Garage door tracks usually consist of 4 pieces (2 vertical and 2 horizontal). The purpose of a track is to provide a roadway for the roller wheels. The vertical track is mounted to the jamb with brackets on each side of the door opening. The horizontal track is mounted to the top of the vertical track, the door jamb and the garage ceiling. The horizontal track contains a curved end called the radius. In the closed position, the door rests in the vertical track. In the open position, the door is suspended from the horizontal track.