For long term storage, tire pressure should be increased 25% from inflation required for the loaded vehicle. Care should be taken to avoid prolonged tire contact with petroleum based substances. The RV should be moved every three months to prevent flat spotting and ozone cracking at the tire sidewall flex point. Flat spots usually disappear when the tires warm up after a 25+ mile drive. Flat spotting which occurs on vehicles not moved for six or more months may not disappear. If you use leveling blocks under your tires, the blocks should be large enough so the entire foot print of the tire will fit on them.