LS-ONE_DAY

A friend of mine has really sturdy hangers on the wall of his garage and he hangs all of his spare wheels/tires on these. I know that having the tires sit with the tread on the ground isn't good for long periods of time because it can flatten but whenever I get a nice set of wheels/tires for nice weather (keeping the stockers for colder, not nice weather) hanging mine will not be an option. How do you guys recommend storing wheels and tires when not in use for months? I was going to just lay the wheels/tires down so that the tread faces out and stack them on top of each other but he said that isn't good either...