Wheel alignment is important to the health of your car or truck. All of the elements that make your car go straight are called “alignment”.
If you hit a big pothole, for example, it is possible to bump alignment components out of their carefully calculated locations, throwing out your balance and suspension.
Some shops try to make it seem like rocket science, but wheel alignment is a fairly straightforward affair. The inclusive term “wheel alignment” involves three main measurements — caster, camber, and toe. These measurements have standards that a technician uses as targets of adjustment.
In other words, get as close as you can to the right measurement. The good news is that most modern cars only have adjustments for toe.
Caster is the tilting of the uppermost point of the steering axis either forward or backward (when viewed from the side of the vehicle). A backward tilt is positive (+) and a forward tilt is negative (-). Caster influences directional control of the steering. When the rear of the vehicle is lower than its designated trim height, the front suspension moves to a more positive caster. If the rear of the vehicle is higher than its designated trim height, the front suspension moves to a less positive caster. With too little positive caster, steering may be touchy at high speed and wheel returnability may be diminished when coming out of a turn. If one wheel has more positive caster than the other, that wheel will pull toward the center of the vehicle. This condition will cause the vehicle to pull or lead to the side with the least amount of positive caster. Caster is the tilting of the uppermost point of the steering axis
Camber is the tilting of the wheels from the vertical when viewed from the front of the vehicle. When the wheels tilt outward at the top, the camber is positive (+). When the wheel tilts inward at the top, the camber is negative (-). The amount of tilt is measured in degrees from the vertical. Camber settings influence the directional control and the tire wear. Too much positive camber will result in premature wear on the outside of the tire and cause excessive wear on the suspension parts. Too much negative camber will result in premature wear on the inside of the tire and cause excessive wear on the suspension parts. Unequal side-to-side camber of 1° or more will cause the vehicle to pull or lead to the side with the most positive camber.
Camber is the tilting of the wheels from the vertical when viewed from the front.
Toe is a measurement of how much the front and/or rear wheels are turned in or out from a straight-ahead position. When the wheels are turned in, toe is positive (+). When the wheels are turned out, toe is negative (-). The actual amount of toe is normally only a fraction of a degree. The purpose of toe is to ensure that the wheels roll parallel. Toe also serves to offset the small deflections of the wheel support system that occur when the vehicle is rolling forward. In other words, with the vehicle standing still and the wheels set with toe-in, the wheels tend to roll parallel on the road when the vehicle is moving. Improper toe adjustment will cause premature tire wear and cause steering instability.