A bike remains upright when it is steered so that the ground reaction forces exactly balance all the other internal and external forces it experiences, such as gravitational if leaning, inertial or centrifugal if in a turn, gyroscopic if being steered, and aerodynamic if in a crosswind.
Do motorcycles balance on their own?
When the bike slows down to a stop, or when it’s traveling slower than 4 kph, the angle of the fork changes and brings the front wheel forward. This action activates the self-balancing system that makes small left and right adjustments to the wheel in order to balance the bike.
Why do motorcycles not fall over?
In short, leaning the bike allows there to be a gravitational torque to balance the torque from the fake force. Leaning prevents you from falling over.
