Tires: Tire age / serial #s, 4 digits, goodyear eagle

Question
I own a 1984 Monte Carlo with 15 k miles - I can't find any info on date codes for tires for my Goodyear Eagle GT tires - the only #'s I could find that appear close to serial #'s are 256366, 255292, 256070 (2 ea) followed by    -GW-21MMV is there a date code somehow incorporated in these numbers - I know this vehicle was stored in a temp controlled enviroment for the last 20+ years and was told everything was original equipment. I think the tire #'s should match if they are all original.

Answer
Tom,

Here's how to tell how old the tires are:

First locate the letters "DOT" on the sidewall of the tire.  Nearby will be the DOT code.  DOT codes are 10 to 12 digits long.  BTW the digits can be numbers or letters.

The first 2 digits are a code for the manufacturing plant.  

The next 2 digits are a code for the tire size.  

The next 3 or 4 digits are a code for the type of tire.  

The last 3 or 4 digits are the date code.  The format is week/week/year/year or week/week/year.  These are always numbers.

Starting in the year 2000, the date coding used was 4 digits.  That means the largest number you should see for the year is 09.  Before 1999 the format was 3 digits.  1999 and 2000 are transition years, so you will find both 3 and 4 digits.

The date code only has to be on one side – and it is permissible for there to be a partial DOT code, so long as one side has the complete code.

Your tires should have been made in late 1983 or early to mid 1984.  That means the date code should be XX3 or XX4.  Also, the convention was to mount the tires with the DOT code inboards - which means you will have to get under the car to see them.

But you should be aware that 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.

In your case, 20 years - even in a temperature controlled environment - are too old to consider for anything other than static usage - that is, not at any speed.