How Old Are Your Tires?
Written by Dave McCracken; Monday June 7, 2010 Share
One vehicle maintenance item that can easily be overlooked is tire degradation. Studies show that under or overinflated tires increase the potential for blowouts which could result in a serious accident due to lost control of the vehicle. I have to wonder how the age of tires factors in contributing to the some of these accidents.
Recently we had a customer’s 1996 Dodge Neon towed in with the left front tire flat. I inflated the tire before moving the vehicle into the shop for servicing to avoid potential damage to the tire. After a visual inspection of the tire for the cause, I removed it and placed it in a tank of water to check for the leak. I found nothing wrong with the tire and further servicing of the vehicle determined the other 3 tires were significantly below the manufactures specified air pressure. There was approximately 41,000 miles showing on the odometer, indicating the car doesn’t get driven much. All of the tires had acceptable tread depth and showed no visual signs of external fatigue.
The owner picked up the car the next day with all tires still properly inflated. Two days later, the customer drove the car from Claymont to the New Castle area and upon their return trip home via I-95; the left front tire blew out. Fortunately the owner had experience in handling such an occurrence and avoided any further distress besides a greatly increased heart rate.
I examined the tire closely to determine what caused the tire to fail. The tire tread had completely separated from the casing and there were no signs of any puncture or impact that may have caused the failure. Somewhat puzzled in my search for the answer, I checked the date of manufacture code to determine the age of the tire. I found the tire was manufactured the same year as the vehicle, making it 14 years old. I then checked the other tires and found that the right front tire was also dated 1996, the right rear tire had been replaced some time in 1997 and the left rear in 2001. Ultimately, I recommended that we replace all 4 tires and the customer agreed.
UV rays, ozone, moisture and temperature are a few factors contributing to tire degradation. Driving on an under or overinflated tire will accelerate this process. The Federal government has mandated that all new cars have a Tire Pressure Monitoring System in an attempt to reduce the likelihood of driving on improperly inflated tires. Since the Firestone fiasco in 2000, there has been a lot of discussion on setting a standard for the useful life of a tire. My research has resulted in the recommended life of a tire placed in service at 6-8 years from the date of manufacture.
If you drive an average of 12,000 to 15,000 miles per year, the concern over tire degradation is minimal since the tires will typically wear out before nature’s effects take hold. One exception to this would apply to tires that were manufactured and have been in stock for a long period of time. So you can not always rely on the age of the tires based on when they were installed on the vehicle.
The date code is either a 3 or 4 digit number following the DOT number stamped on one side of the tire near the bead of the tire which is closest to the wheel. The first 2 numbers refer to the week of manufacture and the last one or 2 designate the year. Three digit codes indicate the tire was manufactured prior to the year 2000 and should obviously be replaced.