Why Are Tires Important?

It is necessary that consumers understand why tires are so important. Tires are a vehicle's only contact with the road. Even the brawniest engine, strongest brakes, or most advanced antiskid system, is at the mercy of the tire's grip on the road. Every move a driver makes with the steering wheel or brake or gas pedal is transmitted to the road through the four notepad-sized contact patches of the tires.

Since a vehicle doesn't have the ability to change tires like a person changes shoes, consumers must select a tire that will work year 'round and in every conceivable driving situation. You wouldn't wear high heels to go hiking, and you wouldn't wear ski boots to dance a ballet. However, consumers often ask their cars' tires to do many things, and many times a vehicle's tires aren't suited to the task.

Selecting the right tires for your driving needs is as important as selecting the right vehicle. Tires that are worn won't be able to displace enough water to prevent hydroplaning. Performance tires won't be able to get much grip in snow. All-season tires can't manage the heat creased in high-speed driving. Passenger-car tires might not be able to carry the heavy load found in a contractor's pickup.

But before consumers can select the right tire, they have to understand a little tire technology first.

What is a Tire?

Simply put, a tire is a flexible container of compressed air. In reality, a tire's duties are many. It supports a vehicle's load, it propels a vehicle--forward, backward, and side-to-side. It stops a vehicle. Finally, it also cushions the load from road imperfections.

Today's tires comprise between 19-25 different components. Contrary to popular opinion, tires are built from the inside out rather than the outside in. The heart of every tire is an inner liner. Its job is to give the tire shape and hold in the air. Wrapped around the inner liner are fabric belts. Fastened to the bottom of the fabric belts is the bead, which holds the tire to the wheel.

On top of the fabric belts are steel belts. These belts have two jobs. One is to give the tire stability, and the other is to make the tread pattern as flat as possible. (A flatter tread means more contact with the road.) On top of the belts is the tread of the tire. There are different tread patterns for different types of tires. Finally, on the side of the tire, appropriately enough, is the sidewall. This is what gives a tire its stiffness or ride characteristics. A taller/softer sidewall will absorb more bumps, while a shorter/stiffer sidewall will provide better cornering ability and sharper steering response.

Q: Why should I install two new tires on the rear axle of my front-wheel-drive vehicle?

A: Because a vehicle with brand-new tires on the front axle and worn tires on the rear has a greater tendency to lose control when turning in wet or slippery conditions. While the new tires on the front may "hug the turn," the worn tires on the rear may slide out and "fishtail." This condition is known as oversteer, and it has been known to cause serious and fatal accidents on front-wheel-drive vehicles with two new tires on the front axle and two worn tires on the rear.


Q: Can I install two snow tires on the front axle without installing them on the rear?

A: No. If winter/snow tires are installed on the front axle of any vehicle, they must also be installed on the rear. The difference in traction qualities may result in adverse handling characteristics, which can lead to loss of vehicle control. Therefore, in order to maintain performance and stability, it is recommended that winter/snow tires be installed on all four wheel positions on front-wheeldrive vehicles.


Q: How often should I check the air in my tires?

A: Tire inflation pressure should be checked at least once a month when the tires are cold or have sat for at least three hours.

Q: Why should I pay extra to properly repair a flat tire when plugging is so much cheaper?

A: Unless you have x-ray vision, any damage on the inside of the tire cannot be detected when plugging the tire on the rim. By removing the tire from the rim, inspecting the interior, and repairing the damage with a plug/patch combination, the integrity of the tire can be restored.


Q: Why should I bring my car back to the tire dealer to check the lug nuts for proper torque?

A: Everyone knows the problems associated with loose lug nuts, but overtightening the lug nuts can be just as dangerous. A simple torque check shortly after a tire rotation or installation can identify a damaged stud or lug nut.

The Tire Contact Patch

How much rubber do you really think is in contact with the road?  On average it is only 4" x 4" square.  To just see how little, take a regular 8x11 sheet of paper and fold it into quarters.  Thats it.