Marv
I've never heard this..... and would believe its an old wives tale... . batteries used to loose their charge from moisture on concrete, but that was when we had very porous cases for batteries... . todays modern cases offer great resistance to the moisture and electrical discharge... . I can only assume that since tires are stacked and stored on concrete in warehouses all over the country that if there was a problem they would store them differently...
I have asked a good friend who works for Brigstone at the factory level about taking the weight off the tire... and was going to ask one of the engineers but hasn't gotten back to me yet... .