Unicycle advice..

[pjclinch]

This is probably egg-sucking for grannies 101, but it can help if you've grokked the balance model for forward motion. As Brucey notes, you're inherently unstable in all directions, and unlike a bike you have to mix and match the instabilities to go forwards, not just to stay up side-to-side. If you sit up straight and the cycle goes forwards, you'll fall off backwards: you have to lean in to your direction of motion. The more oomph, the more the lean. Find yourself falling forwards, speed up, if you're going over the back, slow down. It's a bit like steering in to a fall to balance a bike, but with speed variation rather than turning.

Pete.

[Brucey]

.... A bike essentially has only one axis of (unstable) rotation ... .

it arguably has zero unstable axes, once in motion; were it not so, a bag of potatoes would not be able to 'ride a bicycle'.

BTW I agree the brain is a fantastic learning machine, but there are easy ways of learning stuff and hard ways of learning stuff; too much of the latter and folk are wont to 'learn/practice failure' or simply get cheesed off with the whole thing.

cheers

[Geoff.D]

.... A bike essentially has only one axis of (unstable) rotation ... .

it arguably has zero unstable axes, once in motion; were it not so, a bag of potatoes would not be able to 'ride a bicycle'.

BTW I agree the brain is a fantastic learning machine, but there are easy ways of learning stuff and hard ways of learning stuff; too much of the latter and folk are wont to 'learn/practice failure' or simply get cheesed off with the whole thing.

cheers

I definitely do agree, Brucey, that a properly set up bike is not difficult to master. But it does still have an unstable axis. The bag of potatoes doesn't actually "ride" the bike. It remains upright until some of the conditions that keep it upright get out of kilter and....over it goes. A person on the bike is continuously monitoring these conditions (essentially where the C of G is at any one time) and making micro adjustments to bring the conditions back into kilter. The techniques include pressure on the pedal; movement of bum on saddle; pressure on the handlebars; body position when honking uphill; and (probably the most important) slight variations of steering.

I'm not convinced that prior knowledge of these factors (and certainly not an action plan of how to apply them) is useful in learning to ride a bike/unicycle. Thinking about, and trying to calculate, the amount of steering change needed as one begins to fall sideways just isn't effective. The experiential approach is the easiest for this sort of activity.

This is different, of course, to any advice as to the conditions in which it's best to experience and practice. Most of us above have suggested moving from the hall, to an open space with the ability to mount with a handhold, preparing the right crank position, to getting onto wider vistas. But, all of us have said that at some point you have to launch out and try it. One revolution leads to two, and then three........and so on.

Obviously the experiential approach isn't the easiest learning path for every task. Learning to mend a puncture needs a mixture of information/explanation first, followed by practice. Sometimes demonstration is the easiest way, such as being shown where the saddle clamp bolt is in order to adjust height.

I agree with you that it's horses for courses. Different learning paths are more appropriate (you might say "easier") for different tasks, and people for that matter.

As you say the brain is a fantastic learning machine. But, strangely enough, it's also its own worst enemy on occasions. 661-Pete mentioned those bikes that are engineered to steer in the "opposite" direction. Once the brain has got to the point of intuitively steering in one way at the time of learning to ride (and subsequently reinforced) it's really, really, really difficult to "unlearn" this. More difficult, in fact, than were we introduced to this type of bike right from the beginning.

Trikes.............a packet of solutions on three wheels !!!!!

[Brucey]

sorry, you appear to be working on a different definition of stability to the rest of us. A (well designed) bicycle is inherently stable. You can peturb it in motion, at which point it will self-correct and carry on. The primary source of 'instability' in a bicycle is usually.....

... the rider....

A unicycle is completely different to that, and this discussion isn't really germane to the thread or helpful to the OP in any way.

If you want something really unstable, try one of these;



cheers

[Geoff.D]

sorry, you appear to be working on a different definition of stability to the rest of us. A (well designed) bicycle is inherently stable. You can peturb it in motion, at which point it will self-correct and carry on. The primary source of 'instability' in a bicycle is usually.....

... the rider....

A unicycle is completely different to that, and this discussion isn't really germane to the thread or helpful to the OP in any way.

cheers

You may well be right that you and I are using a different definition of stability. But that certainly doesn't include "the rest of us", who really haven't engaged in this particular argument.

I accept that a powered, riderless, bike bike can travel a long way in a straight line on a smooth, regular surface and is inherently stable under these conditions. I've seen the video. However, the real world of cycling isn't quite like that. Velocity has a part to play, too, and is a key ingredient in the inherent stability. With a rider aboard, and irregular surfaces (potholes, tramline type constraints, cambers, slow speeds, etc) , he/she does counter balance changes in conditions that would make it unstable, EVEN WHEN those changes are caused by the rider him/herself as you say.

However, I do disagree with you very strongly that the discussion isn't "germane to the thread or helpful to the OP". My point hasn't changed throughout. Learning to ride a bike is best done through experiential learning, not analysis. Similarly, learning to ride the much more complex set of skills involved in riding a unicycle is also best done experientially. This is quite germane to the OP's first post where he asks "Where to start". Of course it's only my opinion (and my personal experience) that experiential learning is appropriate, but it is a direct answer and germane to the OP's question.

With regard to it being "unhelpful" to the OP, I would suggest that only he can make that statement. Unless you have had private conversations with him about this, I believe you are using this phrase in the same way as using "...to the rest of us". They are phrases to undermine my opinions, but neither of have validity in this context.

