I am puzzled by the suggestion that tire rubber will absorb solvents from asphalt, plastic or from anything else. I have mats on my garage floor that are made from recycled tires. They started their present incarnation as ground cover under a playground in the back yard. when the kids outgrew the playground, they moved inside. they are now about 30 yrs since being ground from old tires, so their original production was likely another 10 yrs before that. In the time that I have had them, there is absolutely no sign of anything affecting them chemically. They have had solvents on them many times, as I have used solvents to clean oil drippings off the surface. They have had road salt, sand, dust, dirt, mud, in short anything your RV tires might encounter. Chemically, the rubber seems to be completely inert. Mechanically, they are subject to the same damage as tires, ie extremely little. Even being outdoors for a number of years, there is no sign of UV damage.
Do we have a chemist in our midst who can put the concerns expressed in this and other threads, into perspective? I would be especially grateful if there is someone who can explain the reasons why RV tires are subject to age concerns despite no outward appearance of degradation, while car and light truck tires don't have the same concern. Do heavy trucks change their tires based on the DOT code? Are our RV tires different in some way? If so, what are the advantages of that difference to the RV owner?