How Old Is Too Old For Your Tires?

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Age is an inevitable part of life and the same rings true for the numerous parts that make up your vehicle. But while your car's wheels can soldier on for years on end, the same can't be said about the rubber bits wrapped around them.

Your car tires are designed to last for only a few years. However, most people are so focused on wear bars as an indication of tire life that other signs of aging are typically ignored. Here's what you need to know about old tires, the inherent dangers associated with them and what you can do to keep your vehicle safe.

The Dangers of Aging Tires

As rubber ages, it deteriorates due to several different chemical and climatic effects. Exposure to direct sunlight, heat, mechanical fatigue and abrasion can do a number on exposed rubber, making it more brittle and prone to cracking than when new. That explains why a rubber band left on a window sill for days on end shows cracks once you try to stretch it. In some cases, it might even break apart on the first pull.

When tires age, they start exhibiting signs of "dry rot" — a condition where cracks form throughout the tire. These cracks can be easily seen on the sidewall and near the top of the tread sections. If left to its own devices, the tire becomes so brittle that it allows the steel belt within to separate from the rest of the tire. This usually happens during a "blowout," where high speeds and exposure to intense heat and friction causes the tire to violently unravel itself.

How Long Are Tires Supposed to Last?

There are no specific guidelines governing how long tires should last, so the answer to that question depends on the tire manufacturer's own recommendations. According to the National Highway Traffic Safety Administration (NHTSA), most manufacturers recommend replacing your tires after six to 10 years of use, no matter how many miles you've driven.

Keep in mind that there are a variety of factors that could greatly affect how fast a tire ages. Tires that sit unmounted in a garage or warehouse will age much slower than one that's mounted on a wheel and put into service on a vehicle. Curbs, rough roads, improper inflation and exposure to direct sunlight can all shorten a tire's service life.

If you see signs of dry rot on a tire, feel strange vibrations that can be pinpointed to the tires or see distortions in the tread, then you may want to change it sooner rather than later. Leaving an old tire on your car could put you at risk of a highly dangerous blowout.

Determining Your Tire's Age

If you want to know how old your car's tires are, simply look for the DOT Tire Identification Number (TIN) found on the sidewall. You'll want to look for the last four digits of the TIN, as these digits show the week and year the tire was manufactured. For example, "2613" means the tire was manufactured on the 26th week of 2013.

While most new tires will have this information on the "inner" (facing towards the vehicle's suspension components) and "outer" (facing you) sides of the sidewall, some older tires may have this info only on one side. Some tires may even have three-digit identifiers, with the first two digits denoting the week and only one digit denoting the year.

When buying new tires, don't forget to check the date located on the sidewall. It's not unusual for "brand-new" tires to spend months or even years on the shelf before being pressed into service.

Your tires are your car's only link between it and the road, so it only makes sense to make sure they're in excellent shape.

11 May 2015