One of the biggest fears that drivers have is experiencing a blown tire while driving at highways speeds. Believe it or not, the National Highway Traffic Safety Administration (NHTSA) reported in 2003 that, of the 78,392 accidents that occurred due to a blown out tire, 414 people lost their lives while nearly 15% (10,275 individuals) suffered non-fatal injuries. In 2004, the TPS or Tire Pressure Sensor system went into effect and was introduced primarily on luxury cars as an added feature. Today, most new cars, trucks, and SUVs come equipped with TPS monitoring as a standard safety feature.
Recent data from the NHTSA indicates that the number of fatalities and non-fatal injuries, as well as the number of accidents, have decreased since the TPS has been in use. Although tire construction and early alert systems have helped reduce serious accidents due to tire blowouts, this type of emergency situation is still very possible. Having the right knowledge of how to handle a burst tire as the incident is occurring - as well as having knowledge on what you need to do to ensure your car is in working order before driving - is essential to your safety. In this article, we'll explain what causes a tire to burst suddenly, how to reduce the potential of a serious accident when you're driving a vehicle that suffers a burst tire, and what you need to have serviced or inspected after this incident occurs.
Part 1 of 4: Understanding how tires are made
The tires that provide smooth rides are considerably different than the first commercial rubber tire invented in 1888. The modern tire is made today out of a carefully balanced and scientifically researched rubber compound made specifically for a certain application. A tire made by the same company for a sports car has a completely different rubber compound than a minivan made by the same company or at the same manufacturing plant.
Beyond the core substance on the outside of the tire, today's tire is also constructed out of multiple layers of nylon cords, polyester, and steel belts as well as other textiles to provide support. The specific design and amount of layers also factors into the design and application. As such, when you drive off the showroom floor with a brand new car, you can feel confident that the tires on that vehicle were designed specifically to match its mechanical components, and most importantly, to keep you safe as you drive.
Most tires today are referred to as "radial tires." A radial tire is constructed using multiple cord plies laid at a 90 degree angle in the direction that the tire is intended to travel. Not too long ago, the tire on your vehicle was the part that touched the ground, but air that inflated the tire was provided by an inner-tube. When the tire manufacturers realized they could make a safer and more cost effective tubeless tire, they began to use this method on most production vehicles.
Some performance and off-road vehicles have a tire within a tire known as an inner liner that is included in either the construction of the tire or as an added safety measure. This type of tire does not have the 90-degree nylon cords used in radial construction, but does have the all-important inner liner for added stability and protection in case of tire failure. In the case of a tire explosion or rapid loss of air pressure, the inner liner will maintain pressure and provide stability to vehicle. This allows the driver of the vehicle to remain in control and stop the vehicle slowly, possibly avoiding a serious accident.
Part 2 of 4: What causes a tire blowout?
Whether it's for proprietary reasons or legal reasons, trying to get a tire manufacturer to disclose the exact cause of a tire malfunction is nearly impossible. However, in general, there are four primary reasons why a tire blows out suddenly: the tire was under-inflated, it was overinflated, a mechanical or material defect in the tire, or tit hit something that caused the puncture.
There are two schools of thought about proper tire inflation. Automotive engineers select a tire and a tire pressure that is best suited to driving comfort, vehicle stability and safety during the normal operation of that vehicle. Typically, the recommended air pressure is within 10% of the maximum tire pressure recommended by the tire manufacturer.
The recommended tire pressure by the automotive manufacturer is located in two places as required by US law:
The driver placard, which is located on the driver side door or on the inner door-jam has the tire size and tire recommended air pressure for front and rear tires, and the owner manual, which has this data in a tire care section inside the owner manual.
Some vehicles have this data under the hood as well so that technicians can easily review it. Low tire pressure occurs for multiple reasons:
The weather changes: The air inside your tire is similar to the air we breathe (unless the vehicle is filled with Nitrogen). Air expands and detracts as the temperature increases or decreases. If your tires were installed and filled with normal air from a compressor during a hot and sunny day, the air pressure inside the tire will decrease when the temperature drops more than 30 degrees. In fact, it's common during winter for tire pressures to drop 3 to 5 lbs. Small puncture or leak in the tire: Sometimes while driving we might run over a tack, nail, or some other sharp object that penetrates the case of the tire. When this occurs, the tire develops a very slow leak that is very difficult to find.
If the vehicle has a TPS alert sensor installed within the wheel of the vehicle, it often alerts the driver that they have a low tire, so they can have it inspected and repaired by a professional tire technician. However, sometimes the slow leak can come from non-traditional sources such as a loose valve stem core, broken valve stem seal, a bad tire bead, or rust or debris between the tire and wheel.
If a tire functions with low pressure for long periods of time, it creates additional stress and heat to build up on the sidewall and inner components of the tire. The sidewall has to flex more, which causes excess heat to build up and causes the inner layers of the tire to burn and fall apart. If the tire pressure issue is not solved quickly enough, the sidewall wears out to the point that the slightest bump could cause a rupture in the sidewall.
In this case, the rubber, nylon, and other materials that make up the inner case and sidewall of the tire burn. This is known as a "run flat" tire. You can physically check your tires and see a burn line around the entire tire located on the sidewall of the tire if you have a "run flat" tire. If you notice this condition with your tires, have them replaced immediately. To avoid "run flat" tires, it's a good idea to have your tire pressure checked once per week. You can complete this yourself very easily by following the steps below.
Step 1: Check your tire pressure in the morning. It's always best to check the tire pressure when the tires are "cold."
