When your mechanic performs an alignment, several factors are checked. If the tops of the wheels angle in toward the vehicle, this is referred to as negative camber. If the tops angle away from the vehicle, it is a positive camber. When properly adjusted, the camber angle keeps the outside tires flat and stable on the ground during a turn. Improperly adjusted camber will result in improper handling and tires that wear out prematurely.
Caster refers to the angle of the vertical axis of the wheel in relation to the steering connection.
A higher caster angle gives greater stability at high speeds, but steering may be more difficult at lower speeds. A lower caster angle results in more ease in steering, but the vehicle may wander at higher speeds. Properly adjusted caster allows the wheels to track in a straight line and prevents shimmy. Toe refers to the front end of the wheel. Factory specifications for camber, caster and toe are established for every vehicle and should be followed exactly.