Kerry McLean’s V8 powered Rocket Roadster monocycle which crashed in 2001, crashed as a direct result of an unusual principle know as a torque-induced precession ‘Gyroscopic Precession’.
The wheel itself, which had been hand-made, was not a perfect circle and was essentially an unbalanced wheel. Once Kerry reached high speeds the vibrations caused by the unbalanced wheel caused him to enter into a gyroscopic precession, from which he could not recover.
I found the following videos very interesting and cool in how they explain the principles behind what causes gyroscopic precession.
I hope you enjoy!