...how the bicycle works?

General cycling advice ( NOT technical ! )
tim-b
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...how the bicycle works?

Postby tim-b » 27 Dec 2013, 5:40am

Hi
A Christmas Conundrum for you...

http://www.newstatesman.com/science/201 ... ycles-work
http://www.sciencemag.org/content/332/6027/339

Regards and Happy Cycling in 2014
tim-b
~~~~¯\(ツ)/¯~~~~

PJ520
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Re: ...how the bicycle works?

Postby PJ520 » 28 Dec 2013, 4:59pm

Neither of these articles has any hint as to why I fall of my bike in dark tunnels with very little light and no headlight, a situation I've found myself in a couple of times. It was like when I was first learning to ride: wobble, wobble, wobble, crash. In fact the links suggest that if anything I should just keep pedaling and I'll stay upright. My guess is that riders need a visual reference to maintain balance. Am I the only one this has happened to?

I must add that I have rode through a 2 mile long tunnel with a headlight with no problems at all.
You only live once, which is enough if you do it right. - Mae West

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531colin
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Re: ...how the bicycle works?

Postby 531colin » 28 Dec 2013, 6:33pm

Pete Jack wrote:Neither of these articles has any hint as to why I fall of my bike in dark tunnels with very little light and no headlight, a situation I've found myself in a couple of times. It was like when I was first learning to ride: wobble, wobble, wobble, crash. In fact the links suggest that if anything I should just keep pedaling and I'll stay upright. My guess is that riders need a visual reference to maintain balance. Am I the only one this has happened to?

I must add that I have rode through a 2 mile long tunnel with a headlight with no problems at all.


Sighted people use visual clues as an aid to balance. **
I don't know if its true, but long ago I was told the old Air Force test for balance for flight crew was to stand on one leg with your arms folded and your eyes shut for 3 minutes.
Bicycles when pushed and let go will continue for a while.....but the self-stability of a bicycle weighing a few pounds will not balance a man weighing several stones sat on top of the bicycle.

** mis-match between visual clues and actual balance is the basis of motion sickness

rualexander
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Re: ...how the bicycle works?

Postby rualexander » 28 Dec 2013, 6:52pm

Video from the people who carried out the research referred to in the links in the OP :
https://youtube.googleapis.com/v/YdtE3aIUhbU?hd=1

cycloret
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Re: ...how the bicycle works?

Postby cycloret » 28 Dec 2013, 7:27pm

Bikes remain upright because of the gyroscopic effect of the wheels? Utter tosh? Try telling that to someone doing track stands in a velodrome, or me in my childhood having slow bicycle races with my friends. To ride a bike you need a sense of balance which is aided by sensory input from the middle ears, visual cues and sensory proprioreception.

That's not to say that the gyroscopic effect has no effect when you're on a bike. It's just not the whole story from the off.

Jughead
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Re: ...how the bicycle works?

Postby Jughead » 28 Dec 2013, 7:38pm

Tim B. You bored? :D

mercalia
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Re: ...how the bicycle works?

Postby mercalia » 28 Dec 2013, 7:53pm

is due to a number of factors - the qyroscopic effect of wheels + forward momentum ( hence slower u go the more unstable ) + balance of rider

Ayesha
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Re: ...how the bicycle works?

Postby Ayesha » 28 Dec 2013, 8:43pm

“researchers are developing something called the Anaconda. It’s never going to be much of a speed machine because it is, in effect, a chain of monocycles with handlebars. These units are connected, by means of hinges that allow them to snake along, to a normal two-wheeled bike at the front. Every rider in the chain can be going in a slightly different direction, which means it takes an enormous amount of control and collaboration to move the thing forward.”

“The idea is to unleash it as a beach-resort bike, the kind of thing that stag and hen parties will use to terrorise seaside towns across the world.”


Alcohol + Anaconda = busy night for A&E.

Ayesha
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Re: ...how the bicycle works?

Postby Ayesha » 28 Dec 2013, 8:48pm

Next thing you'll hear is they made it into a Broadway show.

'How bicycles work,,, the musical...'

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gaz
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Re: ...how the bicycle works?

Postby gaz » 28 Dec 2013, 11:03pm

There are eternal mysteries upon which the mind of man is not meant to ponder.

The poetry of a bicycle in motion should not be reduced to mathematics.

mark a.
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Re: ...how the bicycle works?

Postby mark a. » 28 Dec 2013, 11:25pm

cycloret wrote:Bikes remain upright because of the gyroscopic effect of the wheels? Utter tosh? Try telling that to someone doing track stands in a velodrome, or me in my childhood having slow bicycle races with my friends. To ride a bike you need a sense of balance which is aided by sensory input from the middle ears, visual cues and sensory proprioreception.


The paper (not the Anaconda) is talking about riderless bikes i.e. if you just push and let go of a bike, it will probably stay upright for a while until it slows down too much. Naturally a skilled rider can do all sorts of weird things to keep bikes upright - BMX flatlanders being an extreme case.

The full paper, videos etc can be found here. We discussed it (with input from one of the authors) here.

It tickles me that something as "obvious" as gyroscopic forces and trail being necessary for bike stability is not necessarily true. It doesn't really matter too much in the real world (bike builders have had plenty of practice to make bikes stable) but it's fun to see what happens when you actually look into it.

tim-b
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Re: ...how the bicycle works?

Postby tim-b » 29 Dec 2013, 6:39am

Hi mark.a

Your summary works for me
It tickles me that something as "obvious" as gyroscopic forces and trail being necessary for bike stability is not necessarily true. It doesn't really matter too much in the real world (bike builders have had plenty of practice to make bikes stable) but it's fun to see what happens when you actually look into it.


"Nothing compares to the simple pleasure of a bike ride." John F. Kennedy, former U.S. President

Regards
tim-b
~~~~¯\(ツ)/¯~~~~

reohn2
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Re: ...how the bicycle works?

Postby reohn2 » 29 Dec 2013, 9:55am

gaz wrote:There are eternal mysteries upon which the mind of man is not meant to ponder.

The poetry of a bicycle in motion should not be reduced to mathematics.


Which makes me glad I'm not a mathematician :) and even happier that I can just pedal and go :D
-----------------------------------------------------------
I cycle therefore I am.

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Claireysmurf
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Re: ...how the bicycle works?

Postby Claireysmurf » 29 Dec 2013, 10:09am

I rarely chat to other people when I am cycling as I am constantly amazed that I can balance. :lol:

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Mick F
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Re: ...how the bicycle works?

Postby Mick F » 29 Dec 2013, 10:09am

I was musing the other day about my first foray onto two wheels having been on three wheels since I was big enough to reach the pedals.

My three-wheeler much like this one mid 1950's:
Screen shot 2013-12-29 at 10.03.18.png
Screen shot 2013-12-29 at 10.03.18.png (163.57 KiB) Viewed 1331 times


We kids would race round the local pavements and roads on our bikes, and after I'd managed two wheels for a while, I got out my old three-wheeler for "old time's sake". They all said I couldn't go back on it and I wouldn't be able to steer, I denied I'd have a problem. How right they were, and how wrong I was! :oops:

There was no way I could steer the thing at any useful speed. I'd become so used to leaning and balancing, that turning the 'bars and not being able to lean, left me going almost straight on!

I never went back to the three-wheeler again.
Mick F. Cornwall