A strut is a self-contained assembly consisting of a shock, a coil spring, a top plate, and a mounting plate or bearing plate. A shock is just that, a shock. A strut is load-bearing, which is why it contains a spring, but a shock works next to a spring and does not support any vehicle weight. Regular shocks and strut replacements play a vital role in your vehicle's safety, performance, suspension component wear, tire wear, and even the distance in which your car can stop — this is why it is so important to maintain them.

For example, in a McPherson strut suspension, the strut replaces all the suspension components except for a lower control arm or wishbone. The strut turns with the wheel left and right and can do this because it has a bearing mounted on top of the strut called a bearing plate.