A good-quality tire gauge

A tire shop or service station that you can trust

Axle: the long metal rod that the wheel revolves around.

Camber: as you look at the wheel from the front, camber is the angle between a vertical line, and a line drawn through the center of the tire.

Caster: as you look at the wheel from the side, caster is the angle between a vertical line and a line drawn through the center of the steering axis .

Toe: as you look at the wheels from above, toe is the angle between a line through the center of the vehicle, and lines drawn through the centers of the tires .

Valve stem: a flexible rubber finger with metal threads on the end, that sticks out from the wheel rim. It's the point where you add or release air from the tire.

PSI: Pounds per Square Inch is a standard way to measure air pressure in many instances, including tire pressure.

Front-wheel drive: a vehicle that is propelled by the front wheels, which are driven by the engine. The rear wheels roll behind passively.

2torial #0518: Learn2 Understand Tire Care Oh baby, don't blow out on me! Tires are, well...tires. It's tough to get as excited about them as, for instance, an all-expenses paid trip around the world. All the same, if you and your friends or loved ones will be driving around on them, there's some routine maintenance that you should do or have done. The tires will last longer, the vehicle will ride more smoothly and quietly, and the trip will be safer for your passengers and other vehicles on the road. Follow the guidelines and your tires will sing hymns of praise and gratitude to you. You can do some tire maintenance yourself, but you'll need to take your auto to a decent shop for other work. You'll probably find that prices (and the services included in those prices) vary widely in your area. Shop around, but consider this: if a friend can recommend a good shop, or you know of a well-established place with a good reputation, it's worth paying a little extra to have the job done properly. Understand tire balancing, wheel alignment and tire rotation   There are three important services that an auto repair shop can do for your auto: balance the tires, align the wheels, and rotate the tires. The first two don't need attention that often; tire rotation needs to be done little more frequently. Balancing: No matter how well a tire is made, it's probably going to need a little help to spin correctly--i.e., without wobbling. Generally a mechanic does this by attaching small weights to the wheel rim; this offsets any irregularities in tire or rim construction. Balancing can be done with the wheel on or off the vehicle, but most times it's taken off.   When you first buy a tire and have it mounted, it should be balanced as well. As the years go by, and the tire wears down, it may need to be balanced again. A noticeable vibration in the vehicle is a good indication that a tire needs balancing (or something else is wrong--find out now!). Wheel Alignment: Picture a hoop around your waist, and imagine that it's a wheel and tire combo on an axle. If you can imagine the different ways that a hoop could shift position around your waist-- forwards, backwards and side-to-side--then you have an idea of how a wheel and tire can shift around on the end of your axle. Alignment makes sure that the wheels and tires are in the correct position in relation to your vehicle, and each other. This should be done when tires are bought and mounted on the vehicle. Camber, Caster and Toe are what need to be adjusted here. These terms are in Keywords if you're curious, but they're not essential for you to know. Just make sure the mechanic knows!) An auto manufacturer will specify precise reset values that the mechanic can look up and use to set your wheels up correctly. Due to better design and manufacturing, some vehicles stay in alignment better than others. But unless you're four-wheelin' on dirt roads, your vehicle will need to be aligned only once or twice a year. How do you know if the vehicle is out of alignment? Keep an eye on your tire tread: if the tread is wearing unevenly, take the vehicle in before the tire is seriously damaged. Another clue: while you're steering straight ahead, the vehicle has a tendency to veer to one side or the other. This may also be fixed with alignment work. In any case, there are generally two kinds of alignment offered: regular, and four-wheel or thrust-angle. If you have a vehicle with fully independent suspension, you'll need to spend the extra money to have all four wheels aligned. It's also a good idea to have four-wheel alignment on all front-wheel drive vehicles (see Keywords). Rotation: Tires wear at different rates on your vehicle. Depending on your make and model, some wheels power the vehicle, other wheels steer it, and some wheels are just along for the ride (loafers!). To get the longest wear from your tires, and to help them wear at the same rate, it's necessary to switch their positions every once in a while. Most tire companies recommend rotation as often as convenient, around every 6000 miles or so. Indeed, if you're counting on that 30,000-70,000 mile warranty that comes with most tires, you'll need to keep records of tire rotation to collect on it. At the least, it's a good idea to rotate your tires every 10,000 miles. In particular, front-wheel drive vehicles need regular rotation.   