FWIW, Michelin changed the sidewall material a few years ago used in their LT225/75R16E tires. They call this their "Defender" series.
I hope this change was to stop the premature sidewall cracking problem, as I now have six M&S LT215/85R16E Defender tires on our Class C.
Those "C" class of tires look interesting if available with M&S treads. I would like the thickest, heaviest, most rugged M&S tires in 215/85R16 size I could find for our Class C to ensure optimum reliability and safety when off-highway on rough/rocky surfaces with our rig. (That is assuming we could take the stiffer highway ride from stiffer tires!)