Today, nearly all tires have belts made from steel. Radial tires also last much longer than any previous tire design. Although driving habits and tire care play a key role in tire life, radial tires may last as long as 160,000 kilometres. Virtually all of today's tires used on automobiles, and many used on light trucks, have a tubeless design. This means there is not a separate balloon-like tube inside the tire, as was the case with older tire designs.

Tires serve as the wearable part of the overall tire/wheel assembly, but they also play a large role in vehicle safety. Today's tires must provide good traction under a wide range of driving and road conditions while providing long tread wear.

Check tire pressure frequently and also inspect the tires for abnormal tread wear and cuts and bruises along the sidewall. Rotate and balance the tires on a regular basis. If your car has a flat, have the tire professionally repaired. Since most flats are caused by damage to the tire, such as a puncture, anything less than quality repairs can affect the integrity of the tire. The best way to repair a tire is to have it removed from the rim, the inside inspected and corrective measures taken. The quick plug, done from the outside, is no longer recommended by the tire industry. According to experts, the repair could fail, inviting a blowout. When replacing tires, install only tires of the size recommended for your vehicle. Installing the wrong tires can result in contact with body panels or steering and suspension parts. The wrong tires can also affect speedometer readings and engine/transmission control.

Tires are a normal wear item and eventually you'll be faced with replacing them. When you do, making the right choices can make a big difference in your satisfaction once your new tires are installed.

With a P225/75R15 tire as an example, "P" represents passenger car applications (LT=Light Truck), 225 indicates the width of the tread in millimetres, 75 represents the aspect ratio (width of the tread, divided by sidewall height), "R" means radial construction (most tires nowadays) and the 15 means the diameter of the wheel in inches.

A tire may also carry a speed rating, which represents the maximum safe driving speed for a given tire. If this is the case, the rating will precede the "R". Speed ratings range from "S" to "Y", which represent 112 and 186 miles per hour respectively. (Speed-rated tires are usually used in high-performance applications.)

In most cases, cars and minivans are originally equipped with passenger car tires, whereas larger vehicles like pickups, SUVs and the like come equipped with light-truck tires. It's important to stick with the size tires and types as recommended by your car's manufacturer or in a tire application guide from a tire maker. Using tires of the wrong size can interfere with steering and suspension parts and it can affect the accuracy of your car's speedometer along with onboard control technology such as the transmission and anti-lock brakes.

There are three other factors that may be helpful in your tire selection process. These three "T's" are treadwear, traction and temperature. As with tire sizes, the codes for these are marked on the sidewall of the tire, too. The treadwear number is a relative indicator of just that -- the higher the number, the better. In theory, a treadwear index of 200 means that the tire will last twice as long as a tire with a 100 index.

Next, comes the traction index, which is expressed as a letter. A tire that performs well during braking on both wet concrete and asphalt gets an "A" index; a tire that performs well on only one of the surfaces gets a "B" index; and a tire that performs poorly on both surfaces gets a "C" index.

The last of the "T's" is temperature resistance. An "A" index means the tire has a high resistance to temperature; "B" means a medium temperature-resistance and a "C" index indicates that the tire meets basic safety standards.

There are still other considerations that go into formulating a tire choice that's just right for your car, based on personal preferences. This may include the type of tread for on- or off-road use, the amount of noise the tires produce when driving on paved surfaces and other appearance-related options like raised white letters or black sidewalls.

Tire rotation helps to equalize tread wear and is critical to gain the maximum life from your tire investment.

Refer to your owner's manual for the recommended rotation interval and pattern; generally a rotation interval of 10,000 kilometres is recommended. The rotation pattern varies with different makes and models, which shows the tire locations during rotation.

Some vehicles have different size tires on the front and back or directional tires. This limits the locations that a tire may take on the vehicle. When in doubt, check the owner's manual or consult a professional technician for guidance. Tire rotation time also offers a good opportunity to have the tires and wheels balanced. It is another step you can take to maximize your tire investment.

Are your tires set at the optimum inflation? Chances are they are anywhere from 8psi to 18psi less than recommended. The most common way of damaging tires is improper inflation. Correct inflation pressure is critical for good fuel economy, safety, maximum tire life, and proper vehicle handling performance. Under inflated tires can build up excessive heat and blow out without warning.

For the small amount of time it takes, checking tire inflation at least once a month is one of the best investments you can make to get the maximum life out of your tires. Always check your air pressure and make adjustments when the tires are cold. Proper inflation can also improve gas mileage by more than 3%, when maintained regularly.

Keep this in mind: Under-inflated tires can lower gas mileage by 0.4 percent for every 1 psi (pounds per square inch) drop in pressure of all four tires. You may want to check your tires more often during the winter months. Tires will lose about 1 psi of pressure for every 10 degrees Fahrenheit of temperature drop.

Keep an accurate tire pressure gauge in your car's glove box (many gauges at "air stations" give false pressure readings) and check the tire pressure when the tires are cold (tires have not been driven for 2 hours).