Yellow pivot cup. The pivot cup is the rubber component housed on the outer part of the baseplate. Similar to bushings, the pivot cup needs to be in good condition to fulfill its function, which is to assist the truck in faster and smoother self-centering. It also protects the pivot area every time you perform a trick or turn the trucks. Without it, over time, the tip of the hangar would wear down until it breaks or reduces in size, impeding the proper functioning of the truck.