I've stocked up on tires from probikekit.com because of the incredible deals there and now have about 2 years supply of tires, plus I normally swap tires around a bit. I use Conti GP 4-Seasons in the spring on wet roads, Conti GP-4000's the rest of the year, Maxis cyclocross tires on my hybrid for roads to rails trails, Conti TT2000's for touring, etc. etc. I have a lot of tires around that are not on rims.
What is the best way to store tires for longer-term storage, i.e. several years? I keep them all in the basement so it's dark and cool. But I wonder about the folding tires, should they be unfolded and laid flat in storage?
What do you do?