At this time, the bike is being flipped rapidly from side to side, and if it has a large trail, it will wobble as it does so because the front wheel will turn with the lean. Some Other Factors. There are other factors besides trail which affect a bicycle's steering. Many people assume that the gyroscopic action of the front wheel is solely responsible for keeping a bicycle upright. In fact, its effect is minor.
Gyroscopic stability is what keeps a rolling hoop from falling.
One can demonstrate the gyroscopic forces on a bicycle wheel by holding a detached, still wheel by the ends of its axle. Tilt the axle up and down, without letting it twist left or right. In other words, put one hand higher than the other without letting either hand move forwards or back. Then spin the wheel forward, and tilt it again. When the axle is tilted so that the left side is down, it will twist left, and when it is tilted with the right side down, it will twist right.