A tire's plant of origin and date of manufacture are located on each tire. These can be determined by examining the series of letters and numbers called the Tire Identification Number (TIN) which follow the letters "DOT" on the tire sidewall.
In order to find the week and year of production for tires manufactured after the year 1999, look at the last four numbers of the TIN. It will identify the week and year in which the tire was manufactured. The first two numbers identify the week and the last two numbers identify the year of manufacture. Thus, a TIN ending with "0309" indicates that the tire was made during the third week of 2009 and would appear as DOTXXXXXXX0309 on the sidewall of the tire.