Tire talk: Tire Care and Replacement

There are some easy things you can do to prolong the life of your tires and improve your vehicle's safety.

Keep your tires properly inflated -- correct air pressure is required for good handling and traction, good fuel economy and even wear. The only way to determine proper tire pressure is to use an accurate gauge. Tire pressure should be checked and corrected only when the tires are cold; even a short drive can make your tires too hot for accurate pressure readings. Don?t inflate tires to the maximum pressure printed on the tire -- use the tire pressure recommended in your vehicle?s owners manual or tire information sticker (located in the glove box, on the door post, or inside the fuel door). Remember to check the pressure in your spare tire

Checking Your Tire Pressure
The main reason you should care about tire pressure is car performance. Cars are easier to handle when the tire pressure is correct. Properly maintained tires also last longer, and improve your gas mileage.

The best way to maintain your tires is to buy an inexpensive tire pressure gauge. The correct tire pressure is printed on the sidewalls -- or the outside, non-tread part -- of your tires. It's also listed in your manual, and is often listed on a sticker in the glove compartment or on the door jamb. The pressure is listed in pounds per square inch, or PSI.

Here is how to check your tire pressure:

1. Find an air pump at a gas station and park so that the air pump hose can reach your tire comfortably. It's best to check tires when they are cold -- that is, when you haven't been driving on them for very long.
   
2. Remove the tiny black valve cap on the valve that comes out of your tire, near the hubcap.
   
3. Press the round part of the tire gauge firmly onto the valve. Try to press it so that the hissing sound of air escaping from the tire stops while you're pressing. When it does, you'll get an accurate reading..
   
4. Read the gauge like a thermometer. The highest number you see closest to the stem of the gauge is the PSI. That number should match the recommended PSI for your tire
   
   
   
   • If the gauge reading is higher than it should be, use your finger, or the notch on the opposite side of most tire gauges, to release a bit of air by pressing it on the pin inside the tire valve.
     
   • If the gauge reading is lower than it should be, use the pump to add more air. On some pumps, you'll have to take the hose completely off the hose cradle to activate the pump. Press the head of the air hose firmly onto the tire just like you did with the tire gauge.
     
   • Check your tire pressure with the gauge again, repeating your steps until you get the PSI right.
     
   • Don't forget to replace the valve cap.
     
   
   

Changing a Flat Tire

Changing a flat can be a miserable experience for anyone. But if you have a jack, a lug wrench and a spare tire, you are half way there.

1) First Steps

• When you're driving and feel the rumble of a flat tire, slow down, turn on your hazard lights and try to park the car on level ground as quickly as possible.
  
• Put the automatic transmission into park and put the emergency brake on. If you have a manual transmission, leave it in first gear and pull the emergency brake.
  
• If you have to park on even a slight incline, try to find a heavy object to wedge up against the good tires. This will help to keep the car from rolling when you have it jacked up.
  Once you've parked, take out the lug wrench, jack and the spare tire from the trunk.
• Make sure the spare tire has enough air in it.
  

2) Remove the hubcap and loosen the lug nuts

• Pry off the hubcap with a screwdriver. Sometimes the lug wrench has a screw driver at the end of it. If it does, use that. Some cars don't have hubcaps at all.
  
• Now use the lug wrench to loosen the lug nuts, which are the hexagonal bolts under the hubcap. If the lug nut has an L on it, turn clockwise. If it has an R or doesn't have anything on it, turn counterclockwise. Try to loosen the nuts an equal amount.
  
• Very important: Don't remove the lug nuts yet. Just loosen them
  

3) Jack Up the Car

• Put the jack on the ground near the flat tire, under the car frame. Make sure it is under something structural that can support the weight of the car.
  
• Start pumping the jack, so that the top of it reaches the bottom of the car. When it does, keep going until the flat tire lifts off the ground. If the car seems unstable, lower the car, reposition the jack and try again.
  
• Very important: Never get under the car when it is jacked up.
  

4) Change the Tire

• Now that the flat tire is in the air, remove the lug nuts and place them in the upturned hub cap, or someplace easy to reach later.
  
• With all the lug nuts removed, pull the tire off by pulling it toward you. It will be heavy, so be careful it doesn't fall on you
  
• Put the spare tire on, positioning it so that the holes line up with the lug bolts.
  
• Replace the lug nets and tighten them, turning the opposite way you did when you removed them
  
• Put the spare tire on, positioning it so that the holes line up with the lug bolts.
  
• Replace the lug nets and tighten them, turning the opposite way you did when you removed them
  
• Then lower the jack even further and remove it.
  
• Put the flat tire, hubcap, jack and the lug wrench back in the trunk.
  
• Don't forget to remove the wheel blocks.
  
• Get your original tire fixed as soon as you can. Your spare may be only good for short distances at low speeds.
  

