How Do Car Tires Hold Air? (Explained)

Let’s dive deep into how a car tire can hold air.

We start by looking at the different parts of the tire to better understand how it all works together.

Learning More About The Different Parts of a Tire

The tire category type may vary depending on the vehicle in question but each tire is made up of the same general components. The more a motorist learns about these components, the easier it is to learn about a tire’s ability to hold air.

The short answer is that the beads, inner liner and bead filler will work together to hold the air inside the tire.

It still behooves a motorist to learn more about the different parts of each tire.

Inner Liner

The inner liner plays a key role in holding the air inside of a tire because it is a rubber compound that has been bonded to the inside of the cord body. This allows the tire to retain air under pressure.

The inner liner functions in the same manner as an inner tube and there is no cord reinforcement to speak of.

The days of car tires having inner tubes inside of them have long since come to an end. Instead, the beads, bead filler, and inner liner work together as a means of holding air inside of the tire.


In order to truly understand the manner in which these items come together to hold air inside of a car tire, it is important to start from the inside out.

The tire beads are responsible for ensuring that the tire remains attached to the rim, at the wheel’s outer edge.

These beads are made of high tensile steel wires that have been copper, brass or bronze plated.

When the wheel is rolling, the tire beads are responsible for making sure that the wheel does not slide out of place.

Bead Filler

Within the beads of the tire, there is a rubber compound. This is what is known as bead filler. The lower sidewall and bead area are provided with the necessary stability.

The tire performance characteristics are determined by the stiffness and density of the tire’s bead filler.

Radial Cord Body

The tire’s strength is derived from the radial cord body. The radial cord body also transfers cornering forces from the tread to the wheel. Body plies make up the cord body, which are also known as rubber-coated plastic cords.

These plies are typically made of nylon, rayon or polyester. In most instances, polyester is used.


The sidewall consists of the area that extends from the bead to the tread. Also known as the side of the tire, the sidewall serves as a protective covering for the body of the cord.

If the motorist needs any additional information about their tire, it is going to be found on the sidewall.

Speed rating, tire size and load index are among the information included. The rubber compounds that are designed for sidewalls have been specially formulated to resist the damages caused by snags and cuts.

The Tread

tire grip

Of course, it should go without saying that the tread on the tire is one of the most crucial aspects. Since this is the portion of the tire that comes into contact with the road’s surface the most often, it is easy to see why there are so many options to choose from.

In addition to wear, traction, handling, fuel economy, and resistance, there are other characteristics of the tire that have to be taken into account.

For starters, those who reside in areas with more wintry conditions to contend with cannot underestimate the importance of all-season tires.

Tires with circumferential tread grooves are the best choice in these instances. Thanks to the grooves that these tires contain, water is able to pass through and stay off the tread. Meanwhile, there are other all-season tires that are designed with high-speed emergency usage in mind.

They will come with an asymmetrical tread pattern.

In addition to these tread patterns, there are also sizable tread block elements on the tire’s outside shoulder.

Those elements are designed to support dry performance, as the inner shoulder is made up of a larger number of smaller tread elements that improve the tire’s ability to handle snow traction and wet, wintry conditions.

So, How Do Car Tires Hold Air?

The tire hold air by the pressure between the rim and the tire. There are no holes or cracks for the air to slip though. This also means that we don’t have a tube in the tires. They are simply help together by the pressure of the air inside the tires.

Let’s take a closer look at some of the most commonly asked questions about car tires and their ability to hold air:

How Many Pounds of Air Should Be In The Car Tire?

When the tires are cold, most passenger cars will recommend using 32 psi to 35 psi of air in the tires of a passenger car.

The pressure needs to be checked when the tires are cold because the tires will create friction when they are rolling along the street. This creates a higher level of air pressure and increases the temperature in the process.

Should All 4 Tires Be Changed At The Same Time?

