J&M Motorsports - 07-11 Mustang Shelby GT500 & 05-10 GT J&M Motorsports Billet LCA

2005-Pres. Mustang Street Aluminum Billet Lower Control Arms

The control arm bushings found in the Mustang automobiles can have a significant impact on the vehicle’s ride, comfort, handling, acceleration, noise and vibration. When the car leans (i.e., rolls) in a turn, one side of the chassis moves upward relative to the rear axle, the other side moves downward, and the control arms must twist to allow for the axle to articulate. This causes the control arm bushings to bind. If this bind becomes excessive, it will raise the rear wheel rate and produce sudden, uncontrolled, undesirable changes in handling (e.g., snap oversteer).

Ford minimizes this suspension bind by using compliant rubber bushings in both lower control arms. These relatively "soft" bushings help accommodate the necessary motion of the control arms during body roll. However, the rubber bushings do not provide much in the way of forward and aft support, which can cause wheel hop during hard acceleration and braking.

It has become common practice to replace the stock rubber control arm bushings with solid or two piece polyurethane bushings to resolve the shortcomings of the soft rubber bushings. Hard polyurethane bushings eliminate wheel hop, reduce axle deflection, and improve rear straight line grip. However, the downside of common aftermarket bushings such as delrin, steel, stiffer rubber, solid or two piece polyurethane bushings is they prevent the necessary movement of the control arms during body roll, which in turn produces significant binding in the suspension when the vehicle is cornering. The polyurethane bushings also place unnecessary high stresses on the torque boxes, which are the attachment points for the control arms to the chassis. Standard aftermarket control arms do not allow for rotation of the control arm during cornering because of the stiffness of the bushings.

The Solution:

J&M Products designed and built a Billet Aluminum lower control arm which will eliminate the unwanted uncontrolled control arm flex. Machined using 6061-T6511 grade aluminum which is heat treated and stress relieved for superior strength. We also designed the control arm to have generous radiuses on all the critical edges to eliminate unwanted stress risers along with no machined windows which will make the arm weaker.