Tires: tire age, cold climate, tire industry

Question
I have a 1997 Jag XJ6 whose spare tire has never been out of the trunk.  Can I assume that this is too old and should be junked or can I put it into rotation safely?

Thanks so much,

Jack

Answer
Jack,

Here's my standard response to questions about tire age:

Recent bulletins from the tire industry indicate that tires degrade simply due to time.  The age of a tire is important even if the tire is unused.  There some disagreement over how to best express this age limitation, but my take is:

If you live in a hot climate (AZ, CA, NV, TX, and FL) then the limit is six years.  If you live in a cold climate (MN, ND, WI, MT, etc), then the limit is 10 years.  States in between are  ..... ah ........ in between.

So, yes, an 11+ year old tire would not be suitable for use.