Tires should be inflated to the pressure recommended by the manufacturer of your car. The most important part of tire care is A I R -- and its free (almost).
- Check tire inflation regularly
- Check at least every two weeks and before any long trips.
Under inflation: The worst enemy a tire can have is too little inflation pressure. An under inflated tire generates excessive heat, which reduces fuel economy and increases tread wear in the shoulder area. Inflating your tires to, but not over, the maximum inflation pressure specified on the tire sidewall can improve your fuel economy and extend tire life. The maximum inflation pressure is 32 psi for load range B alphanumeric sizes and 35 psi for standard load P-metric sizes.
Always check tire pressure in the morning before you drive or after driving a mile or less. Beyond that, check the tire pressure only after the tires have cooled down for an hour or more.
Radial tires: Because their normal shape has a slight sidewall bulge, radial tires require even more careful inflation checks. To be sure your tires have the correct air pressure, always use a good air pressure gauge.
Vary inflation with load: When your car is carrying extra weight, such as on a vacation trip, a little additional air should be added to the tires. We recommend increasing the air pressure 4 pounds over the car manufacturer's recommended cold tire pressure -- but not over the maximum inflation limit shown on the tire's sidewall. Never "bleed" or reduce air pressure when tires are hot. A tire's air pressure will automatically increase as its internal temperature increases. This increase is normal and should not be adjusted. Check and adjust inflation only when tires are cool.
Check regularly to see that your tires have valve caps. Be sure they are screwed down finger-tight. Valve caps should have a rubber seal which provides a secondary air seal and keeps dirt and moisture out of the air valve.
Check out Over Inflationand Under Inflationfor illustrations of the consequences of too much or too little air.
Some people say out-of-balance wheels can rob my tires of thousands of miles. Is this true?
Definitely. In order for a tire to run true, weight of the tire and wheel assembly must be distributed uniformly. A heavy spot in the tire and wheel assembly must be counterbalanced by precision-made wheel weights. Improper balance could lead to "cupping" and excessive wear of the tread at the heavy spot. The tread will eventually cup out to the point where the tire will no longer be usable. In addition, the constant bouncing of the tire will lead to excessive tire wear.
Is there more than one type of wheel balancing?
Tire and wheel assemblies can be balanced in two ways -- statically and dynamically.
In static (up and down) balancing, the assembly is mounted on a freely moving spindle. If, after rotation, one point consistently pulls to the bottom, the assembly is showing a heavy spot; weights are placed diametrically opposite to counterbalance it. After the weights are added, the heavy spot is gone and the tire and wheel assembly will rotate on the spindle and stop in any position, without a heavy spot. On your car, a tire and wheel assembly that is out of balance will thump and cause tire flat spots where the heavy spots are.
Dynamic (two plane) balancing reveals whether a tire is unbalanced up and down and also whether one side of a tire and wheel assembly is heavier than the other. Dynamic unbalance is reflected in a noticeable vibration sometimes described as "shimmy." It is corrected by equalizing the weight on both sides of the tire and wheel assembly.
NOTE: Radial tires should always be dynamically balanced.
When should wheel balancing be done?
Tires and wheels should be balanced when new tires are mounted on wheels for the first time, when a tire and wheel are put in another position on the car, when used tires are installed on existing wheels after flat repair, or any time tire is dismounted. Balance should also be checked at the first sign of vibration, "shimmy," or unusual tread wear. Vibration or irregular tread wear may also be caused by misalignment or mechanical problems. A professional diagnosis will reveal the true cause.
How important is alignment for longer tire life?
Proper alignment is mandatory for even tread wear and for precise steering. Front and rear tires should be checked periodically for signs of uneven wear. Any changes in handling or steering response can also indicate misalignment. The moderate cost of having your car's alignment checked can more than pay for itself in tire mileage, performance, and comfort.
Thought you'd ask ... A vehicle is said to be properly aligned when all suspension and steering components are sound and when the tire and wheel assemblies are rolling straight and true.Because the system is flexible, involving moving parts, some wear of the steering and suspension components is normal and can be expected. As these parts wear, misalignment occurs. This increases the imposed loading and rate of wear. The result is that the tires may not roll as straight and free as they should, causing scuffing and uneven, sometimes rapid tread wear.
Why "vehicle alignment"? Is that the same as "front-end alignment"?
Many vehicles today are equipped with a rear suspension design that allows adjustments for rear wheel alignment or with a design that requires a rear wheel check. When a rear suspension is not in alignment, it may create problems for the front as well as the rear wheels -- problems like an apparent crooked steering wheel (center line steering), Camberor Toeinduced front tire wear, and directional pull or lead. Cars have changed. Suspension, steering, and drive train design all require a total-vehicle, four-wheel approach to alignment for proper performance of today's vehicles.
