Tires: tires- replace?, cold climate, tire industry

Question
My 2001 Explorer's tire still look good with adequate tread but I have heard that when tires are this old they should be replaced. The tires have 37000 miles on them and have started leaving black marks on the driveway

Answer
Mose,

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 I think your tires need to be replaced.