With the main bar in place, we then fitted the main hoop of the cage. This hoop should be as tight to the roof of the car as possible without interfering with the headliner if your car is so equipped. Since our car will see race duty only, we won't run a headliner. In either case, however, the driver's head/helmet should never be above the main hoop while in driving position. Once in position and level, tack the main hoop in place.