Car Tire Replacement Advice

When your tires wear out, you have to decide how you?re going to replace them. Often it's not just a simple matter of buying the exact tires that came with the car -- they may have been discontinued; may cost a lot more than a comparable brand; or may not fit your driving style. Don't skimp on your tire purchase if you care about your car's ride and handling. Conversely, if you only drive sedately and your car's expensive low-profile performance tires have worn out, don't break the bank to replace them if a lesser tire will fit. Determine if you want to stay with the same kind of tire that came with the car, or upgrade to something better (and more expensive...). Price out similar tires made by a few different manufacturers so you can find the best deal.

Tire prices vary considerably. Dealerships charge the most for tires. Service stations and auto parts stores are also expensive. Tire stores are generally expensive, but can have some good deals. Department stores have good prices, especially when they have sales. Wholesale stores and shopping clubs have even better prices. Low tire prices, and a large selection, can be found through mail order suppliers -- even after shipping charges are figured into the price.

No matter where you buy tires, buy a name brand. Low quality is the reason why unknown brands remain unknown. The major brands are -- Bridgestone, Dayton, Firestone, Continental, Cooper, General, Goodyear, Kelly, B.F. Goodrich, Michelin, Uniroyal, Armstrong, Pirelli, Centennial, Dunlop, Remington, Sumitomo, Toyo and Yokohama. Sears department stores also sell major manufacturer?s tires under the Sears brand name.

Three different charges are incurred when buying new tires. The first and the most expensive is the basic cost of the tire. Then there is a fee to mount and balance your tires. (Shop around, these fees vary widely.) There is also a nominal charge for new valve stems. Many large retail stores mount and balance tires and provide lifetime rotations and road hazard insurance for one surprisingly low fee.

Any warranty is better than no warranty, but don?t make a tire purchase based on this criteria alone. A tire warranted to go 70,000 miles might be a bad choice. Its hard rubber tread won't wear out quickly, but won't provide good traction either. Also, basic tire warranties only cover defects in workmanship and materials. It is difficult to prove that your driving style and lack of maintenance weren?t to blame for early wear-out.

Modern tires are usually not defective and do not often go flat -- "road hazard" or tire insurance is not necessary unless your car is rolling on some very expensive rubber.

Tire talk: Reading Specifications

Tire Specifications

When it's time to replace your tires, you have to know what brand and type you want, as well as their size. This information is printed on the sidewall. Brand name and tire name are easy enough to find sometimes they're even printed in raised white letters.

Tire size is measured in a combination of millimeters, letter codes and inches. The size of the tire pictured above is: P205/60SR15. The first letter is "P" for passenger tire. The first number is the tire?s width in millimeters -- in this case 205mm. The second number is its aspect ratio -- the ratio of sidewall height to width (also known as "profile"). In this case the sidewall height is 60 per cent of 205mm -- or 123mm. This tire is speed-rated, so the second letter is the speed rating -- in this case it?s "S" (112 mph).


Speed ratings give a general idea of a tire's overall performance characteristics -- a family sedan needs no more than an "S" rated tire, while a Ferrari will use a "Z" rated tire. Tires with high speed ratings are more expensive and shorter-lived than tires with low speed ratings. Speed ratings use the following letter codes:

Q	99 mph
S	112 mph
T	118 mph
U	124 mph
H	130 mph
V	149 mph
Z	149 mph & over

Speed rating

A letter imprinted on the tire sidewall which indicates the maximum speed that a tire is designed to withstand if it is properly inflated and not overloaded, for short periods of time. The speed rating appears in one of two forms depending on the marking system used on the tire. If it is present, the rating will appear as a letter preceding the construction type designator (as in P175/70HR13 or 225/50VR15) or it will appear following the load index (as in 195/60R14 85T).

All European tires carry a speed rating, ranging from A5 (a maximum of 15 mph for forklift tires) to Z (speeds above 149 mph).

Some U.S.-produced tires carry speed ratings, some do not because in this country the only requirement is that any new tire must be capable of 85 mph. The most common speed ratings are: S (112 mph), T (118 mph), H (130 mph), V (149 mph), W (167 mph) and Z (higher than 149 mph).

The ability to withstand higher sustained speeds is only one characteristic of speed-rated tires. Speed ratings are not so much a measure of speed as they are a measure of performance and quality. Generally, the higher a tire's speed rating, the better its resistance to head build-up. It will provide better wet and dry traction and stability and thus will have enhanced ability to corner, brake and accelerate. The next letter is "R" for radial construction -- a superior design to the bias ply tires of old. The last number designates the wheel diameter -- this tire mounts on a 15-inch wheel

Sometimes a load index and a speed rating are printed together following the size designation. This tire's size is: P205/60R15 85S. "85S" means that this tire?s load index is 1135 lbs. and it has a speed rating of "S." This means that four tires can safely carry a maximum weight of 4540 lbs. (4 tires x 1135 lbs.) at 112 mph. This is something most drivers never have to worry about, but here?s a sampling of some load ratings:

75	853 lbs.
85	1135 lbs.
88	1235 lbs.
91	1356 lbs.
93	1433 lbs.
105	2039 lbs.

