A complete DOT code will be 10-12 letters and numbers and end in four numbers. The following letters are generally not used in DOT codes: G, I, O, Q, S, and Z.
If you do not see the letters DOT or only see 4-6 letters and/or numbers, the complete DOT code is on the opposite side of the tire. If your full DOT code ends in only three numbers, the tire was manufactured prior to 2000 and must be replaced. Tires manufactured prior to 2000 will not produce a Tire Facts Report.
A complete DOT code will looks like this:
IMPORTANT: TIRE FACTS DOES NOT WORK FOR RE-TREADED TIRES!
If the tire’s DOT code is preceded by the letter “R,” Tire Facts will not provide accurate information.