Okay here is a copy of Goodyear's Care and Maintenance of RV Tires;
Storing Your Vehicle Without Removing the Tires
Ideally, a vehicle in storage should be placed on blocks to remove all weight from the tires. If the vehicle cannot be put on blocks, follow these steps for tire protection:
•Completely unload the vehicle so that minimum weight will be placed on the tires
•Inflate tires to recommended operating pressure plus 25%. Ensure that the rim manufacturer’s inflation capacity is not exceeded
•Be sure the storage surface is firm, clean, well drained and reasonably level
•Avoid moving the vehicle during extremely cold weather
•Move the vehicle at least every three months to prevent ozone cracking in the tire bulge area, as well as “flat-spotting” from the prolonged strain of sidewall and tread deflection
•Adjust inflation before putting the vehicle back into service
Somebody else can look up Michelin or whatever.