Everything looked fine. The tires held air, there was plenty of tread, and the tread wear was even thanks to the excellent rotation schedule of the previous owner. But this set of tires held a secret that wasn’t so obvious: they were expired. That’s why one of them came apart on the owner in the middle of south Georgia on a warm April day. Luckily the tread separation was quick and the tire still held air, which allowed the driver to make it to a nearby rest stop. The whole thing was over in an instant. A few loud “blap blap blaps” and then it was quiet. The car didn’t even shimmy, but the tire tread was last seen flying into the roadside grass.
The car owner was flabbergasted. He’d only owned the car a few months (a mid 90s Buick) but he had looked the car over meticulously before the trip. Sure he’d checked the tires, but they all had plenty of tread and were aired up to precisely 36 psi. What went wrong? Upon inspection of the failed tire the date code told the story: 1997, it was 19 years old! The tire had come apart because the rubber had deteriorated to the point that the centrifugal force exerted on the tire at highway speed ripped the tread from the carcass. The sidewalls and belting were intact, but the tread had made an exit…stage left.
So what can you do? If you are driving a car made within the last five years and have only bought new tires, you have little to worry about. Once you get past five years or if you are the second owner of the car, you need to find out the age of your tires. Tire Rack has an excellent guide on how to determine the age of a tire. If you are in the market for used tires make sure to check the age before plunking down your money.
Tires don’t have a set “expiration date” like a jug of milk, but once you pass the 5-6 year mark things start to go down hill. Exposure to sunlight, heat, and even low tire pressure can all accelerate the rate at which a tire ages. Sunlight and heat make the rubber deteriorate (rot) to the point it loses elasticity and strength. Running a tire low on air for extended amounts of time can cause the sidewalls to rip (think of how you can break a piece of metal by bending it back & forth, same idea). Low tire damage isn’t always visible, but a ring around the tire sidewall is usually a sign that a tire was run low on air for too long.
We are going to go ahead and say that if your tire has a three digit code (which means it was made before the year 2000) it should be replaced, period. Again, just because the tires LOOKS fine doesn’t mean it is fine. If you still think it is a waste to get rid of it, maybe make it into a nice planter or a swing. Don’t gamble with an old tire just to save a few bucks.