WHY CORRECT WHEEL ALIGNMENT MATTERSCorrect wheel alignment serves a number of functions. It helps the vehicle handle and steer properly, helps maintain optimal tire wear, helps maintain proper fuel economy and prevents premature wear from occurring in steering and suspension parts.
WHAT IS WHEEL ALIGNMENT?In a nutshell, wheel alignment is the process of making sure all four wheels are aligned at proper angles relative to your vehicles design and suspension layout. Each make and model vehicle has specifications that the manufacturer sets for the positioning of the wheel on three axis' known as caster, camber, and toe.
The illustration to the right shows each of these three definitions. Starting with Toe, if we were to look down at the wheel from directly above it, the toe angle would be the angle at which the front or back of the tires are pointed towards or away from each other. Think about someone who walks pigeon toed. This would be the same as the front tires of a vehicle having a positive toe angle. In most cases a minor amount of positive toe is desireable (usually less than .3 degrees) to help with steering responsiveness. Having too much positive or negative toe can severely impact shoulder wear on the edges of your tires, or possibly even feathering across the entire tread area of the tire.
Camber can be thought of as the angle of the top of the tire towards the center or away from the center of the vehicle if we were looking at the tire from directly in front of it. If the top of the tire leans in towards the center of the vehicle, the camber angle is considered to be negative. Again, a minor amount of negative camber is usually considered desirable to improve vehicle stability while cornering. Consider a vehicle that has a positive camber problem. That would indicate that the top of the tire is leaned out away from the center of the vehicle. As you begin to corner, that angle is going to increase in most suspension systems which can create the sensation that the tire is trying to roll underneathe the vehicle as you turn. Camber can also contribute to severe shoulder wear on your tires if the angle is excessive, and can also contribute to the vehicle pulling to one direction when you let go of the steering wheel.
Caster is the final angle we're concerned with and usually the most difficult for people to understand. In simple terms, caster is the angle at which the steering knuckle (that your wheel bolts to) is positioned relative to the front or back of the vehicle. If the top of the steering knuckle is pointed towards the back of the vehicle the angle is considered to be positive which is desirable. Think of a motorcycle for a moment. The way that motorcycle steering forks angle back towards the rider make the steering very stable. Now think if we were to reverse that angle so that the handlebars and rider were positioned out in front of the tire. The steering would become very darty and difficult to maneuver. The same applies to cars and trucks. The more that positive angle is decreased, the dartier the vehicle becomes and the less the steering wheel wants to return to center on it's own after exiting a turn. Caster angle is also a major contributor to vehicle pull.
HOW DO YOU CORRECT BAD ALIGNMENT?We have a piece of equipment that hooks up to all four wheels of your vehicle to measure these angles. Once we've determined which angles need to be adjusted to meet manufactureres specifications we can adjust them using the adjustment points that are built into your vehicles suspension and steering systems. Occassionally a vehicle will not come equipped with adjusters for certain angles, usually caster and/or camber. In these cases aftermarket kits are usually available to make these angles adjustable. It is very important that vehicle owners not try and change these angle themselves as the tolerances between a proper alignment and one that will wear tires or make the vehicle handle poorly are often only a fraction of a degree.
Courtesy Tire recomends getting an alignment done at least once a year with the road conditions we have in most areas of seattle and it's surrounding suburbs.