Do Street Tires Age Out?
On the side of a DOT tire, there are a whole bunch of markings.? They must mean something.? They do. And we will often examine them as part of our service inspection, and comment to our customers that their tires are “aging out”.? Then we get a queer look.? They think we are just fishing for more sales.? But, we are not.? We are reporting the facts and reporting something that is a significant safety issue.
If you buy a new tire….is it really “NEW”?? Not always.? It may have been produced more than a year ago, and has been sitting in a warehouse, until purchased for or by you.? So, back to the question, do tires age out? Well…lets look at the logic. Tires are made of rubber.? It is recommended that you replace your engine serpentine belts and hoses at least every five years.? Why?? Because rubber breaks down over time.? We also know that heat affects rubber greatly, and can accelerate the deterioration of rubber.? Next, tire manufacturers warrant their tires (not from wear, but from defects).? How long is the normal tire warranty?? Four years…hmm, wonder why only four years.? Why not for the life of the tire, why not for as long as the customer uses them, or at least a period of 10 years.
From racing, we know the affects of heat on tires as well.? We track and mark every “heat cycle” a racing tire consumes, and normally, full racing tires “heat cycle” out at about 10 – 12 cycles.? DOT track tires may be able to go as high as over 20 heat cycles, but they too heat cycle out.? This is often less than a year in age.
This issue of age of the tire is important enough that the Consumer Affairs Department petitioned the NHTSA (National Highway and Transportation Safety Association) to require all tires to have easily readable dates of manufacture.?? The SRS has been tracking the many fatalities and serious injuries that have been associated with age-related tire tread separations.? In many of these cases, the tires were often the unused spare tires and showed no signs of degradation.? The net….tires do age out, even if they look like they have plenty of tread, or have lots of wear remaining, and the issue is not the acceleration of the wear, but the degradation of the tire, and possible separation of the tire, causing a tire failure or blow out.? That is not what you want to happen when driving your car, and you absolutely need to be aware of the age of your tire.? So, how do you know?? The markings on the side of the tire tell all….
For tires made after the year 2000, the last four digits of the DOT markings indicate the date of manufacture of the tire (example, in the image the last four digits are 0305, which means it was made in the 3rd week of the year 2005.
The full breakdown of this data (DOT MA L9 ABC 0305) means the following:
DOT markings (so you can distinguish from all the other markings on the tire)
MA = MFR and plant location code
L9 = Tire size code
ABC = options code used by the manufacturer
0305 = 3rd week of 2005 was when the tire was manufactured
So, you need to trust your tires, you want to ensure the safety for your car and your family….take a look at the age of the tire.? Most tire shops will agree, 6-7 years is the normal “safe” limit of the age of a street tire.
Check out the age of your tires (including the spare), and talk to us if you have any questions.
BRracing – ensuring the safety of our customers.