Treadwear grades are an indication of a tire's relative wear rate. The higher the treadwear number is, the longer it should take for the tread to wear down.

A control tire is assigned a grade of 100. Other tires are compared to the control tire. For example, a tire grade of 200 should wear twice as long as the control tire.

Of current tires:

• 15% are rated below 200
• 25% are rated 201 - 300
• 32% are rated 301 - 400
• 20% are rated 401 - 500
• 6% are rated 501 - 600
• 2% are rated above 600

Traction grades are an indication of a tire's ability to stop on wet pavement. A higher graded tire should allow a car to stop on wet roads in a shorter distance than a tire with a lower grade. Traction is graded from highest to lowest as "AA", "A", "B", and "C".

Of current tires:

• 15% are rated "AA"    
• 77% are rated "A"
• 7% are rated "B"
• Only 4 lines of tires are rated "C"

Temperature grades are an indication of a tire's resistance to heat. Sustained high temperature (for example, driving long distances in hot weather), can cause a tire to deteriorate, leading to blowouts and tread separation. From highest to lowest, a tire's resistance to heat is graded as "A", "B", or "C".

Of current tires:

• 62% are rated "A"
• 34% are rated "B"
• 4% are rated "C"

Check your owner's manual or the Tire and Loading Information Label located on the driver's side door edge or post to find the correct size for your car or truck.

Proper tire pressure is the most important part of maintaining your tires. It affects safety, their durability, and your fuel consumption.

• Check the pressure of all tires, including your spare, at least once a month when the tires are "cold," meaning that the car hasn't been driven for at least three hours.
• Your tires' proper tire inflation pressure—measured in both kilopascals (kPA) and pounds per square inch (PSI or psi)—can be found on the Tire and Loading Information Label on the driver's side door edge or in your owner's manual. On new vehicles, the label will be located on the driver’s side doorjamb, called a “B-pillar.” If a vehicle does not have a B-pillar, then the label may be found on the rear-edge of the driver’s door. If the vehicle does not have a B-pillar, and if the driver’s door edge is too narrow, the label may be attached on an inward-facing surface next to the driver’s seating position.
  
  
• Keep a tire pressure gauge in your vehicle. A tire can suddenly lose pressure if you drive over a pothole or bump into a curb when you park.
• Newer vehicles have Tire Pressure Monitoring Systems, but these only activate a warning when a tire is significantly underinflated. You should still conduct a monthly tire pressure check to ensure your tires are always properly inflated.

Tire tread provides the gripping action and traction that prevents your car or truck from slipping and sliding, especially when the road is icy or wet. Tires are not safe and should be replaced when the tread is worn down to 2/32 of an inch.

• Check your tire's tread at least once a month when you're checking their pressure.
• Tires have built-in "treadwear indicators," which are raised sections that run in between the tire's tread. When the tread is worn down so that it's level with the tread indicator, it's time to replace your tires.
• You can also check your tread by placing a penny in the tread with Lincoln's head upside down and facing you. If you can see the top of Lincoln's head, replace your tires.

Having your tires balanced and a wheel alignment performed by a qualified technician is important for the safety of your vehicle and to maximize the life of your tires.

• Tire balancing ensures your wheels rotate properly and don't cause the vehicle to shake or vibrate. New tires should always be balanced when installed.
• A wheel alignment maximizes the life of your tires and prevents your car from veering to the right or left when driving on a straight, level road.

• Rotating your tires can help reduce irregular wear, which will help your tires last longer and maintain the fuel efficiency of your tires.
• Check your owner's manual for information on how frequently the tires on your vehicle should be rotated and the best pattern for rotation.
• If recommended by the vehicle manufacturer, rotate tires every 5,000 to 8,000 miles or sooner if uneven wear appears.
• For some vehicles, tire rotation is not recommended. If your front and rear tires are different sizes, you may not be able to rotate your tires. Check your owner's manual for guidance.

