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Wouldn't that imply that a bicycle wheel I roll down the street by itself should fall over immediately which clearly is not the case?
by ajmurmann 2y ago
Wouldn't that imply that a bicycle wheel I roll down the street by itself should fall over immediately which clearly is not the case?
- aidenn0 2y agoThere's not zero gyroscopic force, just negligible compared to the moment of inertia (with the tyre/ground interface as the axis of rotation) of the bike/rider system. Furthermore you will notice a bicycle wheel rolling down the street often won't roll in a straight line (as it starts to tilt sideways, it will turn to bring the contact patch back underneath it), so even with just the wheel, the gyroscopic stabilization is insufficient on its own to keep it upright.
- Levitating 2y agoNo that's not true. A bike just naturally steers into its fall. Veritasium made a video about it: https://youtu.be/9cNmUNHSBac?si=8cbWXgoqg-uuVidb https://youtu.be/9cNmUNHSBac?si=8cbWXgoqg-uuVidb
- powersnail 2y agoA bicycle is not the same as a bicycle wheel though. I can't just roll down a bike down the street (at least not as easily as a single wheel); it almost always immediately falls over.
- bityard 2y agoSure you can. At very low speeds, yes, the bike will fall over. But a bike with some minimum amount of speed can roll upright on its own just fine. You can try it yourself with your least favorite bike and an empty parking lot. All it takes is a good solid push. It has to do with bicycle frame geometry and center of mass. Neil deGrasse Tyson explains it in this video at 2:52: https://www.youtube.com/watch?v=RIrgwWQqqts https://www.youtube.com/watch?v=RIrgwWQqqts
- Gh0stRAT 2y agoThat's not countering the argument that steering is what is preventing the bike from falling over rather than the gyroscopic effect of the wheels. You'd have to tie off the handlebars with a static line before rolling it in order to prove that it was the gyroscopic effect keeping the bike upright.
- ajmurmann 2y agoI can ride my bike easily without touching the handlebars at all once it's rolling.
- merlynkline 2y agoTry that with the handlebars tied immovable. Or actually, please don't.
- powersnail 2y agoI actually tried a it a lot when I was young, and it never worked even on a downward slope. Maybe I was too weak back then, but again, the point is that a full bicycle doesn't have the same behavior as a standalone wheel, which is very easy to roll, and pretty much stands on its own until its speed is really really low.