Fuckin magnets
How do they work?
For those that don’t know: Bill O’Reilly Doesn’t Understand How Tides Work
Gyroscope effect. You ever do the experiment where you spin a bike tire really fast and then try to tilt it? Shit’s nuts.
That only causes part of the effect, most of it is the bike’s steering countering the momentum of your fall.
You wouldn’t be able to balance on a bike with just the wheel spinning, you’re too heavy. That is why bikes on those indoor rollers allow the bike to move left and right a bit.
Just like orbiting something. Satellites are constantly just falling back to earth, but with enough grace to always miss earth. I bet satellites would be great cyclists!
That’s always fun. Some people will swear it can’t possibly work like that, but they have plenty of experience riding bikes. You wouldn’t be able to turn properly at speed unless you’re counter-steering, so they clearly have done this. The idea seems to be so incredibly intuitive that people don’t even realize they’re doing it, which is very interesting.
The gyroscopic effect of slowly spinning, light bicycle wheels is negligible compared to the weight of the bike and it’s rider. If it was what keeps you upright, riding a tiny scooter-thing with skateboard/inliner wheels would be impossible. I mean those without motor, pedals, where you push yourself forward with one foot on the ground), often for kids.
What actually keeps you upright isn’t a physical effect, but just training your brain to instinctually keep you upright. While you’re moving, turning the handlebar effectively moves the bike below you left and right. So if you start tilting to the right, you turn right (slightly) so the bike/scooter is moving below you to compensate. That’s why learning to ride anything that is balancing on 2 wheels takes a relatively long time, but only once. Then your brain knows what to do, and it just works without thinking about it.
But then, why would they be more stable when moving, even without a rider? If the steering is tight enough, you can push a bike to someone a good distance away. You can do it with a scooter too, although it’s a lot harder.
You can also look at a motorcycle. Their mass is far greater than a human’s, a person could never manage that. Those little RC motorcycles are the same, they don’t need some crazy balancing system to mimic humans, they just need to stay upright enough to get some speed going, then they balance themselves.
It’s the same with a wheel - the speed makes it stay upright, they can balance on the tiniest edge so long as they’re moving
It’s not a gyroscopic effect either, though that’s present. It’s a balance between rotation speed and the friction with the ground - the object as a whole has momentum, the rotation has momentum, and the contact with the ground balances the two. It’ll try to put it’s center of mass in line with these forces acting on it
Add in a human, and they can shift the center of mass on the fly. The vehicle’s speed is still pushing you upright - get on a bike with some good speed, and you can lean very far into a turn and ease off to return upright. Way more than you could if it wasn’t moving
Normal bikes that you just push aren’t that stable without a rider, but you can get it some distance. They still fall over rather quickly. That’s mostly the form of the handlebars like gnu commented. And yes, without a rider, the gyroscopic effect is relevant. A bike weighs let’s say 15 kg, and a rider is commonly like 75kg. Of course removing like 80% of the weight changes if the gyroscopic has a meaningful influence. Add the rider back, and it becomes negligible again.
This is of course even more pronounced if you push only a wheel with nothing else, then there’s nothing left but momentum and the gyroscopic effect.
The reason you lean into a turn is exclusively the centrifugal force (not sure that’s the right twin), if you don’t you fall over because you have nothing to turn against. Changing direction needs something to push against.
Brah just discovered conservation of angular momentum
It’s not that. Gyroscopic action exists of course, but it’s fairly weak against the weight of your body. Balancing a bicycle is just like balancing an umbrella on your finger, except you can easily move your finger any direction you need. To move the bicycle sideways, you need to already be moving forward.
Track stands! Not a contradiction to your statement at all though: you need to be moving just ever so slightly.
With a fixie it’s easy, because you can pedal forwards and backwards in tiny amounts. With a freewheel, it’s trickier but you get the hang of it with practice. Ideally you’ll have an incline, so you pedal forward to go forward, and ease up to slide back. After some practice I can use the raised reflective paint from e.g. crosswalks as the “incline.” This miniscule motion is enough to balance — and like you said, it ain’t the angular momentum that does it.
it really is that though, have you not done the rotating wheel experiment? it is fucking hard to tilt the axis of a wheel rotating at a speed which is comparable to biking speed. come to think of it maybe not:
first, and less importantly, your wheels are gyroscopes
second, and much more importantly, at speed you use your steering to compensate for imbalance. You lean a little right? slight steering to the right compensates. When standing still, steering is no longer an option (duh)
It has as the sole cause. But when you have a couple big spinny bits, there is going to be some gyroscopic effect, and it does help keep it upright. It just can’t on its own, it provides a small assist.
It’s the central pedal force