Well a lot of it depends on the tire itself. Bill Boards do NOT lend themselves to storage no matter how you do it. They just age like crazy. Out of the sunlight for sure, temperature controlled are storeage fundamentals. In fact, if I was thinking long term storage I'd put them in a opaque garbage sack to keep ALL light out. No way you want any weight on them, if there on a car, jack it up, get the weight off the tire AND the springs as far as that goes.
My first set of Bill Boards were brand new and within a few months started to crack all over the side wall. They were literally just falling apart before my eyes!! I'm thinking they were in deep storage in some wharehouse and somebody saw me coming (the basturds).