Some light truck tires use a different sizing system.

This tire's size is LT 31X10.5R15. The first two letters stand for "light truck." The first number is the tire?s diameter in inches -- in this case, 31-inches. The second number is its width in inches, 10.5-inches. The "R" stands for radial. The 15 designates wheel diameter -- this tire is made to fit on a 15-inch wheel.

The very small type on the tire's sidewall contains the following information:

Uniform Tire Quality Grades are also printed on the sidewall. These grades are a result of government mandated tests that measure tread wear, traction and temperature resistance. The actual testing and grading is done by the manufacturer, so take these ratings with a grain of salt.

Tread wear measures how long the tread should last compared with a reference standard of 100. A tread wear rating of 400 means that the tread wears four times as well as the standard. This grade is only accurate for comparing tires within a certain brand.

Traction is a measurement of a tire's ability to stop in a straight line on a wet road. The highest grade is AA; A is good; B is intermediate; and C is the worst.

Temperature measures a tire's ability to withstand the heat build up caused by prolonged high speed driving, under inflation, or overloading. The highest grade is A; B is intermediate; and C is the worst.

M + S: Means the tire has the minimum required mud and snow traction.

Maximum Load: Maximum weight that the individual tire can support -- shown in pounds or kilograms.

Maximum Inflation Pressure: Shown in psi (pounds per square inch) or kPA (kilopascals). Never inflate your tires over the maximum inflation pressure.

D.O.T. Serial Number: Shows compliance with Department of Transportation regulations along with the coded name of the tire manufacturer and the place and date of manufacture. The date of manufacture is shown by the last three digits of the serial number -- Because rubber can dry out and deteriorate, tires that are extremely old can be more prone to failure than newer tires.

Tire Construction: Shows the number and type of plies (interwoven belts) which make up the tire's tread and sidewall.

Tire talk: Kinds of Tires

No tire can handle every road condition and driving style perfectly. Positive attributes are always offset by negative factors, as the following list of tire types shows:

All-Season Tires: The Jack-of-all-trades of the tire world, and, as a result, they're the most compromised. They provide only adequate traction and handling, but they have long tread life and a smooth, quiet ride. They're also relatively affordable.

Touring All-Season Tires: These tires combine good handling with a civilized ride. Their performance oriented construction means that they?re somewhat noisier and harsher than regular all-season tires. They're also more expensive than regular all-season radials, but last just as long. Some manufacturer?s arbitrarily add "touring" to a tire?s name as a selling point.

Performance Tires: Wider tread and lower profiles combine good looks with good grip for precise, high-speed driving. Performance tires tend to have a harsh, noisy ride, relatively poor wet traction, bad snow traction, and they wear out faster than all-season radials. They?re also much more expensive. The price of ultra-high performance tires can cause your jaw to drop.

Conventional Snow Tires: Have chunky, aggressive treads that dig down to pavement covered by snow and ice. They?re noisy and handle poorly on dry roads. They're more expensive than all-season radials. They should last a long time, especially since they're only on the car for one season each year. Studded snow tires have tiny metal studs embedded in the tread for even better traction. (These days snow tire use is less common than in past decades. If you live in a place where it snows, and you drive a rear-wheel drive car, invest in a set of snow tires.)

"High-Tech" Snow Tires: Have precision engineered tread patterns and state-of-the-art multi-cell compounds which lend to good ice/snow traction and stopping ability. They can be used all year, but they?re noisy and somewhat clumsy on dry pavement. They're expensive and wear out quickly.

Light Truck Tires: Specifically designed for trucks and sport-utility vehicles, yet they are as diverse as passenger car tires. "Highway ribbed," on-road tires emphasize civilized ride and handling, while aggressive "off-road" or "mud tires" have a loud, harsh ride and sloppy handling on pavement. Light truck tires are more expensive than passenger car tires due to their larger sizes, higher load ratings and heavy-duty construction. Deep treads mean that they'll last a relatively long time.

There are a variety of specialty tires:

Rain Tires: Have a drainage channel in the tread that directs water away from the tire's surface more efficiently than conventional drainage grooves.

High Flotation Tires: Big, wide tires that people put on 4x4 trucks and sport-utilities so they can drive on the sand without sinking. These tires have poor traction in the ice and snow, so put those skinny, un-cool tires back on the truck for the winter.

Directional Tires: Have a "one-way" tread pattern optimized for the direction the tires rotate on the car.

Asymmetrical Tires: Combine multiple tread patterns in order to make a more well-rounded performance tire.

Self-Sealing Tires: Have a flexible inner-lining that seals around an object if punctured, stopping air loss.

"Twin" Tires: This setup employs two thin, "half-width" tires which are mounted on a special wheel. If one tire goes flat, the other "half" can still support the car.

"Run-flat" Tires: Use special rubber compounds and reinforced sidewalls that can support the car even when deflated -- allowing limited travel.

"Lifetime" Tires: Last for many years, as the name suggests. These tires wear out very slowly while delivering adequate traction.