Say your rear wheels are tilted to the right. Even if your steering wheel is pointed straight, your vehicle will travel left. Four-wheel alignment solves this problem by referencing all four wheels to a common centerline. Camber is the inward and outward tilt of the wheel at the top. Toe is the difference in distance between the front and back of the front or rear tires.
Caster is the backward or forward tilt at the top of the spindle support arm.
Your steering system controls the direction of your vehicle, while your suspension system supports the weight of your vehicle. Though they have different jobs, your suspension and steering work together to do many things - control the vehicle, steer straight, get good, even tire wear , provide a smooth passenger ride and insure safe vehicle control.