, and revolutions per mile change from 873 to 874.

225/40R16 mounts on a 16-inch wheel, a plus-2 fitment from the 14-inch wheel of 165/70R14.

Size pages

Other comparisons with 165/70R14

Other comparisons with 225/40R16

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