Commonly Located: Normally, struts are found on utility type ATVs (as opposed to sport quads). They are located in the front of the ATV and are attached to the frame and spindle.
Physical Description: The strut is normally a cylindrical shape with a spring around the outside. It is similar in appearance to a shock. The strut attaches to the ATV frame by a single stud sticking out of the top. The bottom of the strut will be bolted to the spindle.
Note that while shocks and struts LOOK similar, they are actually not the same. For reference, see the Anatomy of an ATV post on shocks.
Function: The ATV strut allows the suspension to flex both up and down, affecting the ATV's ride quality and handling. The struts also contribute to the ATV's weight carrying ability. The presence of ATV struts replaces the need for the upper control arm.
Maintenance Costs: The ATV strut is a not a common wear item unless it is abused; i.e., lots of racing/jumping or commonly used for heavy loads. For this reason, it is usually safe to purchase a used strut; however, the buyer should use discretion.