Peter wrote:
wrote:

TO make the bicycle steer
merely from rake and trail takes a large lean angle and does not
accomplish the same effect. You don't need any esoteric URB's to test
this with your own mount although this may not sound as scientifically
complex, it demonstrates the effects strikingly.

My observations are that either effect could explain the ability to steer a
bike by making it lean by small amounts while walking so distinguishing
between them would require either constructing a frame/fork with a
different rake/trail geometry to eliminate one effect or canceling the
gyroscopic force to eliminate the other.

May I suggest an experiment? The second gyro wheel is a bit
difficult to set up, although it could probably be done with a
long solid axle, a BMX axle peg, and a small second wheel. However
changing the steering geometry should be easier for the pushing-the-bike
experiment. For extra trail, one can reverse the forks. For
the negative trail setup (extra rake), one does not need a
setup robust enough to ride, just to push. An extra front hub
clamped in the forks and a couple of pieces of sheet metal to
extend the rake forward could do it. For god's sake don't try
to ride it though.