Any discussion of alignment usually involves three terms -- caster, camber, and toe. What is "toe"?
This describes the measured distance between the front of the two tires on the same axle as compared with the distance between the rear of the same two tires.
Proper Toemakes the tires roll essentially parallel to each other with the tread true and flat against the road, and compensates for steering linkage flex under torque.A small amount of toe-in is required for optimum vehicle handling and to prevent steering "wander". Excessive toe-in, however, causes a feather-edging type of wear on the outside edges of the tire tread. Too much toe-out causes the reverse -- feather-edging of the inside edges. Radial tires may show still other types of wear as a result of improper toe -- sometimes a diagonal, wiping type of wear across the tread.
Incorrect toe on rear wheels also causes irregular wear. In addition, incorrect rear wheel toe can cause the vehicle thrust line to vary from the centerline of the vehicle, causing tracking problems as well as problems with the front tires.
Camber is a measure of the tilt of the top of a wheel inward or toward the vehicle or outward and away. Negative camber is the tilt of the top of a wheel inward toward the vehicle. Too much negative camber causes accelerated wear on the inside edge of the tire. Positive camber is the reverse -- the tilt of the wheel outward or away from the vehicle. Too much positive camber causes accelerated wear on the outside edge of the tire.
Camber can be positive on one wheel and negative on the other wheel on the same axle. Or it can be negative (or positive) on both wheels on the same axle.
In some cases, unequal camber can cause a vehicle to lead or pull toward the side having more positive camber.
This is the forward (negative) or rearward (positive) tilt of the spindle steering axis on a car or the kingpin on a truck. Correct caster on a vehicle is never perfectly vertical but is always set on a slight angle. A bicycle provides a good example of caster. The front fork on which the front wheel is mounted is almost always tilted back, giving the front wheel positive caster.
The basic purpose of caster is to maintain directional control, give more on-center "feel" to steering, and return the vehicle to a straight ahead position when exiting a turn. Insufficient caster causes wander, road shock, and a light feeling in the steering. Excessive positive caster can cause hard steering, shimmy, and tire wear in extreme cases. Unequal caster causes the vehicle to pull or lead toward the side having the least positive caster.
When caster is out of manufacturer's specification range, tire wear may occur as a result of incorrect camber on turns. However, loose or worn steering or suspension parts that would produce an incorrect caster angle would also affect camber and toe, which would also cause tire wear.
What type of car maintenance helps increase tire life?
Correct vehicle alignment is a must and should be checked periodically. Improper alignment not only can cause excessive tire wear, it also can increase fuel consumption. Tires and wheels should be balanced dynamically -- rear wheels as well as fronts. We recommend "off the car" computer balancing. (See Types of Tire Balancing.)
What should I do if I notice a vibration?
Vibration is an indication that your car has something that needs attention. The tires should be checked for irregular wear to help determine the possible cause and correction of the vibration. If left unattended, the vibration, if caused by tires, could cause excessive tire and suspension wear. It could even be dangerous.
Can my driving habits affect the life of my tires?
They certainly can. Here are some tips to increase the life of your tires:
- Don't speed: excessive heat is generated from the flexing of the tire's carcass when driven at high speeds. This heat increases the rate of tire wear and reduces the tire's durability.
- Avoid fast turns on curves and around corners; fast starts and panic stops; riding on the edge of the pavement; and driving over curbs, chuck-holes, or other obstructions.
Is it safe to repair a flat tire?
If a tire loses all or most of its air pressure, particularly at high speeds, it must be removed from the wheel for complete internal inspection to be sure it's not damaged. Tires that are run even short distances while flat are often damaged beyond repair.
Most punctures, nail holes, or cuts up to 1/4 inch -- confined to the tread -- may be satisfactorily repaired by trained personnel using industry approved methods, applied from inside the tire to seal the innerliner and fill the injury.
DON'T REPAIR TIRES WITH TREAD PUNCTURES LARGER THAN 1/4 INCH, OR ANY SIDEWALL PUNCTURE.
Your best bet is to make sure your spare tire is always ready to do the job. Check it regularly for proper air pressure and be sure that it is in good shape. If your car is equipped with one of the several types of temporary spares, be sure to check the spare tire's sidewall for the correct inflation pressure, speed, and mileage limitations.
Where should I store my extra tires?
Stack the tires on a smooth, oil-free floor. Plastic tire storage bags, usually available where you buy Goodyear tires, are practical and convenient. Pick a spot in your garage or basement that is cool, clean, dry, sunless, and away from strong air currents.
Motors generate rubber-damaging ozone gas that could affect your tires.
