Two-mass-skate bicycle

[1][2][3] The two-mass and skates aspects of the model were chosen to eliminate design parameters so that the nine that remain, the locations of the masses and the steering geometry, could be more easily analyzed.

[1] In 1970, David Jones explained in Physics Today how he experimented with a traditional bicycle to see if cancelling the gyroscopic effect of the front wheel would make it unridable.

"[4] Finally, he made a bike with negative trail, by adding forward extensions to the ends of the fork, and found that it had negligible self-stability and was "indeed very dodgy to ride, though not as impossible as [he] had hoped.

They conclude: As a rule we have found that almost any selfstable bicycle can be made unstable by mis-adjusting only the trail, or only the front-wheel gyro, or only the front-assembly center-of-mass position.

Conversely many unstable bicycles can be made stable by appropriately adjusting any one of these three design variables, sometimes in an unusual way.A physical example has been created that closely approximates the TMS model and exhibits self-stability without gyroscopic effects from the wheels and without positive trail.