165/65R14 vs 225/40R16

225/40R16 is 0.64 in (16.3 mm) taller than 165/65R14, a +2.86% diameter difference. With the speedometer set for 165/65R14, an indicated 60 mph is 61.7 mph on 225/40R16.

Is this a safe swap?

Diameter difference +2.86%: within the ±3% guideline

By overall diameter alone, 225/40R16 falls inside the ±3% range commonly used as a guideline when replacing 165/65R14. 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.

165/65R14 vs 225/40R16 differences
Measurement	165/65R14	225/40R16	Difference	% diff
Overall diameter	22.44 in (570.1 mm)	23.09 in (586.4 mm)	+0.64 in (+16.3 mm)	+2.86%
Sidewall height	4.22 in (107.3 mm)	3.54 in (90.0 mm)	−0.68 in (−17.2 mm)	−16.08%
Section width	6.50 in (165.0 mm)	8.86 in (225.0 mm)	+2.36 in (+60.0 mm)	+36.36%
Circumference	70.51 in (1,791.0 mm)	72.53 in (1,842.2 mm)	+2.02 in (+51.2 mm)	+2.86%
Revolutions per mile	899	874	−25	−2.78%

True speed with the speedometer calibrated for 165/65R14
Indicated	Actual on 165/65R14	Actual on 225/40R16	Difference
30 mph	30.0 mph	30.9 mph	+0.9 mph
60 mph	60.0 mph	61.7 mph	+1.7 mph
75 mph	75.0 mph	77.1 mph	+2.1 mph

Ride-height change: 225/40R16 raises the vehicle by 0.32 in (8.2 mm) at the axle (half the +16.3 mm diameter difference).

225/40R16 is 0.64 in taller than 165/65R14 and 60 mm wider, a 2.86% difference in overall diameter.

With the speedometer calibrated for 165/65R14, an indicated 60 mph is actually 61.7 mph on 225/40R16, and revolutions per mile change from 899 to 874.

225/40R16 mounts on a 16-inch wheel, a plus-2 fitment from the 14-inch wheel of 165/65R14.

Size pages

Other comparisons with 165/65R14

Other comparisons with 225/40R16

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