What causes a tire to blow out?

tires
Written by Ken Coul

Tires blow out; it’s a fact. Some of us experience it first hand when driving, others see it on their cars before or after they park and some just read or hear about it.

Tires are one of the most important parts of the vehicle, in fact, they are the only part of the vehicle that touches the ground, and as such, are the only part of the vehicle that needs controlling for accelerating, direction and braking. Which means that without tires you don’t go anywhere, and with bad tires, you end up in the emergency ward or even worse, the morgue.

What is really bad about bad tires is the effect they have on innocent bystanders, many a news item has been posted telling us of tire blowouts that caused a car to veer into a pedestrian or another vehicle, ending up in injury and death.

So, what causes a tire to blow out how can we prevent it from happening? To answer this, we must understand what a car tire is made of.

Car Tires

A tire is made up of several parts: the tread, bead, sidewall, shoulder, and ply.

Tread

The tread is the part that sits on the road surface; this is made of a thick rubber compound (styrene-butadiene copolymer) that is suited for specific surfaces. So different surfaces and vehicles will use different tread materials as well as tread designs.

Tread patterns come in a variety of shapes and size, and the pattern these are characterized by geometrical shapes termed grooves, lugs, voids, and sipes.

Grooves are used to channel away water and run circumferentially around the tire. The Lugs are the part that sits on the road surface, and the voids are the spaces between the various lugs. Sipes are the slits that cut across the tire and help water escape from the grooves.

tire

Wear bar

These are indicators that appear when the tread has worn down and show that the tire is now too worn to be used.

Bead

The tire beads a made of reinforced steel and sits tightly against the two rims that ensure the tubeless tire holds air and also to prevent the tire from shifting circumferentially as the wheel rotates. These can be made of steel, nylon or Kevlar.

Sidewall

This is a rubber compound that bridges the tread to bead. This is the part that holds the air pressure and transmits the torque from the by the drive axle to the tread that makes the traction. This part of the tire does not support the weight of the vehicle.

Shoulder

The shoulder is the transition between the tread to the sidewall.

Ply

Plies are layered inextensible cords embedded in the rubber that stop the tire from stretching. Plies are the main category definition for tires. These are also made of steel, nylon, and Kevlar as well as synthetic fibers.

Causes for Blowout

The three main causes of blowouts are:

  1. Worn Treads
  2. Dry Treads (Cracks)
  3. Foreign Objects that Puncture the Tire
  4. Melting

Worn Treads

When a tire is not replaced and allowed to wear away, the rubber surface coating no longer protects the integrity of the inner components. These can be easily punctured, cracked or ruptured due to the internal pressure and external forces. A worn tire will blow-out 100% of the time. Another side effect of a worn tread is your braking distance; you don’t have one, you will hit the car or person in front of you if you brake with a worn tire, especially in the rain. You will also hydroplane on wet surfaces with worn tires, guaranteed.

Dry Treads (Cracks)

When tires get old they dry out, even if not worn, old tires like most materials will start to disintegrate. An old tire will have to telltale signs of cracks, and these cracks can reach as far down as the liner, which means that the internal pressure can suddenly cause a rupture in the area of the crack leading to a blowout.

Foreign Objects

Foreign Objects such as nails, certain ceramics and metals can puncture the thick and safe rubber tread causing the internal pressure to leak out and blow suddenly when driving. When the car is standing still, the air will escape slowly, rather than blow out.

Melting Tires

Tires heat up when you drive, the friction of the tread to the surface causes the tire to heat a lot. This friction is due to lower tire pressure that leads the tire to flex beyond its specifications. This then causes the internal fabric and steel cords to separate from the rubber.

Prevention

Checking Pressure

Check your tire pressure once a month with a tire pressure monitoring system. This is a mandatory preventative maintenance issue. If you visit your local gas station, take the time to check your tire pressure. If its low, fill them up. Keeping your tires at the right pressure will assure that they do not wear down quickly or melt, leading to a blowout.

Check your spare tire pressure once in a while too, perhaps every quarter. (three months) You don’t want to end up changing a blow out finding your spare is flat. Also, tire sealant might help you too.

Checking Integrity

At least once a month, go over your tires surface. Check for cracks or telltale signs such as bubbles for melting issues. Also look at the tread and how to work it is. Don’t wait till the last minute, if you tire a suspicious appearance, take it to a tire specialist and get it fixed or replaced.

Balancing and Aligning

Visit your tire specialist at least once every half a year and get your tires aligned and balanced. You don’t need to change the tires; you just get them recalibrated for better performance. This will increase their lifespan and reduce wear.

Load Bearing Limit

Do not exceed the manufacturer’s weight bearing limits for your vehicle. These limits are based on the tires and the pressures used. Even if you pimp up our ride, don’t think that having a higher vehicle and larger tires will allow you to carry more weight.  One of the biggest mistakes made is overloading a vehicle; this leads to faster wear on the tread. This is also an issue with braking, the heavier the car, the harder the impact of braking on the tire tread and the faster you wear them out. Also, braking with a heavier load on wet surfaces will lead to longer braking distances as well as hydroplaning even on good tires. Also, use tire deflators to keep your tires from blowing up.

Avoid Overheating

The only way you can avoid overheating is by driving carefully. If you are a formula-1 racer, then you expect those smoking hot tires. If you are driving to work, or working for Uber, or just driving your family to lunch, do not become a speed racer. Poor road conditions combined with fast driving leads to work tires, blowouts, and accidents.

Conclusions

Tires might seem rough and bulky, but they are precision parts and need more caring for than you consider. My final tip is to follow the tips I provided here; they will give you a longer tire life, safer driving experiences and save you money and a lot of legal hassle.