Dhawk, Store in a dark, secure, cool, nitrogen environment.
OR SHIP TO ME AND I WILL PROTECT YOUR TIRES. AND I WILL PAY
FOR THE SHIPPING.
Happy New Year galewing
PS: lay on side---- in side----any cool place.
I was in the tire business for years and learned this. Tire are almost indestructible. You can store them anywhere and on anything. Their only enemy is sunlight, petroleum products, and heat. It doesn't matter if they're standing up, lying down, or tied to a tree, they will find they're shape once aired and driven on. Nothing you do to them is more stressful then what you do when you drive on them.
I won't quote it all, but mil-spec requires vertical storage (when possible) in dry place, 32 - 85 degrees, away from contaminents such as oil, gas, jet fuel, etc. and away from electrical motors, welders, fluorescent lights, etc. (ozone producers). The vertical positioning is mostly to tell folks not to stack them flat and on top of each other causing distortion. We are required to store aircraft tires standing up in specially made racks.
If it will be a while, I would find some way to wrap them up or cover them somehow. Maybe a large trash bag, plastic moving wrap, etc.