Tires: Jeep tires, jeep grand cherokee laredo, jeep grand cherokee

Question
Hello Barry,
I have a 2005 Jeep Grand Cherokee Laredo.  It needs new tires.  The spare tire has never been used.  The tire and the rim appear to be the same as those already on the Jeep.  Can I use this full time and just buy 3 new tires that match?
Thanks, Clark

Answer
Clark,

Here's the problem.

The spare is now about 4 years old.  You are going to match it with recently produced tires.

1)  Tires degrade with time.  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 if the tires wear at the same rate, the spare will be 8 years old when it is worn out.  There is a risk there.

2)  Anything that is produced is subject to revision.  This is true for many things, including tires.  A tire produced 4 years ago is not likely to be exactly the same as one produced yesterday.

3)  Any time you mount an odd tire on a vehicle there is a risk.  Vehicles tend to pivot around an odd tire in emergency maneuvers - just when you wouldn't want that to happen.  And the more different the tire is, the more the tendency.


So those are the drawbacks.