Shopping for a Used Car? Keep in Mind That Tires Age, and Not Like Fine Wine

Say you’re in the market for a used car, and you’ve come across a gem of a 2005 model for sale. It’s clear that, with low miles and in pristine condition, the car was rarely driven and has been well cared for. There’s even a lot of tread left on the tires. Naturally, you’re interested in the purchase. Then you check out the sidewalls of the tires and find out they’re from 2005, too. Those tires are likely the original rubber. No matter how good a condition the tires appear to be in, they’ve got to go, according to tiremakers, auto companies, and safety advocates alike.

There is some fluidity as to when tires go bad by age, because the reasons for their degradation are numerous. But 12-year-old tires would exceed all age limits in the world of rubber radials. Most tiremakers say tires should be inspected after six years and replaced after 10, and several automakers recommend replacing tires after six years of use. Tires get weaker with age because of heat, oxidation, humidity, and other external factors, such as where they’re driven or stored. Even tires that are never put on the wheels of a car age as they sit. Let’s face it, tires are not the same as fine wine.

Rather, aging tires can be thought of as similar to rubber bands, said Sean Kane, founder and president of Safety Research & Strategies. If you take an old rubber band and stretch it, you can see cracks, and if you keep stretching it, it will break. The risk you run by using an aged tire is tread separation, and then, obviously, possible loss of control of the vehicle you’re driving.

A tire’s age can be checked by looking at the U.S. Department of Transportation’s Tire Identification Number (TIN) on the sidewall. It is not as straightforward as it should be, said Kane; it’s geared more for tracking recalls than to use by consumers to track expiration dates.Note those four digits at the end. They tell us that the tire was made in the 26th week of the year 2013, so NHTSA’s fictitious tire here is about four years old. This four-digit date setup only goes back to 2000. Before that, the letters would include just three numbers, with the first two digits indicating the month and just the last number denoting the decade in which the tire was made. That means that if the last number in the three-digit code is an 8, the tire could have been made in 1998, 1988, or 1978. But if you have tires older than the year 2000, they should be replaced anyway. The complete TIN is federally required to be on the tire, but Kane notes that the entirety of the code only has to be on one side, so you may have to get under a vehicle with a flashlight to find it.

Date of birth aside, another sign to look for in aged tires is weather checking, also known as dry rot. This can appear as small cracks on the sides or in the treads of the tires, light discoloration, or carcass deformation, which means the tire is becoming misshaped. Used tires that come with a vehicle can also look perfectly fine, especially if they’re stored in ideal conditions, even if they’re nearing or well beyond their six-year mark. But looks can be deceiving, according to Bob Toth, director of industry relations for Goodyear in North America. “If it looks pretty good, that’s a positive sign, but even then you don’t know if it was repaired or properly repaired,” Toth said. There could be plugs from when the tire was repaired, or they just generally could have been poorly maintained by a previous owner.

“Used tires are a risky bargain no matter what, because you don’t know who had them [before],” said Dan Zielinski, a spokesman for the U.S. Tire Manufacturers Association (USTMA). This is also why groups such as the USTMA have been trying to put restrictions on the sale of used tires. Such an effort was recently successful in New Jersey, where a new law imposes a fine on a business that sells tires that have had improper repairs or show unsafe conditions, such as worn-out treads or other visible damage. Obviously, the USTMA recommends buying new tires to avoid buying something that ages less like a fine wine and more like yogurt behind a radiator.

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