Control arms are one of the most boring, yet mechanically impressive parts on a car. In the most basic of terms, the control arms allow up and down movement of the suspension while holding the knuckles, spindles, and axles firmly onto the car. They have been an integral part of suspension systems for nearly a century. Over this time, they have come in a variety of shapes, sizes, and materials but they have always served the same exact function - to hold everything together!