235/50R17 vs 225/40R19

225/40R19 is 0.17 in (4.2 mm) shorter than 235/50R17, a −0.63% diameter difference. With the speedometer set for 235/50R17, an indicated 60 mph is 59.6 mph on 225/40R19.

Is this a safe swap?

Diameter difference −0.63%: under 1%

By overall diameter alone, 225/40R19 is a near match for 235/50R17; 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.

235/50R17 vs 225/40R19 differences
Measurement	235/50R17	225/40R19	Difference	% diff
Overall diameter	26.25 in (666.8 mm)	26.09 in (662.6 mm)	−0.17 in (−4.2 mm)	−0.63%
Sidewall height	4.63 in (117.5 mm)	3.54 in (90.0 mm)	−1.08 in (−27.5 mm)	−23.40%
Section width	9.25 in (235.0 mm)	8.86 in (225.0 mm)	−0.39 in (−10.0 mm)	−4.26%
Circumference	82.47 in (2,094.8 mm)	81.95 in (2,081.6 mm)	−0.52 in (−13.2 mm)	−0.63%
Revolutions per mile	768	773	+5	+0.63%

True speed with the speedometer calibrated for 235/50R17
Indicated	Actual on 235/50R17	Actual on 225/40R19	Difference
30 mph	30.0 mph	29.8 mph	−0.2 mph
60 mph	60.0 mph	59.6 mph	−0.4 mph
75 mph	75.0 mph	74.5 mph	−0.5 mph

Ride-height change: 225/40R19 lowers the vehicle by 0.08 in (2.1 mm) at the axle (half the −4.2 mm diameter difference).

225/40R19 is 0.17 in shorter than 235/50R17 and 10 mm narrower, a 0.63% difference in overall diameter.

With the speedometer calibrated for 235/50R17, an indicated 60 mph is actually 59.6 mph on 225/40R19, and revolutions per mile change from 768 to 773.

225/40R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 235/50R17.

Size pages

Other comparisons with 235/50R17

Other comparisons with 225/40R19

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