None of the early designs seemed to have any brakes, making them quite impractical.
Without modern steel and machined parts, a bicycle of wood and iron would simply be too heavy.
None of them were freehub designs, so you could always backpedal to slow down. It's definitely more work than a real brake, but it's not nothing.
The penny-farthing was a direct drive on the front wheel - no chain. It had you positioned on top of the wheel to get as much traction as possible.
A primitive recumbent trike would tend towards the same design, like a child's trike, with no chain and a direct drive on the front wheel.
And because you'd get terrible traction, with so little weight, you'd be dead in the water until the machining was available to engineer a chain system to connect pedals in front of the cyclist with wheels underneath. I don't think there's any penny-and-two-farthings intermediate to make the recumbent trike work before that.
I’d go so far as to say no cyclist understands. AFAIK there’s no simple physical explanation.
When I started riding motorcycles, I bought a well-known motorcycling book. It had a whole chapter on countersteering because there are even today many seasoned motorcyclists who don't believe or understand that you turn using countersteering.
The actual question is "Why, when you give a bicycle a good shove, does it stay upright on its own, continually changing its direction to balance itself?"
It's well known in motorbikes that the amount of rake is what makes a bike more stable vs more responsive to steering. Some folks lower the front of the bike - tighten the triple tree lower on the forks - to increase responsiveness on otherwise more boring bikes.
Of course there's more to it all, gyroscopic effects and so on, but this is the countersteering perspective.
There's more stuff here: https://calfeedesign.com/geometry-of-bike-handling/
As you can see from the simulation, this is a multibody dynamics problem. The bicycle and human have lots of moving parts, and as they move there are forces in 3D [2] amongst them. So there can't really be a simplified, short and mostly complete English explanation (like for why planets go around the sun). That doesn't mean we can't predict.
[1] https://www.comsol.com/blogs/simulating-the-motion-of-a-self...
[2] i.e. you can't find a 2D plane in which all forces act.
> Their study shows that there isn’t one simple reason for this phenomenon. A combination of factors, including gyroscopic and caster effects, bicycle geometry, speed, and mass distribution come into play to keep an uncontrolled bicycle upright.
I think we’re saying the same thing. There is no simple physical explanation that humans can intuitively understand, because the interaction of forces is so complex. I’m not claiming that it’s a mystery causing fundamental problems for physics.
So don't say "no astrophysicist understands stellar reactions" because that is false. They understand fully, and can write the model and simulate it to answer any question.
Ditto for bicycles. Just because there is no simple explanation for bicyles does not mean we don't fully understand the physics of bicycles. It just can't be put in English. Only in complex mathematical models.
Cyclists are not exactly the equivalent of "astrophysicists" in this situation though. There are of course physicists who are also cyclists, but basically no cyclist who is not (or isn't very interested in the field) would be able to explain it.
This is probably a case where not being a scientist was an advantage. Turns out they didn't need a simulation or mathematical proof it could work in order to try it.
However, on the question at hand, it mostly says:
>Bicycle stability can’t be explained using just one or two mechanisms. It’s a combination of many different intertwined factors, like the mass distribution of individual components, size of the tires, geometry of the frame, and others. [...] What keeps bicycles balanced with or without a rider is still an active area of research, and even the seemingly basic idea that, for a bicycle to be self-stable, it needs to turn the handlebars into the fall, has not yet been proven.
There is no mention of air resistance at all. Does it play a role in (de)stabilizing the vehicle in higher speeds? Would a bicycle work as well in, say, lunar vacuum (I imagine that it would be hard to pedal in spacesuit, but let's assume a spherical cow and a lunar bicyclist in normal clothes). Would a lunar bicycle be more stable at lower speeds because of the lower gravity on the Moon?
Back when I used to do my commute with e-scooters, indicating my direction was a real pita and, most of the time, totally impossible. In fact I used to use the sidewalk and pedestrian crossings if I needed to go left through the traffic.
Understanding the physics is not a requirement to operate the vehicle.
The rider turns the bike by moving the handle bars slightly in the opposite direction he wants to turn. Then the bike falls in the direction he wants to turn, and the handle bars are then rotated in that direction. To straighten out, the handle bars turn a little tighter, and the centrifugal force of the turn pushes the bike back upright.
Definitive explanation? Yes - to a significant degree of definitive. As with all science/engineering-understanding there are always further details but this we've got pretty well down at the macro level humans operate at.
A site beloved by HN to explain this: https://ciechanow.ski/bicycle/
A beautiful site, check out the archives for other explanations and animations of things too.
There's more to it than just Newtonian mechanics.
Also, horses are the original self-driving transportation, and anyone with the means to buy some newfangled technology like the early bicycle. It's been a hundred years and we're still not better in that regard than the finest of equine hybrid technology, so can you imagine the landed gentry giving that up to... Exert themselves to travel to town?
(Queue 'bicycle as feminist icon' comments below)
Landed gentry often love showing off their wealth in ecentric ways, so yes i could imagine that.