There's been a lot of press attention recently to accidents supposedly caused by over-age tires, but some of these reports would have you think that many tire failures would be eliminated by creating regulations on how long a tire can be legally sold.
The truth is that most tire failures, even of recently made tires, are caused by certain conditions which have nothing to do with age. Let's review these.
The largest cause of tire failure is improper inflation: specifically under-inflation. When a tire is under inflated it flexes more, which creates heat. This heat softens the rubber, weakens the tire and increases the temperature of the air in it, which increases the tire's pressure. Now you have a weaker tire, which is over inflated and boom! The tire explodes. This can happen to a new tire as well as an old one.
When do you check your tire pressure?. When the tire is cold!
Too much weight. Each tire is designed to carry only so much weight. If you are using a tire on a vehicle different from they kind it was designed to be used on, you may be subjecting it to excessive weight.
If you have a trailer, or a cargo vehicle and add weight above that which the tire is made to support, again you have a potential problem. Adding weight to a tire, is in effect, the same as lowering the tire's pressure. You've likely seen heavily loaded vehicles where the tires seem to bulge out. These tires are being flexed much more, just as an under-inflated tire.
Even if an under inflated tire or an overloaded tire doesn't blow out at the moment, that doesn't mean that there's no damage done to the tire. In fact, if a tire which has been subjected to this kind of use even for a few minutes or a short trip, were to be unmounted and inspected, there may be evidence of damage in the form of ground-up rubber residue inside the tire as a result of being driven in such a condition.
A 3rd major reason tires fail is damage done to the tire that you can´t see at the time of the damage. We've just described one situation above. Here's another: have you ever watched a trailer being backed into a parking slot? If you look you will see that the tire will squirm, twist and all but come off of the rim. This is causing damage you can't see but it is weakening the internal structure of the tire.
A 4th reason is an abused tire. This could be a tire that hits a curb, a speed bump at a high speed, or big rocks or pot holes. If this impact is on the inside of the wheel, it too, may be another "unseen" damage. Sometimes misalignment can cause tread damage, but it is very easy to see miss-worn tread to identify the cause and in any case, this is not normally the cause of complete failure, but rather just wearing-out faster than necessary.
A 5th reason is a tire with manufacturing or material defects. This is most likely to happen with unreliable brands that are made to be sold cheaply. The reason they can be sold cheaply is because they cost less to make, either through using cheaper, less resistant materials, through skimping on inspection and quality controls.
An example of one reader: He installed four SuperStone Tradial Track LT235/85R16 tires from Sam´s Club on a Ford F-350 Dually loaded with a 10.5 ft. Silver Streak Camper. All weights were way below maximum allowable for both the truck and tires and over two years he drove only about 3,700 miles. The truck was parked and the tires covered. When he planned to take it on a trip when he pulled the cover off one of the tires the tread was blown open at the top. This had happened while the vehicle was parked!
None of the above is intended to say that tires don't age, they do, but just like people, tires don't become useless, (or dangerous) just because they pass a certain date. Indeed, most failed tires are "young" tires which have suffered damages or conditions such as the ones we've just described and if older tires are exposed to the same tortures they too are likely to fail from these.
Inspect your tires regularly. (Register for Tire Chek to get a monthly email reminder) and have a professional look them over as often as you can.
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