Understand Tire Basics
Simply put, a tire is a flexible container of compressed air. This air container support the vehicle's load; propels a vehicle forward, backward and side-to-side; stops the vehicle; and cushions the load from road imperfections.
Today's tires have between 19 and 25 different components. 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 air. Fabric belts are wrapped around the inner liner. The bead is fastened to the bottom of the fabric belts and holds the tire to the wheel.
On top of the fabric belts are steel belts. These belts have two jobs: They give the tire stability and make the tread pattern as flat as possible. (A flatter tread means more contact with the road.) The tire tread is on top of the belts. There are different tread patterns for different types of tires. The sidewall on the side of the tire gives it stiffness and ride characteristics. A taller, softer sidewall will absorb more bumps, while a shorter, stiffer sidewall will provide better cornering ability and sharper steering response.
On the sidewall of every passenger-car and light-truck tire is an alphanumeric code that describes the dimensions of the tire. For most tires, this code will start with a "P." Some may start with an "LT" to signify light truck. Some tires may have a "Max. Load" indication. When selecting new tires, it is important to make sure a tire's load rating is at least a high as the tire you are replacing.
Choose the Right Tire
Perhaps the biggest mistake a consumer can make whenreplacing tires is not using the correct size. On the sidewall of your tire, you'll find a code that tells the tire's size and capabilities. Here's a sample code:
P195/60R16 63H M+S
- P - Type of tire
- 195 - Width of the tire across the tread in millimeters
- 60 - Aspect ratio of the sidewall compared to the width
- R - Radial construction
- 16 - Diameter of the rim in inches
- 63 - Tire's load rating
- H - Tire's speed rating
- M+S - Tire is suitable for all-season driving
If the tire-size code starts with LT instead of P, it means the tire is a light-truck tire. Light-truck tires are designed to have higher-load carrying capacities and are usually found on pickups and SUVs. These vehicles are not required to have LT tires, and in many cases, the original-equipment specification calls for passenger-car tires.
The speed rating translates into the tire's ability to dissipate heat, or prevent heat build-up. Heat is a tire's enemy. The more heat, the faster the tire wears, and the faster a tire might break down. A tire with a higher speed rating can dissipate more heat on long highway trips. If a consumer were to spend little time on the highway, the speed rating might not be an important factor in choosing a replacement tire.
Tires are speed rated from 99 to 186 miles per hour (159.3 to 299.3 kilometers per hour). The most common speed ratings are T (118 miles per hour or 189.9 kilometers per hour) and H (130 miles per hour or 209.2 kilometers per hour). Both of those ratings clearly exceed the nationally posted speed limits and would make excellent long-distance highway tires. If a consumer were to drive only in urban situations at low speeds, a tire with an S (112 miles per hour or 180.2 kilometers per hour) speed rating might be completely acceptable.
Another important factor in choosing a replacement tire is the load rating. The load capacity number on the tire-size code indicates the load-carrying capacity of that single tire. When selecting replacement tires, consumers have to be careful not to select a tire with a lower load-carrying capacity.
Regardless of a tire's speed rating, load-carrying ability, size and construction, traction are the keys to safety. A common mistake is to select a tire without considering its ability to hold the road. Savvy consumers will balance a tire's traction in dry conditions, in wet conditions and in the snow. If you desire a high-performance tire but live in northern climates, consider a "winter" tire for driving in the snowy season. If you live where the weather is warm all year, a touring tire may suit your needs just fine.
Most consumers will make the mistake of waiting until spring to get new tires. As a tire wears out, dry traction generally increases and wet and snow traction decrease. So the best time to buy new tires is not in the spring, but in the fall.
Passenger-car and light-truck tires are very different. Pickup and SUV owners will generally select passenger-car tires because they are less costly and offer a smoother ride. However, if a vehicle will consistently be loaded with cargo or will be asked to pull a heavy trailer, then perhaps the higher load-carrying capacity of a light-truck tire would be the better choice.
Consider How You Drive
Regardless of where you get new tires, there are a few things you should keep in mind:
- Know the size and type of tire recommended by your owner's manual.
- Determine your needs and priorities. What type of driving you will be doing? Do you prefer a soft ride, a firm ride, or a mix of the two?
- Make sure you purchase a tire that is capable of supporting the load your vehicle might demand. Don't buy a passenger-car tire if you need a light-truck tire.
- Don't buy more tire than you need. Consumers often overestimate their tire needs. In most cases, a quality all-season tire will suffice where a touring tire might be suggested.
- Keep in mind that any tire selection is a balance between ride quality, noise suppression, fuel economy, wear, load capability and cost. It's the job of the tire-store expert and the consumer to select a tire that is the right balance of each.
- An interesting trend in the automotive aftermarket industry is "plus sizing." It involves mounting bigger wheels and tires on a vehicle to enhance the look or improve handling.
Plus sizing usually increases cornering response and traction. Often these gains come at the expense of increased ride harshness. In addition, these larger wheels and tires are often not as durable as OEM wheels and tires.
A few items of note for consumers considering plus sizing:
- Make sure that the tire and wheel are approved for use on your vehicle.
- Make sure that the replacement tire has the same load-carrying capacity.
- The new wheel and tire combination should be within 3 percent +/- the original tire diameter.
- Make sure that a new tire placard is installed to inform future owners of the correct tire pressure.
New vs. Used Tires
You've probably seen used car tire piles along the side of the road at some point. But should you purchase a used tire to save money and will it hold up as long? Most people opt for new tires, but some look to used tires as a way to save money.
Consider the fact that some retailers have deals where you buy three tires and you get the fourth free. You may not necessarily need to replace that fourth tire, but you do because it's free. Used tires that are only slightly worn, like in this situation, may be a good option to save a little money.
The flip side is purchasing an old or worn out tire that isn't safe. Used tires may have defects, punctures or tread-wear you may or may not be able to see. When considering purchasing a used tire you can test the depth of the tread by using a penny. Simply flip the penny upside down and place it inside each of the tire's tread grooves. If the top of Lincoln's head can be seen from any of the grooves then the tread is too low [source: Consumer Reports].
If the tread is still good, you still need to inspect the tire for any defects. This may be difficult and some problems may not be noticeable until the tire is on the vehicle. Purchasing a used tire that has already been plugged or patched may save money, but is not a good idea. Worn tires will not stop as fast and will be more likely to skid on wet surfaces [source: Consumer Reports].
New tires will come with some type of guarantee or warranty that a used tire will not have. If you want a little piece of mind that your tires are in the best condition possible, buy new ones.
Read more tire buying tips: http://auto.howstuffworks.com/buying-selling/cg-tire-buying-tips.htm
