Suspension/Alignment

How do you know if your car needs an Alignment?

Sometimes the answer to this question is easy. If your car is pulling to one side or the tires are wearing in an unusual way, you need to look at you suspension system. An alignment is the proper adjustment of the car's front and rear suspension. The suspension system has two basic functions, to keep the car's wheels in firm contact with the road and to provide a comfortable ride for the passengers. A lot of the system's work is done by the springs. Under normal conditions, the springs support the body of the car evenly by compressing and rebounding with every up-and-down movement. This up-and-down movement, however, causes bouncing and swaying after each bump and is very uncomfortable to the passenger. These undesirable effects are reduced by the shock absorbers.

Suspension / Alignment Terms

Shock Absorbers

In the past, a wide variety of direct and indirect shock absorbing devices were used to control spring action of passenger cars. Today, direct, double-acting hydraulic shock absorbers and shock absorber struts have almost universal application.

Coil Springs

Compression type coil springs may be mounted between the lower control arm and spring housing or seat in the frame. Other front suspension systems have the coil springs mounted above the upper control arms, compressed between a pivoting spring seat bolted to the control arm and a spring tower formed in the front end sheet metal.

Leaf Springs

Front leaf springs are used with solid axle beams in most truck applications. Corvettes use single-leaf, filament-wound, glass/epoxy front and rear springs mounted transversely

Torsion Bars

Torsion bar suspension uses the flexibility of a steel bar or tube, twisting lengthwise to provide spring action. Instead of the flexing action of a leaf spring, or the compressing-and-extending action of a coil spring, the torsion bar twists to exert resistance against up-and-down movement.
Adjusting the torsion bars controls the height of the front end of the vehicle.

Shock Absorber Struts

A strut is a structural piece designed to resist pressure in the direction of its length. On typical "MacPherson Strut" use, the shock absorber is built into the strut. Most shock absorber struts are hydraulic units.
Sway Bar

Some cars require stabilizers to steady the chassis against front end roll and sway on turns. Stabilizers are designed to control this centrifugal tendency that forces a rising action on the side toward the inside of the turn. When the car turns and begins to lean over, the sway bar uses the upward force on the outer wheel to lift on the inner wheel, thus keeping the car more level.

Control Arms

A control arm is a bar with a pivot at each end, used to attach suspension members to the chassis.

Toe
Toe, simply put, is direction the wheels are pointing. Zero toe would be perfectly parallel wheels pointing straight forward. Toe-out means the front of the tires are farther apart than the rear of the tires. Toe-in means the front of the tires are closer together than the rear of the tires.

Camber
Camber is the lean of the wheel. If the top of the wheel tilted away from the car, that is called positive camber. If the top of the wheel is tilted in towards the car, that is called negative camber.

Caster
Lots of positive caster is like the forks on a chopper; the wheel is far in front of the support for the wheel. Less positive camber as like the forks on a regular street bike, the wheel is only slightly in front of the support for the wheel. Caster will not affect tire wear, but it can cause a slight drift if it's not equal on both sides. Caster is an angle that only applies to the front (steering) wheels of a car.