Top-mounted bicycle frame: also known as roof-mounted bicycle frame, it has the advantage of being able to carry bicycles while driving fast, professional, safe and stable, and is popular with bicycle clubs and professional athletes. The disadvantage is that after the bicycle is fixed on the roof of the car, the height increases significantly, and the trafficability will be affected to a certain extent; The most stable and safe overhead bicycle frame in the world adopts the design of double arms.