Control arms are the main part of automotive suspension. Through a ball joint and silent blocks (track control arm) they connect the wheel with the chassis. They are guiding the wheel by keeping a knuckle in the right position. They also prevent the wheels from moving forwards and backwards, allowing the car being kept on the right track when driving. They have direct influence on the safety of driving and comfort of driving.
Classic track control arms are similar in look to triangles, but resulting from various constructions of the system, they are also sometimes a straight (longitudinal) element, the so-called trailing arms.