Are struts simply oversized shock absorbers?

A strut performs the same ride control functions as a shock absorber, but it is also an integral part of the suspension rather than an add-on component.

On most strut suspensions (except some late model Honda applications that have "wishbone" suspensions), the struts replace the upper control arms and ball joints.

The 1986 Honda Accord has a rear double-wishbone suspension. The strut plays no role in wheel alignment in this arrangement, serving only to carry the vehicle's weight and to dampen shocks.

Struts serve as the steering pivots and on most applications (except certain Ford suspensions like the Mustang and T-Bird), they also carry the springs. On some rear-wheel drive strut suspensions, the wheel spindles are part of the front struts (which adds to their cost). The same is true on some front-wheel drive rear strut applications.

Another important difference between struts and shocks is that struts also affect wheel alignment, whereas shocks do not. A bent strut or a mislocated strut tower can cause tire wear and steering pull problems.

Many struts are also rebuildable. On many import cars, the struts have an internal cartridge or wet elements that can be replaced by unbolting the upper strut mount, swinging the strut out from under the fender, disassembling the upper strut components, and replacing the internal components with a new cartridge.

On most domestic applications, however, the entire strut must be replaced. Replacement options include both nonpressurized and gas pressurized versions, the latter offering all the same benefits as gas shocks.

One often overlooked strut component that usually needs attention is the upper bearing plate that sits atop the strut. This plate supports the weight of the vehicle and serves as the upper pivot point for steering. If corroded or worn, it can make noise, increase steering stiffness and reduce steering returnability.