Deciding that you need to buy tires is fairly simple. Making the correct decision on the right kind of tire for your vehicle, for your kind of driving, and for your pocketbook is not easy for many drivers. Make this simple test to see if your tire tread is too thin. Take a Lincoln-head penny and place the top of Lincoln’s head at the bottom of the shallowest tread groove. If you can see all of Lincoln’s head, the tread is too worn and it is time to buy a new tire. Some buyers make a blind selection because of a sale, or listen to a glib salesman who may or may not be giving unbiased information. The following information should help you select the tires that will be best for your car.
Remember that your safety depends on the selection, use, and care of your tires. Buy the tires that fit your car, the load to be carried by the car, your type of driving, your roads, and your pocketbook. Incidentally, American tire manufacturers have tires that will fit most foreign cars.
Automobile tires may be grouped as conventional (nonradial) tires and radial tires.
- CONVENTIONAL TIRES
The two kinds of conventional tires are the bias-ply tire (commonly called the bias tire) and the belted bias tire (commonly called the belted tire).
The bias tire has been on the market since about 1920. Cords are woven into layers, and each layer of cord is called a ply. The layers cross over one another at an angle to form the body of the tire. Plies
always come in even numbers-two-ply, four-ply, or six-ply-and are usually made of polyester. The more plies, the stronger the tire.
Bias tires are rigid in tread and sidewall, and “squirm” more than other types. Squirming is the tire experts’ term for the tread distortion I hat decreases traction and increases wear as the tire makes contact with the road. Bias tires tend to run hotter than other tires; and heat will shorten tire life. These tires usually are less expensive than belted or radial tires, and sales that advertise new tires at a surprisingly low price are probably for bias tires. The bias tire probably will be satisfactory if a car is driven at slow speeds around town, with little or no highway driving, but I do not recommend them for constant highway driving. Your neck and the lives of your passengers deserve a better, safer tire.
The belted tire has been available for about forty years. The body of a belted tire is constructed much like the bias tire, with crisscrossed layers or plies of overlapping polyester cord. The big difference in this tire is the two or more additional belts, bands, or layers of material that go around the tire under the tread. These belts are made of fiberglass, rayon, or nylon.
The belted tire squirms less than the bias tire, runs cooler, and gives more mileage, so that its cost ultimately may be less per mile than that of a bias tire, even though a belted tire costs more initially. This is a much safer tire, and I recommend it over a bias tire.
- RADIAL TIRES
Radial tires are the newest kind available. They were first manufac-tured and used successfully in other countries before appearing in the U.S., and have been available here for about twenty years.
The radial tire has one, two, or three plies, with the body cords run-ning at right angles to the center line of the tire tread. All radial tires are belted with up to four plies underneath the tread. Radial body cords offer a choice of materials: polyester, rayon, and nylon. Belts may be made of steel or fiberglass.
Radial construction creates a flexible sidewall, and the tires appear to be in need of air even when properly inflated. This characteristic makes it even more important to have your own tire gauge and to check the tire pressure at regular intervals. Ask the tire dealer for the proper inflation pressures.
The belted tire has been available for about forty years. The body of a belted tire is constructed much like the bias tire, with crisscrossed layers or plies of overlapping polyester cord. The big difference in this tire is the two or more additional belts, bands, or layers of material that go around the tire under the tread. These belts are made of fiberglass, rayon, or nylon.
The belted tire squirms less than the bias tire, runs cooler, and gives more mileage, so that its cost ultimately may be less per mile than that of a bias tire, even though a belted tire costs more initially. This is a much safer tire, and I recommend it over a bias tire.
- RADIAL TIRES
Radial tires are the newest kind available. They were first manufactured and used successfully in other countries before appearing in the U.S., and have been available here for about twenty years.
The radial tire has one, two, or three plies, with the body cords run-ning at right angles to the center line of the tire tread. All radial tires are belted with up to four plies underneath the tread. Radial body cords offer a choice of materials: polyester, rayon, and nylon. Belts may be made of steel or fiberglass.
Radial construction creates a flexible sidewall, and the tires appear to be in need of air even when properly inflated. This characteristic makes it even more important to have your own tire gauge and to check the tire pressure at regular intervals. Ask the tire dealer for the proper inflation pressures.
Radials run cooler, give the longest mileage (some radial tires are guaranteed by the manufacturer for 40,000 miles), are the safest, and cost the most of any tire available. Radial tires squirm less, and keep more tread on the road because of their belts and because they flex without heat build-up.This provides better traction, superior handling, mid stability in turns. Most reports state that radials also give better gas mileage; about 7 percent better mileage is the national average for cars.
