Actually bicycle gyrospoic affects are quite negligable Mark. You'll promptly discover this if you try to ride onto ice with a bicycle. It'll fall down just as quick as you please. Even a motorcycle, which is spinning a much heavier wheel at a much higher rpm, has negligible stability contribution from the gyroscopic affects of the wheel spinning. The rpms are far too low for it to be significant.

What does significantly affect the stability of both bicycles and motorcycles is rake and head angle, and center of gravity. Which is why you can ride some bicycles and motorcycles at a walking pace with no hands. Why do you think performing cop shows are done using Harleys? :-)

> Grab a bicycle wheel by the ends of the axle, and have someone
> spin it (they'd be lucky to get 5mph surface speed at tire) and then
> try to abruptly change the spin axis. There are other factors at work
> as well, I'm sure, but gyro affects are not negligible.