Not everyone is familiar with the terminology associated with wheel alignments. While you may not find it necessary to become acquainted with terms such as camber, caster, and toe, it is beneficial to understand the workings of these three major alignment parameters. Proper wheel alignment is essential to maintaining vehicle and tire longevity, while also ensuring that your ride is both safe and comfortable.
Camber is the angle of the wheel relative to the vertical of the vehicle, and depending on the tilt, is either considered positive camber or negative camber. When the top of the tires tilt away from the center of the vehicle you have positive camber, and when the top of the tires are tilted inward you have negative camber. One isn't better than the other, but varying camber angles have different effects on your vehicle.
Depending on the type of vehicle that you drive, a little positive or negative camber can be useful, but too much of either is both dangerous and bad for your tires. All vehicle manufacturers will provide exact specifications for appropriate camber. Technicians will use these angles to properly align the camber. If you think that your vehicle is due for an alignment, you can (call the store for an appointment).
Caster is the angle that identifies the forward or backward slope of a line that is drawn through the upper and lower steering pivot points. It does not affect tire wear, but caster does have an influence on the directional control of the steering. Caster angle settings allow manufacturers to balance steering effort, high speed stability, and front end cornering effectiveness.
Positive and negative caster mainly apply to race cars, and unless your vehicle is lifted or customized in some way that calls for an adjustment, street cars usually run on factory determined settings.
Toe is a measurement that determines how much the front and/or rear wheels are turned in or out from a straight-ahead position. The amount of toe, whether it's toe-in or toe-out, is expressed as the difference between the track widths as they are measured at the leading and trailing edges of the tires. Toe is expressed in degrees or fractions of an inch, and while your wheels should be pointed directly ahead as you are traveling straight forward, there are some benefits to toeing depending on the type of vehicle that you drive.
The purpose of toe is to ensure that all four wheels roll parallel to one another. However, race cars use toe-out to promote enhanced turning ability. Street cars, or basic passenger cars, use toe-in because there is no need to corner quickly. Toe-in also provides increased stability because it discourages turning. If your vehicle has the proper amount of toe you should experience ideal straight line stability, corner entry, and very little tire wear.