Getting started

Despite advances in longer-lasting tires, actual tread life will vary by car type, tire type (such as all season or high performance), driving aggressiveness, and even road and weather conditions. Car owners still need to replace their tires a few times or more throughout the life of a typical vehicle. As the adage goes, nothing lasts forever.

Proper maintenance and responsible driving can maximize the mileage in a set of tires. Monthly tread inspections can inform when the tires warrant replacement, well in advance of the federally mandated tread-wear indicators. In most states, tires are legally worn out when their tread depth reaches 1/16 inch (or 2/32 inch as found on standardized tread-depth gauges). The easiest way to measure this, if you don't have a gauge, is to hold a penny upside down in the tread. If the top of Lincoln's head is visible, you need new tires. But using a penny standard doesn't work for all weather conditions. We have found in our tests that a tire with just 1/8-inch tread was notably worse in hydroplaning resistance and snow traction. By the time only 1/16 inch remains, wet-pavement cornering and braking drop off too. Based on our experience, when your tires have less than 1/8 inch of tread left, it's a good time to start shopping for replacement tires.

As a better indicator of tread wear, place a quarter upside down in a tire groove. The distance from the coin's rim to George Washington's hairline is about 1/8 inch. If you see more of his head, consider shopping for new tires.

Once a need for new tires is determined, it is necessary to identify the best tires for your vehicle and driving demands.

Put safety first

Look for tires that do well in our tests for braking, handling, and resistance to hydroplaning. Winter traction should also be considered, if applicable. Let tread wear, ride comfort, noise, and rolling resistance be tiebreakers. Our comparative tread-life tests demonstrate that a manufacturer's warranty doesn't always reflect how a tire will wear.

Look for tires that do well in our tests for braking, handling, and resistance to hydroplaning. Winter traction should also be considered, if applicable. Let tread wear, ride comfort, noise, and rolling resistance be tiebreakers. Our comparative tread-life tests demonstrate that a manufacturer's warranty doesn't always reflect how a tire will wear.

To find the size and type of tire recommended by the manufacturer of your vehicle, check the placard in the doorjamb or glove compartment, on the fuel-filler door, or in the owner's manual.

Using the

P205/55R16 94V tire as an example, the P prefix denotes a passenger-car tire, although many light-duty trucks use tires with this designation. LT is the designation for tires that are typically used on larger or heavy-duty light trucks. Some tires omit either prefix.

tire as an example, the P prefix denotes a passenger-car tire, although many light-duty trucks use tires with this designation. LT is the designation for tires that are typically used on larger or heavy-duty light trucks. Some tires omit either prefix.

The

205 is the tire cross-section width in millimeters, and

is the tire cross-section width in millimeters, and

55 is the ratio of sidewall height to cross-section width (55 percent).

is the ratio of sidewall height to cross-section width (55 percent).

R means radial-ply construction. And

means radial-ply construction. And

16 is the wheel diameter in inches. The number

is the wheel diameter in inches. The number

94 corresponds to the tire's maximum load capacity. The letter

corresponds to the tire's maximum load capacity. The letter

V is the speed rating indicating the maximum sustained speed, in this case up to 149 mph.

is the speed rating indicating the maximum sustained speed, in this case up to 149 mph.

Check out our report

how to read a tire for more details.

for more details.

Although we recommend buying tires with the same or greater speed rating as the original equipment tires, winter tires are the exception. When possible, look for winter tires with a speed rating that is close to or the same as the original tires they replace.

The tread-wear warranties manufacturers provide for their tires are pro-rated; the more miles on the tire, the less credit you get on a replacement. And most tire warranties only cover damage resulting from regular use and don't cover damage resulting from potholes or other road hazards.

Tire prices can vary widely by region, and retailer. Check independent tire dealers, online or mail-order stores, tire chains, car dealerships, department stores, and warehouse clubs. Be sure to ask whether the price includes mounting, balancing, and new valves, which can increase the total cost.