To check the tire pressure, simply remove the valve stem cap, press the tire pressure gauge securely on the valve stem, and read the pressure on the sliding indicator that pops out when the tire pressure is registered.
Step 2: Verify your recommended tire pressure and fill. Make sure you check the recommended tire pressure that is located on the side of the driver door or inside the owner’s manual. Fill the tire with compressed air from a service station or tire store and verify the air pressure with the same gauge you used.
Step 3: Have tire inspected for slow leak. If you are finding that your tire is going low frequently, make sure to have a tire store inspect the tire for a slow leak.
Most leaks are caused by a nail or a valve stem that is broken.
Part 3 of 4: What to do in case of a tire blowout
In any emergency situation, remaining calm is by far the best remedy for handling a tire that blows out or shreds. According to the non-profit organization B.R.A.K.E.S. (Be Responsible and Keep Everyone Safe), one of the best tools that an experienced or inexperienced driver has in case of an emergency driving situation is the correct preparedness on how to avoid accidents.
Listed below are a few important steps that you should follow in the event that you experience a blown tire while driving.
Step 1: Slowly release pressure from accelerator. As soon as you hear or feel the tire blowout, the first thing you should do is nothing.
Often driver's instinct is to slam on the brakes and quickly release pressure of the gas pedal. This is typically when the accidents occur. The right course of action is to slowly release pressure from the gas pedal (accelerator) a few seconds after you feel or notice the blown tire.
This will slow the rate of acceleration of the vehicle and keep the vehicle aligned straightly. You do NOT want to quickly release the throttle, as it could cause the vehicle's suspension to unload and create a bigger problem.
Along with making sure to release pressure of the gas pedal slowly, you need to make sure not to touch the brake pedal AT ALL INITIALLY. Doing this causes the tire and brakes to lock up, creating a hazardous driving situation.
Step 2: Make sure both hands are on the steering wheel and you are focusing straight ahead. This needs to be done at the same time you are beginning to release pressure from the accelerator pedal.
As soon as you hear that tire pop or feel it in the steering wheel, place both hands on the steering wheel (in the three and nine o'clock position). Maintain a firm grip, but DO NOT hold onto the steering wheel tight. Again, the key here is to remain calm and keep your steering wheel straight. You should also look straight ahead which will help you keep the vehicle straight.
If your vehicle begins to skid, carefully correct the steering input to counter the direction of the skid. Again, be calm and make slow and gradual corrections as overcorrecting makes the situation worse.
Step 3: Find a place to pull over. Your location at the time of the blowout determines the next few steps that you should take.
As soon as you've gained control of your vehicle and are keeping it driving straight, you need to find a place to pull over that is clear of traffic. Follow these guidelines based on your current position to pull over:
If you are driving on a single-lane road, try to pull off the side of the road when there is an opening and the space is at least two-times the width of your vehicle. You don't want to pull into a bicycle lane and risk being hit by an oncoming vehicle. Try to find a turnout or dirt area that gives you plenty of room. Your safety should be the number one priority here.
If you are driving on a multiple lane highway, you should try to pull as far over to the right as possible. Many people make the mistake of pulling into the center shoulder near the fast lane; however, this often creates a very dangerous situation not only for you and your passengers, but for roadside assistance or police officers as well.
Although you should always place an emphasis on safety, also consider practicality. If you're going to attempt to change your blown tire, make sure you pull over where you can safely jack your vehicle up.
Step 4: Gradually pull over and slowly come to a stop. Sometimes it's difficult to relax when you've just popped a tire all of the sudden.
However, once you've found a place to pull off the road, you need to do so in a slow and controlled method. Gently apply pressure to the brakes and keep a firm grip on the steering wheel. If the blown tire is on the front axle, turning and braking is exceedingly difficult. But, if you're smooth during this process, the possibility of losing control or locking up the front tires is reduced.
Step 5: Determine if you have the ability to change the tire or call roadside assistance. Put the vehicle in park or place in a forward gear for manual transmissions, and apply the parking brake.
Carefully step outside the vehicle to inspect the damage. If the blown tire is on the rear, you have a good spare tire, and you feel comfortable changing the tire, follow the instructions in your service manual or owner’s manual and complete the change.
If the tire is on the front end, this decision is a bit more complex. When a tire blows out on the front, it can cause serious damage to front end components, brakes, or steering system parts. If you have a road side assistance program (such as AAA or your insurance company) it is advised that you contact them and have the vehicle towed to your home or repair facility. Damage to the front end can cause serious safety risks if you change the front tire and attempt to drive home. Always defer to having the vehicle towed home and complete the post blown tire inspection outlined below.
Part 4 of 4: Complete a post-blown tire inspection
A blown tire is a violent situation where compressed air inside the tire explodes for multiple reasons. This sudden explosion can cause significant damage to front end components including brake pads, calipers and rotors, Front end CV joints/boots, tie rods, upper, and lower control arms and spindles, and wheel bearings and other steering related components.
It's also highly likely that the vehicle's wheel is damaged because the wheel was probably driven on during the process of slowing down and pulling over. A post blown tire inspection should be completed by a professional ASE certified mechanic to verify that it is safe to drive.
Also, before having a new tire installed on the wheel, have the tire shop check the wheel for signs of cracking (especially if it was an alloy wheel) or signs that the wheel is bent. Installing a new tire on a bent wheel is dangerous and creates balancing problems.
If you've recently experienced a blown tire and need to hire a mechanic to complete a suspension inspection to ensure nothing else on your vehicle is damaged, have one of YourMechanic’s certified technicians come to your home or business and take a look.