I had this same experience as well. The 19's actually seemed to be a smoother ride when I put them on. Almost as if the slightly larger diameter rolls over bumps easier than 18's. Kind of analogous to mountain bikes with larger wheels like 29'ers.
That doesn't stack up as the rolling diameter of the 18's with tires at 225/40/18 is larger than the rolling diameter of 19's with 225/35/19 tires. :iono: