Identify U.S. retread markings and distinguish retreader TINs from casing codes

The short answer

Under current U.S. rules (49 CFR 574.5), a retreader must permanently mold or brand its own Tire Identification Number (TIN) into at least one sidewall of every retreaded tire. That TIN has seven symbols. The first three are a plant code assigned by the National Highway Traffic Safety Administration (NHTSA) that identifies the retreader. The last four are a date code giving the week and year the tire was retreaded. A separate letter R marks the tire as a retread, but the R is not part of the TIN.

A retread can also carry the original TIN from when the casing was built as a new tire. That casing code identifies the tire manufacturer's plant and the casing's manufacture date. It does not identify who retreaded the tire or when. Current new-tire TINs contain a six-symbol manufacturer's code between the plant code and the date code, and that six-symbol code is not allowed in a retread TIN. That difference is the quickest way to tell the two codes apart.

One condition changes the picture. Until April 13, 2025, retreaders were allowed to use older optional TIN formats that could include extra matrix or size and descriptive codes. A retread made before that date may therefore carry a retreader TIN longer than seven symbols.

Key terms

• Casing: the body of a used tire that receives new tread during retreading.
• Retreader: the business and plant that applied the new tread.
• TIN (Tire Identification Number): the federally required code identifying the plant that produced or retreaded a tire and the week and year it did so.
• Plant code: the first three symbols of a TIN, assigned by NHTSA to a specific plant.
• Date code: the final four digits of a current TIN. The first two digits are the week and the last two are the year.

How a current retreader TIN is built

PPP WWYY

PPP  = NHTSA-assigned plant code of the retreader
WW   = week of retreading (01-52/53)
YY   = last two digits of the year of retreading

Illustrative example only: a marking shown as PPP 3026 would mean the tire was retreaded in the 30th week of 2026 at the plant assigned code PPP. The letters PPP are a placeholder, not a real plant assignment. A standalone R molded or branded elsewhere on the sidewall marks the tire as a retread. Do not count the R as one of the seven TIN symbols.

Retreader TIN vs. original casing TIN

Feature	Retreader TIN (current format)	Original casing TIN
Who it identifies	The retreading plant	The tire manufacturer's plant that built the casing
Structure	7 symbols: 3-symbol plant code + 4-digit date code	Current new-tire format: plant code + six-symbol manufacturer's code + 4-digit date code
What the date means	Week and year of retreading	Week and year the casing was manufactured
Required on a retread?	Yes. The retreader must apply its own TIN.	May remain on the casing, but it does not substitute for the retreader's TIN

NHTSA has interpreted the rules to mean that a truck-tire retreader must apply its own TIN. Leaving only the original manufacturer's identification on the casing is not sufficient. In a 2007 interpretation on bus retreads, NHTSA also treated the original casing markings and the retreader's required TIN as separate items and allowed the casing markings to remain in the context it addressed. A retread showing two TINs is therefore normal. Read each one for what it identifies, and do not mix their dates.

Older retread formats you may still see

Retreads produced before April 13, 2025 may carry an optional older format. In that format, matrix or size codes and descriptive codes can sit between the plant code and the date. These TINs are longer than seven symbols, so length alone cannot tell you which code is the casing TIN. On these tires, read the first three symbols as the plant code and the final group as the date. Then confirm the plant code with the lookup procedure below. Much older tires may show a three-digit date code from an earlier era of the rules. That format is historical, and current retreads must use the four-digit week-and-year code.

The R, the DOT symbol and other branded text

• R: identifies the tire as a retread. It stands apart from the TIN.
• DOT: certifies that the tire conforms to an applicable Federal Motor Vehicle Safety Standard (FMVSS). It appears only where such a standard applies. NHTSA has explained that non-passenger retreads, such as truck and bus retreads, have no applicable FMVSS, although the Part 574 identification requirements still apply. The presence or absence of DOT tells you nothing about who retreaded the tire. The TIN does.
• Other branded text: tread design names, retread brand names, process names and similar markings are not NHTSA plant codes. Confirm what they mean through the documentation of the company that owns them, not through the plant-code lookup.

Where to look on the tire

The rule requires the retreader TIN on at least one sidewall, not both. Inspect both sidewalls all the way around. On a mounted tire, the retreader TIN may face inboard, so you may need to look from under the vehicle or wait until the tire is dismounted. Clean the sidewall and use a flashlight at a low angle so molded or branded characters cast shadows. Transcribe exactly what you see, including any spacing between groups. If a character is unclear, mark it as uncertain instead of guessing.

Verify the retreader's identity from the plant code

The retread industry's published lookup procedure uses NHTSA's Manufacturer Information Database (MID):

• 1. Open the MID.
• 2. Select Equipment Plants (Tires, Brake Hoses and Glazing).
• 3. Under Equipment Type, choose Retread.
• 4. Enter the three-symbol plant code from the start of the retreader TIN.
• 5. Run the search and note the retreader name and location returned.

If the code returns no retread plant, re-check your transcription. Also make sure you did not enter the plant code from the casing TIN. A casing plant code belongs to a tire manufacturer and will not appear under the Retread equipment type. If no retreader TIN can be found on either sidewall, ask the seller or fleet supplier for the retreader's identification. The original casing code alone does not identify the retreader.

A simple identification worksheet

Keep each marking in its own row so the casing and retread data never get mixed:

Marking	Exact text as seen	Sidewall location	Format and date meaning	Plant code	Date code	How verified
Original casing TIN			New-tire format; date = casing manufacture			Manufacturer's records
Retreader TIN			Current 7-symbol or pre-April 13, 2025 optional format; date = retreading			MID lookup under Retread
Separate R			Retread indicator, not part of TIN	n/a	n/a	Visual
Other branded text			Brand or tread name	n/a	n/a	Owner's documentation

Hypothetical lookup exercise: transcribe the retreader code exactly as observed, run the MID search, and record the organization and location it returns. Record the casing manufacture date and the retreading date in separate fields. The lookup confirms only who retreaded the tire and where. It says nothing about the tire's condition, its suitability for a particular vehicle or service, or whether it should be replaced. Those questions need a physical inspection by a qualified tire professional and the applicable vehicle and fleet requirements.