http://www.conti-tyres.co.uk/conticycle/technical_safety.shtml
"Tyre Maintenance
Take some simple steps to ensure you get the best possible life out of your Continental tyres.
Sunlight – Tyres do not respond well to prolonged sunlight (ultra violet) exposure. The tyre rubber will become weak and will eventually crack and break up. Store your cycle away from direct sunlight when possible.
Damp – Damp storage conditions will also shorten your tyres life. If you’ve been out in the rain, make sure your bike is left in a dry atmosphere immediately following your ride.
Not using the bike for a while? Store the bike upside down, or hang it up to prevent tyre deformation.
Inspection – Inspect your tyres before every ride. Check for cuts and wear & brush off any road debris attached to the tread.
Most importantly – Tyre pressure. Inflate your tyres to the recommended pressure in this guide. Carrying a heavy load? If so, then increase the pressure up to and including the maximum shown in this guide. "