These buyer tips are provided by The Newsome Law Firm as a service to our readers and clients. If you have a question or concern regarding the purchase of tires for your vehicle that is not addressed here, please feel free to contact our office.

Determine the Age of the Tires by Decoding the DOT Number

When you're about to buy tires, check their age. Tires that are more than six years old are at greater risk of failing. A tire dealer may have tires on display or in the warehouse that look new but are actually too old to use safely.

• To determine the age of a tire for a passenger vehicle, see the inner circle of numbers and letters on the tire's sidewall. There is a series of numbers that starts with the letters "DOT" (Department of Transportation). This is the “DOT number.” The next two letters or numbers are a code for the factory where the tire was made, and the last numbers represent the week and year the tire was built .

• If the tire was made before 2000, the last single digit represents the year, and the numbers before that are the week: for example, 425 means the tire was made in the 42nd week of the year 1995.

• If the tire was manufactured in the year 2000 or after, the last two digits are the year it was made, and the number before that is the week. Thus, 1604 means the tire was made in the 16th week of 2004.

Know Your Tires' Speed Rating

A tire's speed rating symbol is on the outer circle of most passenger vehicles' tire sidewall markings. However, speed ratings aren't required by law, so they're not present on all tires. The speed rating tells you the maximum speed at which the tire was designed to be driven for long periods of time — anywhere from 99 to 186 miles per hour (mph). The speed ratings are coded by letter: Q=99 mph, R=106, S=112, T=118, and so on, through Y and Z for very high-speed tires. Don't buy tires that aren't safe for the speed you'll be driving.

Run-Flat Tires

Run-flat tires are designed to “run flat” — that is, even if a run-flat tire is punctured, it is designed to enable the vehicle on which it is mounted to continue to be driven (at reduced speed and for a limited distance). Run-flat tires used to be available mostly for little two-seater sports cars, but now they're also available for other vehicles, e.g., some luxury cars.

Buyer beware: run-flat tire makers (such as Michelin and Honda) have been accused of deception regarding:

• the possibility that their tires are vulnerable to premature wear and other issues
• the typically short life of a run-flat tire (sometimes one-fourth that of a regular tire)
• the cost of repairing or replacing the tires, which can be excessive
• the availability of repair/replacement facilities and the stocks of replacement tires

Run-flat tires aren't always a good option. Be careful to get all the relevant details if you're considering purchasing run-flat tires.

Low-Profile Tires

Low-profile tires have a short sidewall height — the amount of rubber between the road and the outside edge of the tire's rim or wheel. Low-profile tires thus have what could be thought of as having a “low profile,” a distinctive look, but with some disadvantages and advantages of which a tire buyer should be aware:

• Disadvantage: A rougher-feeling ride due to the decreased cushion between the tire's rim and the road surface. Every imperfection in the road (potholes, bumps) goes straight to the vehicle's suspension.

• Advantage: “Crisper” vehicle handling and greater positive feedback to the steering system.

Low-profile tires are more common on sports cars, but nowadays some vehicles with large-diameter wheels also have the option of using low-profile tires. A vehicle's owner's manual will state whether low-profile tires are an option.