Blown, when referring to a cars supercharged engine, that’s a fun time waiting to happen. When referring to a tire….well that just sent you from cruising to cussing. What is the primary cause for a tire blow out?  Before we get into that, let's talk about tires a bit first.

The tire itself carries no weight, technically it’s the air pressure inside the tire that carries the load. Tire construction and size determines how much weight a tire will carry. The structure of the tire will limit how much air you can put into a casing. You cannot fill an automobile tire and expect it to carry the load of a truck, it would be way over inflated. The tire would probably burst just due to having too much air pressure. Been there done that, it was a mower tire that had a slow leak we couldn’t find, we wanted to air it up a little extra to help find the hole, boom. I got to buy a new tire, but it didn’t leak anymore.

There are a few reasons that a tire will blow out. The number one cause is underinflation. You might think; how could an underinflated tire blow out? This is how I understand the tire experts. As I stated above the air pressure carries the weight of the load and vehicle. The air pressure also is responsible for holding the tire in the proper shape. A loaded tire when sitting on the ground is not round, it will have a flat spot at the point of contact with the ground. This flat spot, or contact patch, moves around the tire as it rolls. Moving around the tire the contact patch causes the sidewall to flex.

The flexing of the sidewall creates some of the heat along with normal friction. If you think about what a tire is built of, rubber, steel, and some composites. The rubber and the composites will flex naturally without any problem. It’s the steel belts and cords that create the heat. Try taking a length of wire coat hanger and bend it back on itself, then straighten it, bending it back and forth will eventually cause it to break; Caution, the point where it breaks will be hot enough to burn skin easily. This is what happens inside the tire when it is underinflated, the steel belts, flexing too much, break and create a weak spot in the tire that the air can then push out, and boom, the tire is coming apart. Under normal inflation, the steel will not flex enough to break.

Overloading a tire could cause catastrophic failure. Again, the air pressure carries the weight, but the construction of the tire determines how much air you can put in to carry the desired weight. Overloading the tires will cause excessive flexing of the steel, that equals heat and failure.

Potholes, curbs or other road hazards could cause tire failure, maybe not immediately, but down the road when the tire goes, you may say to yourself what just happened. There are steel cords in the casing that when driving through a pothole at 60 mph could snap some cords creating a weak spot. Weak spots can cause bulges in the sidewall and eventually a blowout. When a tire goes through a pothole, the edge of the hole creates a pinch point between the wheel and the road surface. Damage to the internal construction of the tire could be the result, avoid the potholes as much as you can safely.

Well, that's all I have to say about that. Keep the tire pressure up for the load you are carrying, this also includes not overloading. If you are under a heavier load than you are normally under, check with the tire manufacturer for recommended tire pressure. Not all loads need the same tire pressure; ideally, you should adjust tire pressure for every load, but that’s not a realistic practice. Watch out for potholes and debris, and avoid crossing or rubbing curbs if possible.

Until next time, be safe out there.

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