To maintain tire safety, purchase new tires that are the same size as the vehicle's original tires or another size recommended by the vehicle manufacturer. Check your owner's manual or the Tire and Loading Information Label located on the driver's side door edge or post to find the correct size for your car or truck. If you have any doubt about the correct size to choose, consult with the tire dealer. They can find the correct size tire for your vehicle.

All passenger cars, light trucks and vans that are model year 2008 or newer are required to come equipped with this feature. Some model year 2006 and 2007 vehicles are also equipped with TPMS. If you own a model year 2006 or 2007 vehicle, check with your dealer or your owner's manual to determine if it comes equipped with TPMS.

There are two different low tire pressure warning indicators allowed by the Federal standard. One icon is the cross-section of a tire with an exclamation mark inside. The other is a top view of a car with all four tires exposed. No matter which TPMS symbol your vehicle has, it will illuminate on the vehicle dashboard when your tire pressure is significantly under inflated.

When the TPMS symbol appears on your dashboard, it means at least one of your tires is significantly underinflated. You should inspect your tires and check the tire pressure as soon as possible. The symbol will extinguish after the tires are properly inflated.

On cold mornings, the TPMS symbol may illuminate for a short period of time and then turn off. This is likely caused by marginally low tire pressure that dips below the warning threshold overnight but rises to an acceptable level as the tires heat up through vehicle operation or an increase in external temperatures. If the TPMS symbol goes on and off, you should inspect your tires and check your tire pressure. The lamp should not illuminate when the tires are properly inflated.

All TPMS installed on 2008 model year vehicles and beyond are required to detect and warn the driver when the system is not functioning properly. A system malfunction may be indicated by a flashing of the TPMS symbol for 60 to 90 seconds with the warning lamp remaining illuminated after the flashing sequence. The flashing sequence followed by continuous illumination of the warning lamp will repeat at each subsequent vehicle start-up until the malfunction is corrected. You should contact your vehicle dealer for a system inspection.

Underinflated tires are visually difficult to detect. It is recommended that you inspect tires monthly with an accurate gauge. The TPMS is not intended to be a substitute for regular tire maintenance.

Tire aging occurs when the rubber and other components in a tire change over time due to service, storage, and environmental conditions.

Most of us drive our vehicles enough that the tires’ treads wear out, and we replace our tires before aging becomes an issue. However, if you own or use recreational vehicles, 15-passenger vans, collector cars, any other vehicles you don’t drive regularly, or if your annual mileage is low, you could be at risk.

In addition to infrequent use, exposure to sunlight and warmer climate, poor storage and poor maintenance also contribute to tire aging. Tire aging is a greater concern in the more southern parts of the Sun Belt states.

You cannot detect tire aging simply by looking at your tires. However, there are steps you can take to extend the service life of your tires.

• Conduct monthly maintenance inspections, focusing on proper tire inflation pressure, treadwear and tire damage, along with recurring tire rotation, and balancing and alignment services.
• If your car has a Tire Pressure Monitoring System (TPMS), pay attention to it! All passenger cars, light trucks, and vans that are model year 2008 or newer come equipped with this feature. If the TPMS symbol lights up on your dashboard, it means at least one tire is already significantly underinflated—you should take immediate action.

• You should stop using tires for several reasons, including if a tire’s tread is worn down to a minimum depth using the penny test, signs of physical damage (cuts, cracks, bulges, etc.), or signs of irregular wear or other damage due to underinflation or overloading. Don’t use your spare as a replacement for worn tires. 
• Consumers are strongly encouraged to be aware of not only their tires’ visual condition but also any change in how they perform. If you notice any tire performance issues, such as failing to maintain proper tire inflation pressure, noise, or vibration, consult a tire service professional.
• As tires age, they are more prone to failure. Some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear. You can determine how old your tire is by looking on the sidewall for your DOT Tire Identification Number (TIN) . The last four digits of the TIN indicate the week and year the tire was made. If the TIN reads 0308 it was made in the third week of 2008. Look on both sides of the tire. The TIN may not be on both sides.