Last experimental report, I promise (crossing fingers behind back). I'll describe what I did and challenge people to predict the outcome.

As mentioned, when I earlier rode down the street with the bike tilted to the left, and me positioned way over to the riight to counterbalance, the bike tended to "pull" in the direction it was tilting ie. left, requiring me to apply constant pressure to the handlebars in the opposite direction just to keep the bike going straight.

In this setting, the front wheel has angular momentum around its axle. Now the ground is also applying upward pressure to the side of the tire, and that could be interpreted as lateral torque (around the axis defined by my jousting lance, if I had one, ie straight ahead). However, the wheel is not falling to the left, presumably because my body is leaning to the right and this translates into a counter-rotational force being applied to the wheel at the front dropouts to keep it at the angle it is at. Thus, there is no net lateral torque being applied that would make the wheel want to veer left. The veering force, I believe, is caused by the gravitational effect at the fork..if the wheel turns left, the bike's centre of gravity drops slightly, so gravity is trying to make the bike turn left. As well, a camber steering effect may also be in place.

So what is my experiment? If angular momentum (gyro) is important at keeping a bike stable, then at high speed, the rapidly spinning front wheel should increasingly resist the turning force created by gravity and camber steering, and it should get much easier to maintain a straight ahead course while tilted, without having to keep pushing so hard on the left side of the handlebar.

So, I rode along a very slow pace, with the bike tilted as described, and my left hand and arm applying a steady push on the left handlbar to keep the bike going straight ahead. Then, I cranked the bike up to a much higher speed, still at the same tilt.

So, everybody, did "gyro" kick in and could I relax my left arm a bit?


Answers will be posted tonight.

Robert