Determining the Age of a Tire and Reading the Code

Since 2000, the week and year the tire was produced has been provided by the last four digits of the Tire Identification Number (TIN) with the 2 digits being used to identify the week immediately preceding the 2 digits used to identify the year.

Example of a tire manufactured since 2000 with the current Tire Identification Number format:

tire date code since 2000

In the example above:
DOT H2LF YA9J 3507
35—Manufactured during the 35th week of the year
07—Manufactured during 2007

If you don't visibly see the DOT tire code with the date code from the outside view, then you'll need to view the other side of the tire.

Tire Replacement Age

According to the The Tire Safety Group and the NTSB Tire Safety Symposium (PDF), it is recommended that all tires older than six years should be replaced regardless of the tread depth or appearance. Another excellent resource is this article, How to Know When to Replace Tires.

However, RV tire expert Roger Marble says...

Due to trailer suspension design, there are unique forces such as "Interply Shear" placed on multi-axle trailer tires. This unique force causes about 24% higher shear forces than seen on motorized vehicles. This means you would need to run a decreased load (maybe 25% to 50% less) to get the same life on a multi-axle trailer application than the same tire on a tow vehicle application."

Roger does not know of any direct comparison in real life testing, so, he can only guess at the above figures, other than the 24% that comes from Finite Element computer simulation which is a well developed tool in automotive circles other than the RV industry.

You can read more about this on Roger's blog.

Generally, it is recommended that multi-axle trailer tires be replaced every four to five years regardless of regardless of the tread depth or appearance.

Where was my tire manufactured?

The Tire Safety Group (TSG) maintains the most current information. Please visit this page or download the TSG's free Tire Facts app to your mobile device.

The tire manufacturer is assigned a tire plant code that forms the first two digits of the DOT code. In the example picture below, the plant code is AT. The tire was manufactured in England.