The U.S. Department of Transportation requires that all tires sold in the United States be stamped with a code. The code looks something like this:
The two figures that immediately follow “DOT” are the code for the company and the plant that made the tire. This two-figure code can be two letters or a number and a letter. For example, if the code is DOT BF XX XXX XXX or DOT BE XX XXX XXX, it means the tire was made by B.F. Goodrich.
Here are the codes for union-made tires, built by United Steel Workers members, listed alphabetically by brand: