It has to be the WEIGHT on RV tires that is the prime culprit in destroying them prematurely ... nothing else explains "dry rot" to my satisfaction.
Here's my "proof": I had the same Cooper tires on my PU truck here in (relatively) dry California a LONG TIME ... at least 12 years with no apparent "dry rot" at all ... only tread wear. I replaced them this year due entirely to tread wear. This truck has always been kept outdoors under a LOT of sun. But here's the big-proof-gotcha ... the tires were two sizes over stock size, so their weight carrying capacity was well over what the truck had on it for 98% of those tires' life. In other words, the tires were way under-loaded day after day year after year. What other thing could their extreme life be attributed to?? UNLESS ... Cooper (back then - in at least in those tires) used some super formula for the material it in it's tires ... which I doubt.
What weight does to RV tires is make them flex a lot when under way or when sitting not being used. That's why I always use high pressures in my RV's tires regardless of how hard it makes the RV ride ... so that this high pressure will keep tire sidewall flexing/bending to a minimum under the high loads that an RV is continuously applying to it's tires.
I'm open to any other explanation that makes sense as to why my lightly loaded pickup truck's unprotected tires never dry rotted for such a long time in a 10-20% RH climate ... as compared to heavily loaded RV tires.
