Tire Maintenance

Underinflation can lead to tire failure. It results in unnecessary tire stress, irregular wear, loss of control and accidents. A tire can lose up to half of its inflation pressure and not appear to be flat!
You can't tell if your tires have enough inflation pressure just by looking at them. Even though they may look fine, they may be underinflated by as much as 50%. According to a recent study, about 70% of the vehicles on the road have at least one tire that is either over or underinflated by more than 10%. In fact, 23% of all vehicles surveyed had at least one tire underinflated by 20% or more. This represents a real safety issue.
It’s important to have the proper inflation pressure in your tires, as underinflation can lead to tire failure. The “right amount” of inflation pressure for your tires is specified by the vehicle manufacturer and is shown on the vehicle door edge, door post, glove box door or fuel door. It is also listed in the owner’s manual.
1. When you check the inflation pressure, make sure the tires are cool — meaning they are not hot from driving even a mile. (NOTE: If you have to drive a distance to get inflation, check and record the tire pressure first and add the appropriate inflation pressure when you get to the pump. It is normal for tires to heat up and the inflation pressure inside to increase as you drive. Never “bleed” or reduce inflation pressure when tires are hot.)
2. Remove the cap from the valve on one tire.
3. Firmly press a tire gauge onto the valve.
4. Add inflation to achieve recommended inflation pressure.
5. If you overfill the tire, release inflation by pushing on the metal stem in the center of the valve with a fingernail or the tip of a pen. Then recheck the inflation pressure with your tire gauge.
6. Replace the valve cap.
7. Repeat with each tire, including the spare. (NOTE: Some spare tires require higher inflation pressure).
8. Visually inspect the tires to make sure there are no nails or other objects embedded that could poke a hole in the tire and cause an inflation pressure leak.
9. Check the sidewalls to make sure there are no gouges, cuts, bulges or other irregularities.
Rotation: Taking Turns
You can slow down uneven tread wear by rotating your tires-which simply means moving them around so that they "trade places" on your vehicle in a systematic way. Rotation is important because each tire on a car carries a different amount of weight, making them wear at different rates. By rotating them, you basically even out those differences. Your owner’s manual will tell you how often to rotate your tires, but as a rule of thumb, it should be done every 5,000 to 8,000 miles. You might want to rotate them sooner if you see signs of uneven wear. Misalignment and other mechanical problems can also cause such wear, so check with your mechanic to determine the cause.
There are various patterns for rotating tires (see below). A common one for front-wheel drive vehicles involves moving the tires in a criss-cross fashion, with the left front tire trading places with the right rear, and right front trading with the left rear. If you have a full-size spare, you can include it in your rotation pattern-but don’t do so with a small "temporary use" spare, because those are meant only for low-speed, short-distance emergency use.

NOTE: If your tires show uneven wear, ask your tire service professional to check for and correct any misalignment, imbalance or other mechanical problem involved before rotation. Before rotating your tires, always refer to your vehicle owner’s manual for rotation recommendations. If no rotation period is specified, tires should be rotated approximately every 5,000 to 8,000 miles.
Many vehicle manufacturers recommend replacing all tires on the vehicle at the same time. This makes rotation even more important for maintaining uniform tread depth and optimum tread wear of the entire set.
In the absence of vehicle manufacturer rotation recommendations, follow the rotation patterns in the diagram. Note that certain types of tires cannot be rotated in the manner shown. Such tires may include directional and asymmetrical tires. Also, some vehicles may have different sized tires mounted on the front and rear axles, and these different sized tires have rotation restrictions. For these special cases, check the recommendations in the vehicle owner's manual for proper rotation.
When tires are rotated, the inflation pressures must be adjusted for the tires' new positions in accordance with the vehicle manufacturer's recommendations; refer to the vehicle tire placard, certification label, or owner’s manual.
If the vehicle has a matching full-size spare tire, it is recommended that it be included in the tire rotation. Use one of the tire rotation patterns illustrated, inserting the full-size spare at the right rear position. Always check and adjust the inflation pressure of the full size spare when incorporating it into the rotation pattern. Do not include a "Temporary Use" or T-type spare tire in any of these rotation patterns.
A bad jolt from hitting a curb or pothole can throw your front end out of alignment and damage your tires. Have a tire service professional check the alignment periodically to ensure that your car is properly aligned.
Misalignment of wheels in the front or rear can cause uneven and rapid treadwear and should be corrected by a tire service professional. Front-wheel-drive vehicles, and those with independent rear suspension, require alignment of all four wheels. Have your alignment checked periodically as specified by the vehicle owner's manual or whenever you have an indication of trouble such as “pulling” or vibration.
Also have your tire balance checked periodically. An unbalanced tire and wheel assembly may result in irregular wear and vehicle vibration.
Another critical part of your tire is the tread, which gives you the traction to stop and hold the road on curves. Tire tread also funnels water out from under the tire, which helps to reduce "hydroplaning," where a car actually rides up on a layer of water and becomes dangerously difficult to steer or stop. Well worn or bald tires can result in hydroplaning, loss of traction and are more likely to be damaged by potholes and other road hazards.
Replace tires when worn to 2/32 inch (1.6 mm) tread depth anywhere on the tread face. To help you see when the tread is worn out, tires have a built in "tread wear indicators" at six locations around the tire.

These are narrow bars of smooth rubber that run across the tread. When the tread is even with the bars, a tire is worn down to 2/32 inch and the tire must be replaced immediately. You can also try the penny test: place a penny in the tire's most worn groove with the Lincoln's head facing down. If you can see the top of the Lincoln's head, the tire should be replaced.

According to the NHTSA, about one out of every 10 cars on the road has at least one worn out or bald tire. There are several things you can do to stay out of that group, and help the tread last longer on your tires. For starters, make sure that your tire service professional balances your tires when installing them. Balancing involves placing small weights on the rim to counteract heavy spots, or slight variations in weight, in the wheel. If a tire is not balanced, it will shimmy as you drive, and your tread will wear down quickly. You must also make sure that your car’s suspension is properly aligned.
Operating a vehicle with just one tire underinflated by 8 psi (56 kPa) can reduce the life of the tire by 9,000 miles and can increase the vehicle's fuel consumption by 4%.
In addition to wear out, if any of the following conditions below are found when inspecting a tire, rim/wheel or valve, the item should be removed from service. (Note: this list is not all-inclusive.)
- Localized spot wear
- Exposed cord or fabric material
- Unrepairable punctures
- Previous improper repairs
- Bulges, blisters
- Deep cuts/cracks
- Run flat damage
- Bent, cracked, corroded or damaged rim/wheel
- Damaged valve and/or valve core
Consult a tire service professional with any questions or concerns regarding tire, rim/wheel or valve conditions,