When tires are stored they should be stored in a cool, dry place away from sources of sunlight, heat and ozone such as hot pipes and electric motors.
Tires should be stored so there is no danger of water collecting inside them. Be sure that surfaces on which tires are stored are clean and free from grease, fuels, or other substances which could deteriorate the rubber. Tires exposed to these materials during storage or driving may be weakened and subject to sudden failure. Also, be sure to allow air to circulate around all sides of the tires, including underneath, to prevent moisture damage.
When storing tires flat (one on top of the other), stack so that tires on the bottom retain their shape and rotate the stack on a regular basis to maintain the shape of the lowest tires.
If storing tires outdoors, protect them with an opaque waterproof covering and elevate them from the ground. Do not store tyres on black asphalt, other heat-absorbent surfaces, snow-covered ground or sand.