We still don’t really know how bicycles work
Hat tip: Jalopnik
Science Has No Clue How Bicycles Really Work
http://jalopnik.com/science-has-no-clue-how-bicycles-really-work-1040770947
That sends readers here:
We still don’t really know how bicycles work
http://www.newstatesman.com/2013/07/mysteries-bicycle
Forget mysterious dark matter and the inexplicable accelerating expansion of the universe; the bicycle represents a far more embarrassing hole in the accomplishments of physics.
By Michael Brooks Published 06 August 2013 11:21
....
It is rare that most people appreciate the bicycle, but it is quite an extraordinary machine. Push a riderless bike, letting it roll freely at high enough speeds, and it can withstand pushes from the side – it will wobble a little, but quickly recover. In the conventional analysis, that is because the gyroscopic force of the front wheel, its mass and the spontaneous turn of the handlebars all act together to keep the bicycle rolling forwards. This has something to do with the gyroscopic effect, the force that keeps a spinning top upright. You can feel this by removing a wheel from your pushbike and spinning it while you hold the axle spindles. If you try to change the orientation of the wheel, you’ll feel it push back against you.
The first mathematical analysis of bicycles suggested that this is also what keeps a moving bike on its wheels. But although the equations were written down in 1910, physicists always had nagging doubts about whether this was the whole story.
The most definitive analysis came exactly a century later. It involved an experimental bicycle that had all its gyroscopic effects cancelled out by a system of counter-rotating wheels. The effort of building such a strange contraption was worth it: the resulting paper was published the prestigious journal Science.
The publication plunged bicycle dynamics back into chaos. It turns out that taking into account the angles of the headset and the forks, the distribution of weight and the handlebar turn, the gyroscopic effects are not enough to keep a bike upright after all. What does? We simply don’t know. Forget mysterious dark matter and the inexplicable accelerating expansion of the universe; the bicycle represents a far more embarrassing hole in the accomplishments of physics.
The research was done by mechanical engineers. Every mechanical engineer I know is into motorcycles, bicycles, or firearms. The article is two years old, so the issue can't be that big a quandary.
A Bicycle Can Be Self-Stable Without Gyroscopic or Caster Effects
http://www.sciencemag.org/content/332/6027/339
Science 15 April 2011:
Vol. 332 no. 6027 pp. 339-342
DOI: 10.1126/science.1201959
A Bicycle Can Be Self-Stable Without Gyroscopic or Caster Effects
J. D. G. Kooijman 1, J. P. Meijaard 2, Jim M. Papadopoulos 3, Andy Ruina 4,* A. L. Schwab 1
Author Affiliations
1 Department of Mechanical Engineering, Delft University of Technology, Delft 2628 CD, Netherlands.
2 Department of Engineering Technology, University of Twente, Enschede 7500 AE, Netherlands.
3 Department of Engineering and Technology, University of Wisconsin–Stout, Menomonie, WI 54751, USA.
4 Department of Mechanical Engineering, Cornell University, Ithaca, NY 14853, USA.
*To whom correspondence should be addressed. E-mail: ruina@cornell.edu.
Abstract
A riderless bicycle can automatically steer itself so as to recover from falls. The common view is that this self-steering is caused by gyroscopic precession of the front wheel, or by the wheel contact trailing like a caster behind the steer axis. We show that neither effect is necessary for self-stability. Using linearized stability calculations as a guide, we built a bicycle with extra counter-rotating wheels (canceling the wheel spin angular momentum) and with its front-wheel ground-contact forward of the steer axis (making the trailing distance negative). When laterally disturbed from rolling straight, this bicycle automatically recovers to upright travel. Our results show that various design variables, like the front mass location and the steer axis tilt, contribute to stability in complex interacting ways.
= new reply since forum marked as read
The planet Brontitall is a planet visited by the crew of the Heart of Gold in the Secondary Phase of the Radio plays. It is notable for three things:
Its primary lifeform is an Avian/Humanoid hybrid that has not set foot on the ground for endless years.
The entire surface of the planet is covered with a dry crumbly substance that is not stone, rock, or some other form of dry crumbly rock or stone that the reader is heretofore unacquainted with, but long-since decayed and disintegrated shoes.
A 15 mile-high statue of Arthur Dent throwing a styrofoam coffee cup.
The statue was created in the distant past of the planet as the population was about to reach the Shoe Event Horizon. A freak wormhole opened in the vicinity of Mr. Dent as he was berating the Food generator computer on the Heart of Gold on the poor quality of its beverage service. The sight of a man striking back at technology inspired the citizens of Brontitall to get rid of all of their robots, sending them all to a distant planet to make continent toupees for planets that have used up all their forests.
The Statue was the last great thing built by the people of the planet before they evolved into birds. The giant marble cup floats in mid air, held aloft by the Power of Art. Since it is artistically correct for the cup to be where it is, there it remains.
You would simply have 2 gyroscopes on the same axis of rotation, without it mattering which way they rotated, just that they were rotating gyroscopes 
There is no net angular momentum in a system of equal counter rotating gyroscopes hence no net gyroscopic force.