[Brucey]

I'm sure we all have slightly differing views on many things but 'stability' is a term that is well understood in engineering circles. A bicycle is directed using inputs into a system that is inherently stable; a unicycle is not.

A similar arrangement is used in most aircraft; the controls are trimmed to (say) level flight and the system is inherently stable when perturbed, just like a bicycle is.

In both cases the control inputs are perturbations that simply direct/change where the whole thing is pointed, rather than, (from moment to moment) prevent instant disaster because the system is otherwise inherently unstable, which is more akin to how a unicycle behaves.

Equally I am sure that we all learn how to do things in slightly different ways. However couching the learning experience in terms of abstractions that might only make sense post hoc isn't necessarily going to be terribly helpful to someone who hasn't been through that process yet. By contrast some suggestions of what and how to practice are the kinds of things that are likely to be more useful to most people.

By analogy if (say) you want to use a gun, you will obviously only get any good at it if you spend time practising. But you will only spend your time well if someone tells you a good way to practice, and more importantly if you are not told the basics (like which end is which) you might blow your head off in the meantime.

Similarly history shows very clearly that if you don't understand what you are doing when (say) learning to take off/land in an aircraft, it will take forever to become even remotely proficient, and then only if you don't kill yourself in the meantime.

So in the first instance I would always favour concise and accurate suggestions for methods that are known to work, together with some explanation of the mechanics involved, certainly over vague post hoc abstractions.

cheers

[Geoff.D]

I'm sure we all have slightly differing views on many things but 'stability' is a term that is well understood in engineering circles. A bicycle is directed using inputs into a system that is inherently stable; a unicycle is not.

A similar arrangement is used in most aircraft; the controls are trimmed to (say) level flight and the system is inherently stable when perturbed, just like a bicycle is.

In both cases the control inputs are perturbations that simply direct/change where the whole thing is pointed, rather than, (from moment to moment) prevent instant disaster because the system is otherwise inherently unstable, which is more akin to how a unicycle behaves.

Equally I am sure that we all learn how to do things in slightly different ways. However couching the learning experience in terms of abstractions that might only make sense post hoc isn't necessarily going to be terribly helpful to someone who hasn't been through that process yet. By contrast some suggestions of what and how to practice are the kinds of things that are likely to be more useful to most people.

By analogy if (say) you want to use a gun, you will obviously only get any good at it if you spend time practising. But you will only spend your time well if someone tells you a good way to practice, and more importantly if you are not told the basics (like which end is which) you might blow your head off in the meantime.

Similarly history shows very clearly that if you don't understand what you are doing when (say) learning to take off/land in an aircraft, it will take forever to become even remotely proficient, and then only if you don't kill yourself in the meantime.

So in the first instance I would always favour concise and accurate suggestions for methods that are known to work, together with some explanation of the mechanics involved, certainly over vague post hoc abstractions.

cheers

This is a concise explanation of the way in which you learn, Brucey. As I wrote above, learning requires pointers of how to do something, explanations as to why and practice to acquire the skill. According to the context these will come in different combinations and emphases. Likewise for different learners. I quite accept that you prefer to have all three. Horses for course, obviously.

I learnt to ride when I was about 7 years old. I had four pointers, all gained by observation. I knew which end was the front, I knew that you pedals to power the thing, I knew what the brakes did and I could see the desired outcome (the goal). With these, I got on in our back yard and tried it repeatedly, until I was "off". I didn't need any any deeper mechanical knowledge and no understanding of the dynamics at all. I would gauge the learning as being about 90% experiential, to achieve the goal of riding upright and steering successfully.

I would suggest that most people learn in a similar way. Give them space, a pointer or two (and perhaps a steadying push off) and repeated trying will soon have being able to stay upright. Steering and stopping will follow in a similar way. Again, I think the main emphasis will be on the experience of trying it. I have no quantifiable evidence for this suggestion. I'm extrapolating from my own experience.

With regard to the inherent stability of a bicycle, I totally agree with you, as I wrote upthread. I've seen the videos of powered riderless bikes. I've also read some of the mathematical analyses about bicycle geometry, steering and associated characteristics. However, I do continue to hold the view that that there are conditions (boundaries) to the inherent stability. I think two examples demonstrate this -
1. A riderless, powered bicycle won't have inherent stability on wet ice. The self correcting force that accommodates small perturbations, such as a cross wind gust, requires friction at the contact patch between tyre and road.
2. The same bicycle isn't inherently stable at very a low velocity. The magnitude of self correcting force that accommodates a small variation in the front wheels direction of motion is dependent on the velocity (and acceleration, if present). Coupled with that the gyroscope effect is also dependent on velocity.

I think you're right that we understand the term "inherent stability" in different ways. With regard to learning to ride a bike, I'm using it to mean those factors of frame and wheel geometry, bike construction and power delivery which contribute to an inherent self correcting process which avoids the machine falling over to one side, when travelling in a straight line. Some external conditions,including substituting a rider for the fixed inert sack of potatoes, can (and do in real life situations) compromise this inherent stability.

I guess I must leave this thread with these two differences of opinion unbridged. Such is life. But, I've enjoyed the discussion

[pjclinch]

If you want something really unstable, try one of these;

Or how about...




Pete.