NASCAR Racing: nascar tire codes, national speedway, friend of mind

Question
I purchased a used nascar tire at the Newhampshire national speedway on 9/17 for a close friend of mind who very Ill. The gentelman explained the crayon marking of the #8 on the bottom of the tire was from Dale Jr.
 The sidewall has the imprinted series "D6344". can you give me some history of it's origin. The man did not have the code book to explain what race it came from? Please help. I would like to have some history on it before i give it to him. Thank you very much. Ken Brown

Answer
I can't really give you a history of that tire. I can tell you that the D code is used to identify the tire as being for a certain track and whether it's a left or right side tire. At each track the Goodyear people will have a D code listed for each side of the car, some are used at more than one track, some are used at only one track. They change them as they develop new tires for each track during testing.
The #8 could very well mean it was used on the #8 car but could also designate set #8 for some other car. Barring any other numbers in crayon the tire I would bet it was used by the #8 car.
Sorry I can't be more specific but since I don't work at the tracks anymore I can't tell you what code is being used at what track and for which side of the car.