Much like a good beer, all tires are stamped with a Born On Date at time of manufacturing. Also like beer, tires have an expected shelf life and they both age very differently on an uncontrolled shelf versus in a temperature-controlled environment. When the new rubber you ordered from www.ChapMoto.com tire order arrives to your door step, just how fresh are those tires?
The tire’s born-on-date, commonly known as a Date Code, is a standardized 4 digit number indicating the Week of and the Year of tire manufacture. In the case of the Shinko tire in this video, the tire was manufactured on Week 38 of 2016. This standardization was created and set into effect in the year 2000.
If you have a bike older than a 2000 model, still sitting on its original tires, the code will contain the same information, but it will read a little differently.
The last 3 numbers you see here indicate that this tire was manufactured the 40th Week of the 8th year of that decade. While this previous Tire Identification Number format identified that a tire was built in the 8th year of a decade, there was no universal identifier that confirmed in which decade that production took place. You can see why DOT decided to make the designation a bit more concrete.
Beginning in the year 2000, the U.S. Department of Transportation (DOT) and the National Highway Traffic Safety Administration (NHTSA) require that tire Identification Numbers be a combination of the letters DOT followed by eight to thirteen letters and or numbers which identify manufacturer location, tire size, manufacturer’s code along with Week and Year the tire was produced.
Now, how long do tires last? As with beer, a tire’s shelf life differs greatly depending on how it is stored. Left out in the sun and the elements, a beer might last a week and a tire is lucky to last a year without showing signs it is in need of replacement. On a pantry or warehouse shelf subject to temperature changes, a beer is good for several months and a tire for several years. Now, a beer stored in a refrigerator can stay fresh for years. Similarly, a tire stored in climate-controlled warehouse can stay fresh for up to 6 years.
Here is what the top manufactures say:
Michelin: All Michelin tires come with a limited warranty which covers defects in workmanship and materials for the life of the useable tread or 6 years from purchase date, whichever comes first. ** Note: Hold onto your receipt! If your tire born on date is 2 years old… and you misplace your receipt your warranty will revert back to the date code on the tire, not purchase date.
Bridgestone: If, before wearing down to 1/32 inch (0.8 mm) of remaining original tread depth (i.e., worn down to the top of the built-in indicators in the tread grooves), and within 4 years from the date of purchase (proof of purchase required; without proof of purchase, then 4 years from the date of manufacture—referenced by the last four digits of the DOT number), for any reason other than those excluded in the section entitled “What This Limited Warranty Does Not Cover,” any eligible tire becomes unusable for any reason within the manufacturer’s control, such tire will be replaced with an equivalent new Bridgestone tire on the basis set forth in this Limited Warranty.
Metzeler: Motorcycle tires are covered for the life of the tire, 4 years from the manufacturer Date Code or until the tread depth reaches 1/32”.
Written by Kyle Bradshaw