Determining Tire Age

[Jerry Winchester]

Someone mentioned knowing how to read the code on a tire to determine its date of manufacture.

I don't know if it is standard for all tires (I suspect it is) but I have Goodyear tires in every position on my coach and they look good and have good tread depth, but I am curious how old they are.

[Jon Wehrenberg]

Try this link:

http://www.tirerack.com/tires/tirete....jsp?techid=11

The rule of thumb that has been thrown around is 6 years. I subscribe to that for the moment. I say it that way because I have presumed the UV resistance of truck tires is something that may have an affect on that lifespan. For example, except for trips, my bus is garaged and the door in front of the bus is almost never opened. The flip side to that is that I have read articles that suggest the compounds in the rubber formulation that contribute to to the life of the tire are released through use, and just sitting is detrimental.

If anybody wants to make a contribution to the POG II rally seminar offerings here is a good topic that will require a lot of research and maybe even some direct conversations with the technical people at companies such as Michelin, Goodyear, etc.

[Jerry Winchester]

When it comes to determining the age of a tire, it is easy to identify when a tire was manufactured by reading its Tire Identification Code (serial number). Unlike vehicle identification numbers (VINs) and the serial numbers used on many other consumer goods (which identify one specific item), Tire Identification Codes are really batch codes that identify which week and year the tire was produced.

The U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) requires that Tire Identification Code be a combination of eleven or twelve letters and numbers that identify the manufacturing location, tire size, manufacturer's code, and week and year the tire was manufactured.

Today, the week and year the tire was manufactured is contained in the last four digits of the serial number, with the 2 digits used to identify the week a tire was manufactured immediately preceding the 2 digits used to identify the year.

Examples of tires manufactured since 2000 with this Tire Identification Code format:

XXXXXXXX 0600
XXXXXXXX 0600 06 - Manufactured during the 06th week of the year
XXXXXXXX 0600 00 - Manufactured during 2000

And

XXXXXXXX 0604
XXXXXXXX 0600 06 - Manufactured during the 06th week of the year
XXXXXXXX 0604 04 - Manufactured during 2004

The Tire Identification Code for tires produced prior to 2000 was based on the assumption that no tire would be in service for ten years. They were required to provided the same information, with the week and year the tire was built contained in the last three digits. The 2 digits used to identify the week a tire was manufactured immediately preceded a single digit used to identify the year.

For example, if the Tire Identification Code on a tire reads:

XXXXXXXX 0680
XXXXXXXX 0600 06 - Manufactured during the 06th week of the year
XXXXXXXX 0680 8 - Manufactured during the 8th year of the decade

While the previous serial number format identified that a tire was built in the 9th year of a decade, there was no universal identifier that confirmed which decade (tires produced in the 1990s may have a small triangle following the Tire Identification Code to identify the decade). The Tire Identification Code format used since 2000 accurately confirms the year.

And finally, hold on to your sales receipts. Most tire manufacturer's warranties cover their tires for four years from the date of purchase, or five years from the week the tires were manufactured. So if you purchase new tires that were manufactured exactly two years ago they will be covered for a total of six years (four years from the date of purchase) as long as you have your receipt. If you lose your receipt, your tires' warranty coverage will end five years from week the tire was produced (resulting in the tire manufacturer's warranty coverage ending only three years from the date of purchase in this example).

[MangoMike]

Codes from my new steer Michelins. Purchased Dec. 2005

[lewpopp]

Are you asking if this tire pictured was manufactured in the 34th week of 05? The answer is yes.