control arm. The vertical pseudo-macpherson arm moves through a non-linear pathway at its connection to the hub; its "base" at the connection to the wheel hub is moving along an arc of r = tension rod L.
Something has to give; the upper control arm can only move within a 1-D axis.
The upper control arm is rooted at the unibody; it is constrained solely to 1D motion.The vertical arm moves along an arc at its connection to the hub, which results in a 2D motion at its connection to the upper control arm. There is a bearing at the connection between the vertical arm and the hub which allows for a DOF within the steering plane, but it does not accommodate for a DOF between the tension rod arc and the upper control arm arc. In the OEM design, the FUCA has readily flexible rubber bushings to accomodate for this 2D motion. The design of these new arms, even despite containing what appears to be a polymeric bushing support, will focus this second DOF into the threaded coupling and force such a rigid structure (stud/twin locknuts) to yield. One of the two locking nuts at the center "stud" of the upper control arm will be forced to loosen. Whichever one of the two is tighter will prevail. This will require one end of the stud's threads to act as a bearing to the second DOF. With the stresses induced within this part during heavy braking and the limited surface area the threads within the loose end of the stud offers to handle the load, it may result in a structure that becomes "wobbly".... prematurely... If a FUCA were to be designed using this new part as a base but also allowed a rotational DOF through the centerline of the stud, it would be a correctly designed aftermarket component..... imho...
Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the
tailor.
Albert Einstein
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