If you prefer radials on a new car that does not have them, consult with the dealer about swapping the tires before you drive the car. If you are now using bias or belted tires and would like to change to radials as your tires wear out-which I recommend for sustained highway driving and greatest tire dependability-there is one serious problem: you will have to buy five radial tires and have them installed all at once (your spare has to be a radial, too).
Do not mix radial tires and conventional tires on your car! To do so is courting disaster as the car will sway easily, and steering can be difficult and dangerous. Be-fore installing radials, check with the tire dealer to learn whether a special front-end alignment is required. All newly installed tires must be balanced. A dealer normally charges separately for balancing and does not include this in the price of the tire. Radials usually make a lillle more noise than conventional tires-another factor to consider before switching to radials.
- ROTATION OF TIRES
All tires on a car do not wear at the same rate, and rotation usually helps to get maximum tire mileage. Bias and belted tires should be iolalcd about every 5,000 to 8,000 miles if you do the rotation yourself. One rotation plan is: spare to left front, left front to right rear, right icm lo right front, right front to left rear, and left rear to spare. This is “crisscross” rotation. Some tire authorities now suggest that if you luivt- lo pay for having your tires rotated you should leave them in the mime location up to 20,000 miles, unless one or more tires show unusual wear. Otherwise, the cost of rotation negates anything you have Kiivcil by having your tires rotated.
Do not crisscross radial tires. Always keep them on the same side nl the car to avoid unnecessary stress on the tire. Some owners rotate imli.il I ires to get more mileage. This is a good thing to do about every 5000 to 8,000 miles if you rotate the tires yourself. Otherwise leave the tires in their present positions up to 20,000 miles unless unusual wear develops. Here is a tire rotation plan for radials: right front to right rear, right rear to right front, left front to left rear, and left rear to left front. Note that the spare does not enter into this switch. Sooner or later one of the four tires will wear and need replacing, and you can install your spare and keep the worn tire as a spare for emergency purposes.
- SPECIAL TIRES
Various types of blowout- and puncture-resistant tires are on the market. Some have a steel safety belt under the tread; others have an inner tire separated from the main body by an air space; in some a sealant is used to prevent air from escaping if a puncture should occur. Some of these tires have excessive heat build-up, and others are difficult to balance. Snow tires are available for drivers who live in colder climates.
A new radial tire manufactured in the U.S. has recently appeared on the market. It is steel-belted like many other radials, but in addi¬tion has steel in the sidewalls. This tire is guaranteed for 50,000 miles. The manufacturer approves crisscross rotating this tire at intervals, as is done to a bias or belted tire.
Today’s trend is toward low, wide-profile tires. Wide tires provide better road contact and better cornering, but drivers of some cars without power steering report that turning is harder with wide tires. On older cars wide-profile tires may not fit the rims and may rub the fender wells during turns. Be sure to check these points before changing the type of tire on your car. Consult your Owner’s Manual and follow the manufacturer’s recommendations.
- TIRE QUALITY
At present no reliable rating system indicates the comparative quality of tires. There are no industry-wide, government, or other uni-form systems of quality grades or standards. For example, “premium,” “super,” “first line,” and “100 level” are brand grades or advertising terms and are not consistent from one brand to the next. Reports from unbiased tests, such as are found in Consumer Reports, are probably your best guides in selecting a quality tire.
All tires display certain kinds of information molded into the side-walls: size and load capacity, maximum pressure in pounds per square inch (psi), brand name, cord composition, and the number of plies for both sidewall and tread. The Department of Transportation (DOT) label indicates the tire meets federal motor vehicle safety standards
Size and load labeling of tires changed to a letter and numbering system several years ago. Charts are available at the tire dealer’s store to show you what the other letters and numerals on your tire mean. An example is F78-14. The first letter gives the tire load capability. The F designation means the tire will support 1,280 pounds of weight when inflated to 24 psi. A tire labeled N would support 1,880 pounds of weight. The 78 means the tire profile height is 78 percent of the tire width. The 14 indicates a 14-inch rim. If R follows the first letter, for example ER78-14, the R says it is a radial tire.
Do not be too concerned about all the letters and numbers on your tire, as your dealer will help you select the right size and load limit. Two important things to remember are: do not buy tires smaller than your cars original equipment, and do not overinflate your tires. The maximum pressure is shown on the tire, for example, “max inflation 32 psi.”
- TIRE PRESSURE
If the maximum pressure indicated on the side of the tire is 32 psi, put slightly less than the maximum-say 28 to 30 psi-in your tires. Owner’s Manuals usually recommend a tire pressure that is too low, sometimes as low as 24 psi. Remember the manufacturer of your car wants you to have a soft, easy, enjoyable ride, and he is not too con-cerned with the life of your tires. Reputable tire dealers will confirm these facts.
You should have your own tire gauge. To get an accurate reading, take the tire pressure when the tire is cold or has not been driven over one mile-the pressure inflates when the car is being driven (see Chapter 12, Four Regular Checks).