Look at the sidewall of a tire for a designation beginning with DOT (for Department of Transportation). The last four digits of the designation indicate the week and year of manufacture. For example, 3307 means the tire was made during the 33rd week of 2007. Don't purchase tires that are more than a few years old.

Types

There is a wide range of tires types and size available from popular brands such as Bridgestone, Dunlop, Goodyear, Michelin, and Pirelli. It pays to know what is currently on your vehicle and to learn about your options. There are three basic types of tires—car, truck, and winter—and each has a few choices in each category.

The choice of a car tire depends on how you drive, the type of tire included with your car, and the performance you want.

Because of their size, dynamics and how they are used, trucks and SUVs often require special tires. Some automakers advise sticking with the tire type that the vehicle originally came with. Consult the owner's manual to see if a specific type is recommended. You can often improve road handling by switching from an all-terrain tire to an all-season.

Winter tires If you drive often in wintry or icy conditions, then winter tires might make sense for you. Winter tires typically have faster tread wear than all-season tires because the tread is specifically designed to bite into snow and ice, and the rubber is formulated to stay pliable at freezing temperatures. Winter tires have a mountain/snowflake symbol on the sidewall. It indicates that they passed an industry test for severe snow use. All the winter tires we tested carry that symbol. Don't be misled by the M&S (mud and snow) designation found on the sidewalls of a tire. That doesn't mean it's a winter tire; it means only that the tire has a relatively open tread pattern.

Winter tires have treads with more biting edges for better grip on snow and ice, while their softer compound remains flexible even in extremely low temperatures. But on cleared roads, they might not grip as well as all-season tires and they often wear more quickly.

Features

The dimensions necessary to describe the tire fitment, found on the sidewall. In addition, you'll find the recommended tire size, as well as the speed and load ratings for your vehicle on a placard in the doorjamb, the glove compartment, or on the fuel-filler door. To understand how size, works, consider the common: P235/70R16. In this example, P denotes passenger-car tire, even though the tire may be designed for a light truck (an LT, or light truck, prefix is for heavy-duty light-truck tires). The number 235 is the cross-section width in millimeters, while 70 is the ratio of sidewall height to cross-section width (70 percent). R means radial-ply construction and 16 is the wheel diameter, in inches.

Found on the tire sidewall, this letter denotes the maximum sustainable speed and is found directly after the load index. For S-speed-rated tires, it's 112 mph; for T, 118 mph. Speed ratings for other tires include Q, 99 mph; H, 130 mph; V, 149 mph; and Z, 150 mph plus. While such speeds may seem wildly impractical, tires with higher speed ratings tend to provide better handling at legal speed limits. Choose tires that have a speed rating at least as high as the one specified on your vehicle's placard.

Found on the tire sidewall, this number is based on the weight the tire can safely carry. You'll find it after the tire size; the 94 load index for example correlates to 1477 pounds. Choose tires with a load index at least as high as the one that's listed on your vehicle's placard.

Every tire has a Department of Transportation (DOT) number following the letters on the sidewall. The last four digits determine the week and year the tire was made; for example, the digits 2204 would signify that the tire was made during the 22nd week of 2004. Don't buy tires more than a few years old.

This is a tire's maximum air pressure, given in pounds per square inch. But that doesn't mean you should inflate your tires to that pressure, since automakers typically recommend an inflation pressure well below the tire's maximum air pressure. Follow the advice on the vehicle's placard, often located in the driver's doorjamb, or owner's manual.

The vertical side of the tire, surrounding the wheel, is called the sidewall. Here you'll find important information, such as the tire size and load and speed rating, necessary to choosing a replacement.

These scores denote a tire's wet-stopping ability and temperature resistance. For traction, AA is best, C is worst. For temperature resistance, scores range from A (best) to C.

A comparative government required grade that indicates how well a tire will wear as compared to a standard reference tire graded 100. In theory, a tire graded 500 should last five times as long as one graded 100. But the tire makers assign these wear ratings.