On average, only a square foot of rubber tread connects your car to the road beneath it. Tires are important in nearly every dynamic motion your car makes. New rubber helps acceleration, handling and braking — but even a perfectly fine looking tire can be dangerous. Because of this, replacing your tires can be one of the biggest safety upgrades you can make on any car — even if they aren’t worn.
As the rubber of the tire gets older, especially when exposed to heat and sunlight, it will chemically change and harden. This can lead to one of two problems. For one, the tire has less grip on the road as the harder, older rubber is less sticky than new rubber. A turn that used to be no problem suddenly could have you skidding off the road. Additionally, the age of the rubber could just cause the tire to fail, leading to a blowout. A rubber band illustrates this point well. A brand-new rubber band can stretch with no problem and return to shape. In comparison, old rubber bands are often cracked and will snap easily. One of the most infamous examples of this is the crash of "The Fast and the Furious" actor Paul Walker, who died as a passenger in a Porsche driven by a friend.
While investigations found the speed of the Porsche was in excess of the speed limit, the speed may not have been in excess of what the car could typically handle. The issue? Although the tires had good tread remaining, they were over nine years old. The hardened rubber on these 9-year-old tires was undoubtedly a factor that caused the car to skid off the road into a tree.
Of course, this isn’t the only example; many trailer tire and motor home blowouts on the interstate happen for much the same reason. Because these tires don’t get worn in the same way, the tread looks fine, but the tires fail anyway.
So, how do you tell the age of your tire? It’s simple! If you look on either side of any tire on your vehicle, you will find what is called a DOT number. It starts, unsurprisingly, with "DOT." It then continues with a series of letters and numbers anywhere from eight to 12 characters long. No matter how many characters there are, the last four will be what you’re looking for. The first two give the week the tires were made, and the second two give the year. For example, "4010" means the tire was built in the 40th week of 2010 — and that means it needs to be replaced. If you look at the headline image, you will see a DOT code ending in 2718. This tire on my Lexus GX was manufactured during the 27th week of 2018.
If you still doubt my safety warning, search "old tires causing accidents" and you will find that the extent of this problem goes on and on. I hope everyone that reads this realizes the importance of replacing old tires, no matter how much tread is left. Buying new tires may be pricey, but it’s worth saving your car — and possibly your life.
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