From Goodyear tires "Storing your RV" website;
https://www.goodyearrvtires.com/tire-storage.aspx Much has to do with how long several months will be....surface type and of course shade them from direct sun.
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My 11400 gvwr rv trailer sit in its shed for 6-7 months (winter storage) on limestone 1" crusher run with 2" X 8" under 16" LT E tires. I keep the tires pumped to max sidewall 52 weeks a year.