Conventional wisdom tells us that tire thread is an acceptable proxy for determining the age of a tire. However, this does not take into account the ongoing deterioration that occurs within the tire. This deterioration is ultimately the true gauge of how “old” your tires are. This is especially true for those who do not drive frequently. If you were to drive the 10,000-20,000 miles annually that most drivers do, your thread would wear out well before the rubber in the tire loses its integrity. But consider the fact that a car that gets driven only 5,000 miles a year will not show its true age, and these tires present a safety hazard regardless of its tread.
So what exactly is happening? According to experts, aging tires are much like old rubber bands that appear to look new but when stretched- show signs of cracks and degradation. In the case of worn-out tires, the cracks happen slowly and progressively become worse. At a certain point, they will cause the tread to separate from the tire. No tire is immune from this phenomenon, although tires that are rated for high mileage will typically have chemicals added to the rubber during the manufacturing process.
You may be wondering how long tires should last. Since there are no federal guidelines that dictate when tires should be replaced, it’s up to the manufacturers to suggest an appropriate replacement timeline. Having said that, there are various factors that affect the lifespan of a tire.
First up is heat. Heat is known to speed up the rate of chemical reactions, hence it only makes sense that heat -think warmer climates- will hasten the rate at which tires degrade. Another factor that plays a role for tires is the way in which it’s stored, think spare tires. Even a spare tire which is sitting idly in a garage will age over time, although slower than a spare left in the trunk, where it may get exposed to a great amount of heat. Finally, we must also consider the conditions in which tires are kept in. Are they kept inflated? Are they free from damage, or past damage that has been patched? How about tire rotations and other preventative maintenance? Routine care is the most effective strategy to prolong the life of your tires.
Now let’s discuss the steps in which we determine the tire’s age. Quite simply, you will have to determine your tire’s date of birth. We do this by examining a tire’s sidewall. You should be able to make out a four-digit code- other known as the DOT number. It will be a four-digit code where the last two numbers represent the year it was manufactured, and the first two numbers represent the week of the year. You may have to check the inner wall of the tire if you don’t find it on the outside portion. Next, you will want to physically inspect your tire for signs of aging. This will show up in the form of treat distortion, and cracks in the sidewall. If you notice any irregularities, it is advised to have your tires replaced immediately.