Every tire sold in the United States carries a DOT (Department of Transportation) identification number molded into the sidewall. This alphanumeric code is more than a regulatory requirement — it's a valuable source of information about where and when the tire was made. Knowing how to read it helps you manage inventory, verify tire age, and ensure compliance.
Where to Find the DOT Code
Look on the sidewall of the tire near the bead area (where the tire meets the rim). You'll see "DOT" followed by a series of characters. The full DOT code has 11-12 characters and is usually on one side of the tire. If you only see a partial DOT (without the last four digits), check the other sidewall.
Breaking Down the DOT Code
A typical DOT code looks like this: DOT H2AB CDEF 2425. Here's what each section means:
- H2 — Plant code (identifies the specific factory where the tire was manufactured)
- AB — Tire size code
- CDEF — Brand and design attributes (optional characters used by the manufacturer)
- 2425 — Date code (the most important part)
The Date Code: The Critical Four Digits
The last four digits of the DOT code indicate the week and year of manufacture. In our example, "2425" means the tire was manufactured in the 24th week of 2025 (approximately mid-June 2025).
This date code is critical for several reasons:
- Tire aging: Even unused tires degrade over time. Industry guidelines recommend that commercial tires be removed from service after 6-10 years from the date of manufacture, regardless of remaining tread depth.
- Warranty claims: Most manufacturer warranties start from the date of manufacture, not the date of purchase.
- Inventory management: FIFO (First In, First Out) inventory practices ensure you're selling the oldest stock first.
The Plant Code
The first two characters after "DOT" identify the manufacturing plant. The NHTSA maintains a database of plant codes. For example, if you're buying Onyx tires from Shandong Changfeng, you'll see a specific plant code associated with their facilities. This information is useful for traceability — if there's ever a recall or quality issue, the plant code narrows down exactly where the tire was made.
Why This Matters for Fleet Operators
As a fleet manager, you should be checking DOT codes at several points:
- At purchase: Verify that tires you're receiving are recently manufactured. Tires should ideally be less than 12-18 months old when you buy them.
- During inventory: Track manufacturing dates in your inventory system. Sell older stock first.
- At inspection: DOT officers can and do check tire age during roadside inspections. While there's no federal maximum age limit for commercial tires currently, tires older than 7 years may receive increased scrutiny.
- At replacement: When removing tires from service, record the DOT date code to track actual service life by brand and model.
Pre-2000 Date Codes
If you ever encounter a tire with only a three-digit date code, it was manufactured before 2000. For example, "248" would mean the 24th week of 1998 (or 1988 — the system was ambiguous). Needless to say, any tire with a three-digit date code should be removed from service immediately.
At Oryx, we maintain strict inventory rotation to ensure every tire we sell is fresh from the factory. Contact us if you have questions about any tire's manufacturing date.
