Yet if you are on the rear brake when a mini-stoppie or stoppie DOES happen, the rear wheel will stop. A motorcycle stays up mostly due to two gyroscopes: the front wheel and rear wheel. If you are in a stoppie and the rear wheel stops moving, the bike is going to want to flop to the left or right along the steering head, as the main gyroscope which wants to keep the rear in line with the front will no longer be spinning. Owch.
