Tires: motorcycle tires data, passenger car tires, motorcycle tires

Question
I read an article detailing all the letters/numbers on a motorcycle tire but can no longer find it. How do you tell when a tire was manufactured and how long of  a shelf life do they have if new.

Answer
Skip,

Motorcycle tires are covered by similar regulations as passenger car tires and the US government requires ALL tires that operate on the street to have the same form of tire serial numbers.

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.

The issue of shelf life is being hotly debated.  There is one school of thought that says under the proper conditions a tire can last almost forever.  Needless to say this would require extraordinary storage conditions and those just do not exist in the real world.

But there is a school of thought that says that unusually harsh storage conditions have to be considered in any statement that is published to the general public.

But I tend to take a middle of the road approach and assume that most folks would store new tires in cool, dry, dark places away from sources of heat and ozone (electric motors) and in that case tires could be stored as long as 5 years before first use.