The date group, decoded
Four digits. A week and a year.
Example: 2322 · date group only, not the full TIN
- 23
- Week 23First two digits
- 22
- Year 2022Last two digits
Manufactured in the 23rd week of 2022.
The code gives a manufacture date. Installation history, present condition and replacement guidance require separate checks.
The last four digits of a modern DOT Tire Identification Number tell you the week and year a tire was manufactured. They do not tell you when it was installed or how much useful life remains. Read the date, record the history you can support, then check the guidance for your tires and vehicle.
This guide concerns passenger-car tires carrying U.S. DOT markings. The illustrated code is an example, not a tire Roadfelt inspected.
Find the date group safely
Locate the DOT marking and its Tire Identification Number, often shortened to TIN, on the sidewall. The complete marking may be on the inward-facing side; a missing date on the side you can see does not establish that the tire has no date. NHTSA explains where to look.
Read only markings you can reach safely with the vehicle parked on the ground. If the full number is inaccessible, ask a tire shop to read it. There is no need to lift the vehicle or get underneath it for this checklist.
Record each tire separately, including the spare if fitted. Note its current wheel position and take a clear photo when safely accessible. A photo of one tire is not evidence of the dates on the other tires.
Read week first, year second
In a four-digit date group such as 2322, 23 means the 23rd week and 22 means 2022. It is not a month/day code, and it does not specify an exact installation date. Continental's decoding guide explains the two pairs and the older three-digit format.
Keep the four digits together in your record. Do not substitute the tire size, load index or speed symbol for the date group. If a marking is unclear or appears to be an older three-digit date code, ask a tire professional to identify it and advise on replacement; do not invent a missing digit or a recent decade.
Keep three questions separate
When was it made? The date group answers this to the week and year. It remains the same if the tire is stored, sold, installed or moved to another wheel position.
When did it enter service? Look for an installation invoice or another record tied to the tire. Record the date and the evidence. When the start of service is unknown, write “unknown”; a seller's description of “nearly new” does not fill that gap. Keep invoices with the car's service history.
What condition is it in now? This needs separate attention. NHTSA says aging is affected by use, storage and environment and cannot be detected simply by looking at the tire. Good-looking tread does not settle that question. A date code is one input, not a condition report.
Read the manufacturer's age guidance carefully
The wording and the clock both matter. These are examples of published manufacturer guidance, not a universal replacement schedule:
| Source | Published guidance | Which date matters? |
|---|---|---|
| Michelin USA | After five years of service, have a trained tire professional inspect the tires thoroughly at least annually. As a precaution, replace them ten years after manufacture, including spares. | The inspection milestone uses time in service; the replacement recommendation uses manufacture date. |
| Continental USA | Replace tires, including spares, manufactured more than ten years earlier, even when appearance or tread seems acceptable. Follow the vehicle manufacturer's different timing where specified. | Manufacture date, alongside the instructions for the particular vehicle. |
Neither example promises that a tire will remain usable until that age. Continental explicitly notes that wear or other causes often require removal sooner. Read your vehicle manual and the tire maker's current instructions together; ask the manufacturer or a qualified tire professional to resolve unclear or conflicting guidance.
Make a record for the whole car
Use this Roadfelt worksheet before a tire-shop appointment or a pre-purchase inspection. Fill each blank from the actual tire or a supporting record. Write “unreadable,” “unknown” or “not fitted” when appropriate.
| Position at this check | Date code; decoded week/year | Installation date and evidence | Question for the tire shop |
|---|---|---|---|
| Front left | — | — | — |
| Front right | — | — | — |
| Rear left | — | — | — |
| Rear right | — | — | — |
| Spare, if fitted | — | — | — |
Add the date you checked and each tire's brand, model and size beside its photo. After rotation or replacement, update the positions so that an old note does not describe the wrong tire. Keep the date record separate from your cold tire-pressure targets.
Turn uncertainty into a specific next step
Bring the record to the tire professional and ask:
- Can you confirm the date codes I could not read?
- Which inspection and replacement guidance applies to this vehicle and these tires?
- What findings require attention now, and what remains unassessed?
- What should I record or schedule next, including for the spare?
Do not wait for an age milestone if there is damage or a change in performance. Michelin calls for immediate professional inspection of visible sidewall damage. NHTSA identifies pressure loss, noise or vibration as reasons to consult a tire professional. A recent date does not cancel those concerns; if a tire may be unsafe to drive on, ask how to arrange assistance rather than driving it to test the symptom.
Use the answers to update your maintenance plan. The useful outcome is a documented next action for each tire, not a reassuring age calculation with unresolved condition questions.
Sources
Primary sources checked October 19, 2026: NHTSA TireWise, Michelin USA's replacement guidance, Continental USA's tire-life guidance and Continental's date-code explanation, linked above. The diagram, record table and appointment questions are original Roadfelt editorial aids. No tire was inspected or tested. For other markets or specialist tire applications, confirm the relevant manufacturer instructions and local requirements.
Our approach: clear sources, clear limits, useful conclusions.
