Tire identification number

The trade calls it the DOT number, which is why it is worth saying what the rule calls it. Under 49 CFR § 574.5 a new tire's identification number has three groups: a three-symbol plant code identifying the manufacturer or retreader, a six-symbol manufacturer's code that may describe the tire or identify the brand owner, and a four-digit date code whose first two digits are the week and last two the year of manufacture. It is moulded into one sidewall in the position the rule's figure shows. A retread carries a seven-symbol number with no manufacturer's code and an "R" beside it.

The DOT symbol next to the number is not part of the number; it is the manufacturer's certification that the tire meets a federal safety standard, placed in a fixed position relative to the TIN.

The number matters at the counter because § 574.8 makes an independent dealer record or hand over "the entire tire identification number" for every new tire sold, by one of three methods, two of them within 30 days. The tire registration entry has the three methods. A partial number, the last four digits a technician reads off the outside sidewall, is not the record the rule asks for.

In Wrenchy the number is a field on the tire's own record on the part line, one per tire with its position. The tire shops page has the rest of the tire day.