All tires must have a DOT, or Department of Transportation number, which indicates the tire has passed all minimum DOT standards for sale in the U.S. This code represents the manufacturer and the plant it was manufactured at (R8) and the size (LN). Also, an optional code for manufacturing (LMJR) which specifies the construction, tread pattern and category of the tire. The week (46) and year (10) the tire was produced are at the end of the code.