Had a set of 245/70R x 19.5 KSRs on the coach from April 2011 until March 2020 with 53,000 miles on them. Kept them covered when at home and no Armor All or other such products ever used. Bucket and brush mild soap when I did clean them. 85 PSI inflation to match GAWR plus extra for variables. No strange tread wear patterns, no sidewall cracking or other such age related degrading of the tire. No complaints but I drove the new to me, first ever Class A I owned, home back in April 2011 so I don't have much to compare with other than my daily driver which isn't a comparison.
Replaced them with a set Uniroyal RS20. Ride is about the same. Sold the Kelly's on Craig's List to a guy with a flat bed wrecker for $75 each. The tires cost me $289.23 each installed back in 2011.
2006 Hurricane 31D built on a 2006 Ford F53