With 4 bar suspensions being quite popular among mini-truckers and hot-rodders throughout the United States, shops and individuals have designed and installed many various configurations. Some of which are very good designs, and some of which are poor designs, that get the job done. There are two main types of configurations; parallel, and triangulated. Many mini-truckers choose the triangulated type, mainly for ease of install; whereas, many drag racers choose the parallel configuration, for ease of adjustability. As Adams describes in his book Chassis Engineering, the axle is held in place with the control arms of the 4 bar suspension, and the placement of the control arms provide for different characteristics, so there are many potential configurations (69). "Both styles of 4 link accomplish the same thing... very simply, they hold the rear axle in the vehicle. The function of a 4 link is to keep the rear axle in its proper place under the vehicle. The bottom 2 links keep the axle in place front to back. The upper 2 links keep the axle from rotating, keeping the pinion angle as constant as possible" (Air Ride Technologies).

A parallel 4 bar suspension has two sets or rods that run from the axle to the frame in front of it (Remus). These 4 bars hold the axle in place, and locate it under the frame. Unfortunately, this type of design allows the rear end to move side to side in reference to the frame of the vehicle because the rubber bushings in the bars allow for flexing. This means that some type of locating device is needed. The most simple is called a panhard rod, or panhard bar. This bar runs from the chassis on one side of the vehicle and connects to the axle on the other side of the vehicle (Fish). The panhard bar prevents the axle from moving laterally all over the place as the vehicle is being driven down the road.

One of the large advantages of a parallel 4 bar kit is the fact that it is available from many aftermarket companies, and they are fairly inexpensive as well, due to their availability. Another advantage to these systems is the ease of adjustment. It is very easy to simply unbolt a rod, adjust it as needed, and bolt it back in place and change the characteristics of the suspension to perform as desired under certain conditions. If installed properly (its hard not to install it properly), this system will provide a "good ride" and "good handling" (Remus).

A commonality between both parallel type configurations and triangulated configurations is that both use lower control arms that are parallel to one another. The difference between the two comes with the upper control arms. A triangulated 4 bar link system has two upper links, which instead of being parallel to each other, are angled. They can angle from the frame towards the center of the axle, or from the center of a cross member between the frame, to the edges of the axle. Either of these setups will work quite well. "When viewed from above, these rods form a triangle" (Remus). The positive side of having a triangulated 4 bar suspension is the lack of a need for a lateral locating device. The triangulated upper links absorb the lateral forces that the axle places upon them throughout the turns that the vehicle makes, as well as while driving in a straight path hitting bumps.