TeamSwift

I only drive my 91 vert in the summer here in Utah, it is garaged all the time. At my last inspection the guy mentioned, "Do you know these tires are 14 years old? I didn't, but if they are kept away from uv rays? The car only has 70,000 miles on it. Are the tires safe?

Newer tire rubber compound may degrade even faster than older tires, as environmentally friendly compounds are increasingly being used.

Generally speaking, tires that are mounted on the car should be replaced within 7-10 years of the tire date code, regardless of distance travelled. Cracking is only one indicator of impending tire failure. Wallowing, directional stability problems, or harsh ride are also indications that your tires are too old and should be replaced. They may still be okay for short distances at low speeds. You really don't want to risk having your tread peel off or separating from its casing at highway speeds.



See also:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=11