YES! Regular tire rotation promotes more uniform wear for all of the tires on a vehicle. Check your car owner's manual for the manufacturer's rotation recommendations. If no rotation period is specified, tires should be rotated every 6,000 to 8,000 miles. The first rotation is the most important.
If the tires show uneven wear, ask the serviceman to check and correct any misalignment, imbalance, or other mechanical problem before rotation.
When tires are rotated, inflation pressures must be adjusted according to the vehicle manufacturer's recommendations.
How can I check my tires for wear problems?
Tires often give their owners signs of problems in plenty of time to have them corrected. By learning to "read" these early warning signs, you can prevent many wear problems that shorten tire life by thousands of miles. Look for problems like these --
- Do the edges of the tread take on a saw tooth appearance?
This is caused by erratic scrubbing against the road. The solution is toe-in or toe-out alignment correction. For further details, you should see the section that illustrates Toe.
- What is a simple test for tread wear?
In addition to testing your tires visually for wear, there's a simple test you can perform to measure tread depth on your tires. Place a penny into a tread groove with Lincoln's head upside down and facing you. If you can see the top of Lincoln's head, you need a new tire.
- Is the tire wearing faster on the outer edges than in the middle of the tire?
When a tire is under inflated, most of its contact with the road is on the outer tread edges or the shoulder area, causing faster wear here than in he middle. Be sure to check the tire's air pressure. For further details, you should see the section on Under Inflation and Over Inflation as well.
- Is the tire wearing excessively on one side?
This is most likely another type of alignment problem -- excessive camber, which means the tire is tilted too much to the inside or outside, placing too much of the work on one side of the tire tread. For further details, you should see the section about Camber
- Do "dips" or "cups" appear in the tread?
This may mean you need your wheels balanced, or possibly new shock absorbers or suspension parts. For further details, you should see the section on Worn EquipmentThe rear tires on front wheel drive vehicles may show irregular wear due to the light loads on the rear axle. The solution is to rotate the rear tires to the front to even out the wear.
The front tires on front wheel drive vehicles may show faster wear than the rear tires because they do most of the work. To obtain more even wear, the tires may be rotated so all four tires wear out at approximately the same mileage. Check your vehicle owner's manual for the recommended rotation.
Must I replace my present tires with the same size tires?
Never choose a smaller size than those that came with the car. Tires should always be replaced with the same size designation -- or approved options -- as recommended by the auto or tire manufacturer.
Should I "mix" tire types on my car?
Tires of different size designations, constructions, and stages of wear may affect vehicle handling and stability. For best all-around performance, the same type tire should be used on all four wheel positions -- unless special purpose tires (snow tires, for example) are used to improve performance. You can mix your present tires with other size designations or constructions -- provided similar tires are used in pairs on the same axle. Get specific information from your tire retailer.
When buying just two new tires, should they be put on the front or rear?
When radial tires are used with bias or bias belted tires on the same car, the radials must always be placed on the rear axle. When you select a pair of replacement tires in the same size and construction as those on the car, We recommend you put them on the rear axle. A single new tire should be paired on the rear axle with the tire having the most tread depth of the other three.
Isn't it easy to mount a tire on a wheel? Can't I do it myself?
Tire mounting is a job for the people who have the proper equipment and experience. Most tire retailers offer free mounting service when you purchase new tires. If you try to do the mounting yourself, you run the risk of serious injury to yourself as well as possible damage to tire beads and rim.
So -- never try to mount your own tires. Only specially trained persons should mount or demount tires. An explosion of a tire and wheel assembly can result from improper or careless mounting procedures.
If you do mount your own tires, make sure you have the right equipment, the right training and the right information before proceeding. Always use a restraining device when mounting a tire on a rim, and be sure to stay back from the tire when inflating it. Make sure to follow the inflation instructions. Contact the Tire Industry Safety Council at (202) 783-1022, the National Tire Dealers & Retreaders Association at (202) 789-2300 or the Rubber Manufacturers Association at (202) 682-4800 for proper mounting and demounting information. For information on federally mandated truck tire mounting procedures, contact the Occupational Safety and Health Administration at (202) 219-4667.
While it is possible to pass a 16" diameter tire over the lip or flanges of a 16.5" size diameter rim, it cannot be inflated enough to position itself against the rim flange. If an attempt is made to seat the tire bead by inflating, the tire bead will break with explosive force and could cause serious injury or death.
Remember, mounting and demounting tires and wheels should be left to skilled professionals who are aware of the safety hazards involved and who have the proper tools and equipment to do the job safely.
Do my new tires require any special treatment?
The new tires that you put on your car will probably feel different from the tires that were replaced. You should drive carefully until you are familiar with their performance and handling. Take special care when braking, accelerating, cornering, or when driving in the rain, because these are the times when the differences will be most noticeable.
