Control arms or "A" arms are the component which connects the spindle/brakes with the frame. There are usually an upper and a lower. The lower arm is the big one, which supports the weight of the front end through a spring or a torsion bar. The lower arm is where the actual lowering takes place in the CALMAX systems. This is done by moving the spring perch down and the lower ball joint (which attaches in the spindle) up relative to each other and the frame. The upper control arms attach to the spindle through the upper ball joint (in the spindle) and to the frame through shaft or pivot points. The upper arm has no influence on ride height but has a great deal of influence on alignment. Alignment is its primary function outside of the physical connection of the suspension to the frame. Typically the upper arm can be moved in and out relative to the frame and affect the camber and caster settings of the front end. These are very important characteristics in the alignment. The ability to manipulate camber/caster and fix a "new ball joint angle" help make it possible for CALMAX systems to drop trucks so low and still be able to align to factory specs. The lower arm on some trucks (F150) have a slight bit of alignment adjustment available, but that job is almost single-handedly done by the upper arms. The original equipment control arms are typically stamped steel parts with rubber pivots. Some of the newest trucks are sporting cast aluminum arms with rubber pivots. DJM's CALMAX control arms are all made from seamless DOM tubing and feature urethane pivot bushings with DJM's exclusive "twin tube sleeves". Urethane is a great material to make bushings from. It is heat resistant, weather proof, and most importantly is very hard and will not deflect or "squish" during stress. Rubber tends to "squish" or move during hard cornering or braking which causes your control arms to
actually move or wander a bit which throws off alignment and upsets handling. Urethane stays rock hard so your front end isn’t moving around on your while your driving. It has one nasty side effect though - It can squeak to high heaven if pinched or over tightened. That where the "twin tube" sleeves come in. They are two inner pivot sleeves, the innermost is slightly longer than its mate so when you tighten up the pivot point during installation your don’t "over tighten" and squeeze the urethane. Of course using a good weatherproof grease is also a must but twin tube sleeves help to insure a nice quiet and compliant drive. The tubular design of the CALMAX arms set them apart from other methods of lowering and is style to your suspension. Often you do not have to change coil springs to get the radical drop you are looking for. By sticking with the factory spring you don’t loose any travel or have a radical change of spring rate.
Because CALMAX Control Arms are made with very specific purposes in mind, we design arms to work with factory springs and build CALMAX Control Arms to work with engineered lowering coils. For example, we have designed two different CALMAX 2” arms for the same application, one to work with the factory spring, and one to work with a 2” lowering coil to achieve a 4” drop with optimized alignment, ball joint angles, shock length, and more suspension travel than a spring/spindle combination. CALMAX Control Arm Systems allow DJM to make very custom suspension kits for almost every truck and suv on the market today. No other suspension line can make these claims, for good reason!