175/65R15 vs 225/40R17

225/40R17 is 0.13 in (3.3 mm) taller than 175/65R15, a +0.54% diameter difference. With the speedometer set for 175/65R15, an indicated 60 mph is 60.3 mph on 225/40R17.

Is this a safe swap?

Diameter difference +0.54%: under 1%

By overall diameter alone, 225/40R17 is a near match for 175/65R15; 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.

175/65R15 vs 225/40R17 differences
Measurement	175/65R15	225/40R17	Difference	% diff
Overall diameter	23.96 in (608.5 mm)	24.09 in (611.8 mm)	+0.13 in (+3.3 mm)	+0.54%
Sidewall height	4.48 in (113.8 mm)	3.54 in (90.0 mm)	−0.94 in (−23.7 mm)	−20.88%
Section width	6.89 in (175.0 mm)	8.86 in (225.0 mm)	+1.97 in (+50.0 mm)	+28.57%
Circumference	75.26 in (1,911.7 mm)	75.67 in (1,922.0 mm)	+0.41 in (+10.4 mm)	+0.54%
Revolutions per mile	842	837	−5	−0.54%

True speed with the speedometer calibrated for 175/65R15
Indicated	Actual on 175/65R15	Actual on 225/40R17	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.3 mph	+0.3 mph
75 mph	75.0 mph	75.4 mph	+0.4 mph

Ride-height change: 225/40R17 raises the vehicle by 0.06 in (1.6 mm) at the axle (half the +3.3 mm diameter difference).

225/40R17 is 0.13 in taller than 175/65R15 and 50 mm wider, a 0.54% difference in overall diameter.

With the speedometer calibrated for 175/65R15, an indicated 60 mph is actually 60.3 mph on 225/40R17, and revolutions per mile change from 842 to 837.

225/40R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 175/65R15.

Size pages

Other comparisons with 175/65R15

Other comparisons with 225/40R17

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