I just replaced my OEM Goodyear 245/70/19.5 with Roadmaster (by Cooper) RM170+ which were highly recommended by my tire shop who only deal in truck and RV tires. I told him that I wanted Toyo or Sumitomo as that is what he generally installs on the 22.5 RVs, but he insisted that they have had better results with the RM170+ in the 19.5 RVs and trucks. OEM was a G and these are H with a higher speed rating as well. I have only driven 40 miles, but they are quieter and smoother than my old tires with 38,000 miles.
I kept one old tire for a spare and mounted it on the Roadmaster hitch mount which is such a great design.