Bike physics are incredibly important -- for example, when you are in the air. Press [Brake] to lean your rider forward somewhat, and press GAS to lean him back. If you are going 50 mph or more in the air and are going to land on a flat surface, do not release the gas. Doing so when landing will prevent your rider from flying off as easily. It has to do a lot with the rider's and the bike's momentum. If you are attempting to land on a hill, which can be difficult, you must adapt to what part of the hill you are landing on. If you are going to land on the face, you must either hit it at the same angle, or lean back more. If you are going to hit the top, lean back so your back tire hits first.