Tires: Car tire life, bf goodrich tires, 4 digits

Question
I have been reading about the danger of tire aging.  I purchased my new car 2 years ago, and just read about how the serial code will tell you the age of the tires.  The last four letters and numbers of my car are FB21.  From my assumption, that would be tires that were made the second month of 1991.  Is that correct? They are BF Goodrich tires, and I am concerned about the age of the tire, and wonder what the legal age of the tires are that are sold with new cars, despite the road time.  thanks for your reply, Day

Answer
Day,

DOT codes are a 10 to 12 digit number located near the letters "DOT".  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 is 4 digits.  That means the highest number you should see for the year is 08.  Before 1999 the format was 3 digits.  1999 and 2000 are transition years, so you will find both 3 and 4 digits.


I assume you got a partial DOT code and the date code is missing.  Date codes are only required on one side of the tire.  Look at the other side.