The full set of tires should always be replaced, since a refusal to do so can cause serious damage to the system of the vehicle. 

In certain circumstances, it is best to only change one or two.

This is especially important if the difference in tread for each tire is particularly pronounced.

How Do New Tires End Up Wearing Out So Quickly?

This is one of the more common queries that takes place and there is a very simple answer for this. The tires that come with a new car are not actually manufactured by one of the major companies.

The manufacturer of the car is responsible for them.

In most instances, the rubber that they use is quite soft, leading to faster wear outs.

When Is It Time For New Tires?

When it comes to replacing tires, this is something that we do not always handle in a timely manner. Instead, we often wait until our hand is forced and there is no choice but to get the tires replaced.

Fortunately, there are a few telltale signs that it is time for new tires that any motorist can keep an eye out for:

Cracks and Gouges

Once a tire begins to deflate, there are bulges at the side. It won’t be long before cracks and gouges start to show themselves. If any of these imperfections start to become more noticeable, it is time to take the vehicle to the dealer.

Let them take a look before things get too far out of hand.

Testing The Wear

The good old-fashioned penny test will certainly come in handy here. Put a penny into the tread of the tire and make sure that Lincoln’s head is facing downward. If you are able to see the top of Lincoln’s head, this means that the tread is too low.

Be sure to replace the tire immediately.

Many modern tires also come with wear bars. If the tires have been worn down to these bars, this means that the motorist is overdue for a replacement.

Tire Pressure Levels

The level of tire pressure also goes a long way towards telling the story.

The average tire deflates at a rate of one pound per square inch each month. The tires are not going to wear down within one month’s time but it still behooves motorists to be proactive instead of reactive.

Changes In Temperature

When extreme cold arrives, the pressure in the tires will drop accordingly. Meanwhile, summertime brings a whole new challenge.

This is when drivers are forced to contend with excessive heat buildup inside of the tire.

Tires must be properly inflated during each time of year. Tires that are not properly inflated are going to wear out much, much faster than their properly inflated counterparts.

Listen For Vibrations

Thumping and vibration while driving are especially problematic. Does the thumping feel like it is coming from the back seat? That means that the tires could be out of balance.

If the vibration is taking place in the steering wheel, this typically means that there is a suspension issue. Once the ride is not as smooth as it should be, it is time to head to the dealer.

Last but certainly not least, the motorist must maintain awareness of the best types of tires for their personal driving situation.

What Tires Are Most Commonly Chosen and Why?

All season tires are the most commonly chosen in the modern day. They provide the motorist with the traction that they need, all year round.

For most models, the tread range is going to fall anywhere between 60,000 to 100,000 miles.

What Are All Season Tires?

In order to understand the importance of all season tires, it is crucial to know why they are so effective. Thanks to their tread patterns and rubber compounds, they are able to be utilized in a wide range of conditons.

This keeps the driver from having to swap out their tires for new ones every time that they look up.

These tires are even designed with the ability to handle light snow in mind, making them a no-brainer for most drivers.

What About All Weather Tires?

There are often debates as to whether it is better to utilize all-weather tires or all-season tires. As with most choices of this nature, it will all depend on the weather conditions at hand.

Those who reside in warm, dry or mild conditions are likely able to use all-season tires.

Meanwhile, anyone who resides in a more wintry climate will want to choose all-weather tires. When slush, snowfall and heavy rains take place, all-weather tires are able to handle these conditions far more easily. Don’t make the mistake of relying on all-season tires in these instances.

Do Dealerships Ever Overly Inflate Tires?

Before we take off, it is time to shatter one very common misconception that has been allowed to circulate for far too long. No, dealerships are not responsible for the over-inflation of tires.

The tires are inflated to the proper specifications.

So why does this misconception still linger? The tires will often expand once the motorist hits the roadway. Since the shop is cool and the roads are warm, this is a natural occurrence.

This is not the dealership’s fault and is 100 percent normal.


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