- TIRE CARE
If tires wear equally on both edges but not in the center, they need additional air pressure. On the other hand, the air pressure is too high if tires show wear in the center. If the front tires wear on one edge more than on the other, a problem of alignment or worn front-end parts exists. Have the alignment checked by a shop that specializes in this job.
Most drivers know that a new tire should be balanced in order to give a smooth ride and longer tire wear. What some drivers do not realize is that a new tire must be round within allowable limits, or else the tire will cause excessive vibration, and no amount of balancing is going to cure the vibration. Practically all tire manufacturers today produce some tires that are not perfectly round. Do not condemn all tires of a particular brand because you get one tire that is out of round. If your new tire still has excessive vibration even though bal¬anced, go back to your tire dealer and discuss the problem. A reputable dealer will usually have equipment to check the tire and the wheel and see if they are as round as they should be. If the tire is not round, he should “true” the tire or give you a financial adjustment on a new tire. Let me stress again the importance of buying a well-known brand of tire from a reputable dealer.
Trueing a tire consists of mounting the tire on a special machine that rotates the tire slowly while a sharp edge removes excess rubber until the tire is round within allowable tolerances. A small town may not have a shop that trues tires, but most cities have shops that offer this service.
Always keep a valve cap on the threaded valve stem of each tire to keep out sand, dust, and other foreign matter. A valve stem exten¬sion may be needed if the rims are fitted with covers. The extension seals the end of the valve stem and takes the place of a valve cap.
To get the longest wear from your tires, keep them inflated to the pressure I have recommended, have the tires balanced and trued if necessary, keep your front end aligned, and drive responsibly with no “burning rubber” when you start and no sliding when you stop. And never drive on a flat tire.
- FRONT-END ALIGNMENT
For long tire life the front end of your car should be properly aligned. Rear wheels do not need aligning on American cars; they will be aligned correctly unless a mechanical defect exists, such as a bent rear axle. (Some foreign cars should have the rear wheel alignment checked and corrected as well as the front wheel alignment.) When you put new tires on the front wheels, take the car to a reputable shop that aligns front ends and have the alignment checked. Usually the shop will not charge for this service, provided you agree to have any needed alignment work done at that shop. A reputable shop that aligns your front end cannot guarantee the alignment to last for a cer-tain period of time or a certain number of miles driven. You might leave the shop and immediately strike a pothole or boulder in the road, or bump into a curb too hard and throw the front end out of alignment
- GUARANTEES
Most new tires carry some type of guarantee, either on time or mileage. Adjustments are made on a pro-rata share of the number of miles or months the tire has been driven. Guarantees differ, so it is important to understand clearly all conditions and terms. Most tires are guaranteed for the life of the original tread and against tire failures resulting from ordinary road hazards and defects in materials and workmanship. When you return a defective tire to a dealer for a finan-cial adjustment, he measures the tread and determines the percentage of wear left in the tire. This percentage determines the amount of dis-count you receive on the cost of a new replacement tire. When tires have worn unevenly, the dealer makes the tread depth measurement where the greatest wear occurred.
You may void the guarantee by abusing the tire, such as driving on a flat. Proper tire pressure, proper balancing, and proper front-end alignment are also your responsibilities.
- CHECKING THE TIRES
When you are making the four regular checks every two weeks or every 500 miles, examine the tires to see whether any unusual wear is occurring. Uneven tread wear may indicate the alignment should be checked. Indentions or pits around the tire may indicate worn shocks that need replacing. A shimmy at highway speeds usually indicates that the tires need balancing; if the car pulls to one side when you lift your hands off the wheel, alignment may be the problem. Try¬ing to squeeze extra miles out of a badly worn tire can be dangerous and is false economy. Some states have periodic car inspections, and the tires are one of the things that are checked. About 90 percent of all flat tires occur after some part of the tire tread has worn to %6-inch or less.
Shop around when your tires begin to show signs of wear and need replacing. Prices for a particular tire often vary from one dealer to another. Watch the advertisements for tire sales that may save addi-tional money. Remember that the tire that costs the least is not neces-sarily the best bargain. Quality and tread life vary as do guarantees. Choose a dealer with a quality line of tires and a good reputation for service.
RECAPS AND RETREADS
Drivers who buy recaps and retreads are usually those who cannot afford new tires and who are willing to take the extra risk of tire fail¬ure. Some drivers use recaps and retreads successfully for slow, around-town driving. They are too dangerous for highway driving and carry¬ing heavy loads. Your safest, most dependable choice is to buy new tires.
PUNCTURES
Tire punctures happen to practically all motorists at some time. I suggest that you take the flat tire to a service station or tire dealer to have it repaired.
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