Abstract
It is shown by eigenvalue analysis that the weave mode, which is one of the vibration modes affecting the straight running stability of the motorcycle, becomes unstable as the speed becomes higher. In this report, we clarify the mechanism of high speed instability of weave mode. From the analysis results of the Energy Flow Method, it was found that the main cause of the instability in the high speed region is the phase delay of the rear tire lateral force term. Furthermore, it turned out that the root cause of the phase delay is an increase in the vehicle speed.