Tire rotation can be done a few different ways. Some auto manufacturers want the tires to go back and forth on the same side of the vehicle, while others specify a criss-cross type pattern. If you look in your owner's manual, you'll find out what the manufacturer recommends. Do your own maintenance Tires don't require a lot of everyday maintenance. The two main strategies are to keep them inflated to the proper pressure, and to protect from the elements. They'll last longer, ride better, and be less likely to blow out. Tire pressure: The trickiest part of checking your tire pressure is that you actually have to check it twice: once before the vehicle has been moved that day, and again when you're at a gas station with an air hose. The first reading is from a cold tire, and it's the accurate one, while the second is from a tire that has warmed up from rolling on the pavement. The second reading will be a bit higher than the first. Here's the routine: Get a good quality tire gauge, and measure the pressure in all four tires before you move the vehicle. You'll do this by removing the plastic caps on your valve stems (see Keywords) and pressing the gauge firmly down over the metal threads on the end of the stem. You'll hear a little hiss as a bit of air escapes, but when you press the gauge firmly down and hold it there, the noise will stop and the gauge will register the tire pressure.   Write down the measurement for each tire--this is your cold measurement. Tire companies specifications reflect cold tire pressures, and pressure is measured in PSI, or Pounds per Square Inch.   The auto manufacturer has specified tire pressures for both front and back tires. Look for these specs on the inside edge of the driver's door, on the inside of the glove compartment door, or in the owner's manual. Use these numbers, rather than the numbers printed on the outside of the tire, to find out how much pressure should be in the tires.   Compare the cold measurements with the manufacturer's pressure recommendations. If the manufacturer recommends a different pressure (either higher or lower) than the cold measurement, you'll adjust the tire pressure accordingly.   Find a service station with an air hose. Sometimes you'll need to put a coin in to make it work, but in most places there won't be any charge. There will either be a metal handle that releases air when you squeeze it, or a simple metal fitting that releases air when it's pressed over the valve stem.   Take the tire pressure again with your own tire gauge. It'll probably be a bit higher than the cold measurement, since the tire has warmed up from rolling along the pavement. This will be the warm measurement.   If the cold measurement was lower than the manufacturer's recommendation, add the proper amount of air with the hose. How much? Use the warm measurement as your guide. Let's say you compare the cold measurement (say, 32 PSI) with the manufacturer's recommendation (35 PSI)--the tire needs three more pounds of pressure. If the warm measurement was 34 PSI, fill up the tire until the gauge reads 37 PSI. Don't worry if the final measurement is more than the manufacturer's recommendation--tomorrow morning, when the tire is cold again, the pressure will be correct.   On the other hand, if the cold measurement was higher than the manufacturer's recommendation, release the excess pressure from the tire. (This is easy to do: find the valve, and press on the metal piece in the center of the valve with your fingernail, a key, or a small stone, until your hear a hissing sound.) Again, use the warm measurement as your guide. For example, if you knew from your cold measurement that the tire had two pounds of excess pressure, and the warm measurement is 38 PSI, release pressure until the gauge reads 36 PSI.   Tires lose pressure at different rates. If you measure tire pressure every few weeks or so, you'll get a better idea of how often adjustments are necessary. Don't try to go by the tires appearance, as modern radial tires often look under inflated when they're not.   Overly inflated tires can wear unevenly, so don't try to overinflate them into balloons. Tire protection: The tire's rubber compounds can dry out and crack just from daily exposure to sun, water and road salt. There are quite a few pump-spray rubber and vinyl dressings on the market now, and they work well on tires. Some of them are even marketed specifically for tire care.   Buy any one of the pump sprays which says that it protects rubber against UV exposure and follow the directions in applying it. Use it on the side of the tire, not the tread. If you apply the stuff three or four times a year, chances are that you won't wind up lots of little cracks in the side of the tire, and the tire will have a better shot at reaching a ripe, old age on your vehicle. -end- Learn More!