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PostPosted: Tue Dec 07, 2010 2:21 pm 
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I didnt mention anything about stability, only suggestive in that low speed riding off-road.. bolt-up-right, is not that stable

"...but then, the religious cannot understand the heretic." - im not religious, but pure-breed atheistical.

(I suppose I'd better get on with my invention to catch people who fall off the edge of the world)

Theres an edge ?

& there IS stability to talk about in the motion of a bicycle .. if you want it to handle best, for its intended use ! :shock:


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PostPosted: Tue Dec 07, 2010 4:25 pm 
retrobike rider
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Geoff did you make it up this climb without dabbing?

http://www.vimeo.com/17165461


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PostPosted: Tue Dec 07, 2010 5:35 pm 
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Do you mean the climb right at the end of the clip?

It is quite steep with lots of loose rocks; I made it all the way up, which I guess is about half a mile altogether. I think I got snarled-up once or twice. But, despite the arthritis in my knees, which gave me quite a lot of pain, and getting puffed due to smoking too much, I rode the climb right to the top by starting again from where I stopped.

I must say that the hill looks nothing in the vid.


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PostPosted: Tue Dec 07, 2010 9:40 pm 
retrobike rider
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GeoffApps wrote:
Now, if you've read this far, try another experiment: find a long piece of material, such as a broom handle or length of wood about four or five feet long. Attempt to balance it vertically on your open palm. Tricky, but do-able. Now try the same thing with a pen. More or less impossible.

This is because the centre of mass of the broom handle is further away from your hand than the c/m of the pen.

This distance is critical; the greater the distance, the more reaction time you have to adjust the balance of the broom handle, whereas the pen has fallen over before you can react to get it into balance again.

It's the same with a bicycle: your open palm represents the ground and the broom handle/pen represents a bicycle; your movements to maintain the balanced vertical position of the broomhandle/pen represent your use of the steering to maintain balance on a bicycle.


Will a tall bike be easier to balance than a shorter one?

Common sense tells you that tall everyday objects are more likely to fall over than short things. But a moving bicycle is not an ordinary everyday object, it is a remarkable symbiosis of man and machine. The physical laws that act on the bike and rider are not the same ones that govern most ordinary objects, not even other dynamic objects like cars.

Take Geoff's pen in the palm of your hand senario, very difficult to balance yes! Try sticking a large blob of BlueTac on the top of the pen and balancing will be much much easier. Use a longer pen and it becomes easier again. But try and hold a heavy box above your head and stand still and The box will make you less stable. Walking in a circle will re-stabilise everything. We are talking about two very different types of stability here, static and dynamic.

A moving bicycle behaves like a static object and even the gyroscopic effects of ten tonne wheels rotating at high speed will not stop it from falling over. (Don't confuse the small but significant gyroscopic effects that will self-centre a front wheel when riding no-hands. The idea that these small forces can stabilise a bike is pure myth, they can barely redirect the front wheel in response to the lean of the rider).

Only with the rider in place does a bicycle become a self stabilising dynamic partnership. And like the pen and BlueTac, the higher and heavier the centre of mass the easier it is to sabilise irrespective of speed. That is why riders doing track stands arch their backs skywards.

The centre of mass of a Cleland however, is only slightly higher than that of a mountain bike but much further back. So the steering has more leverage over the mass in the same way that a long pen has more leverage over the inertia of the BlueTac.

If any ones still awake, I do have the formulae for this. Perhaps someone can explain what all the letters and squiggles mean? :roll:


Last edited by GrahamJohnWallace on Tue Dec 07, 2010 11:08 pm, edited 1 time in total.

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PostPosted: Tue Dec 07, 2010 9:45 pm 
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I think sometimes people take some things to seriuosly

if you like it..buy it..and ride the bugga

not gonna do much of that do daa-in on a p.c.


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PostPosted: Tue Dec 07, 2010 10:28 pm 
retrobike rider
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sylus wrote:
I think sometimes people take some things to seriuosly

if you like it..buy it..and ride the bugga...


Indeed :twisted:

Yes, the average punta will go with their longstanding preconceptions of what a good bike is and is most unlikely to be persuaded otherwise.

But designers need understand these issues in order to design bikes that work.

Some people who have not ridden these bikes do not believe they work. Persuading them otherwise may be futile, but understanding their valid concerns and misconceptions is important.

We may be tying to sell these bikes into a non-existent or non-receptive market.


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PostPosted: Wed Dec 08, 2010 12:07 am 
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GrahamJohnWallace wrote:
sylus wrote:
I think sometimes people take some things to seriuosly

if you like it..buy it..and ride the bugga...


Indeed :twisted:

Yes, the average punta will go with their longstanding preconceptions of what a good bike is and is most unlikely to be persuaded otherwise.

But designers need understand these issues in order to design bikes that work.

Some people who have not ridden these bikes do not believe they work. Persuading them otherwise may be futile, but understanding their valid concerns and misconceptions is important.

We may be tying to sell these bikes into a non-existent or non-receptive market.


I believe i have made solid points over my thoughts on your design. One of which is that maybe one of the reasons it has not caught on is the inherent issues that lay within (repeat) riding a bicycle bolt-up-right off-road (yawn) does anyone else do it ? (i did asked earlier)

no (any takers?)

But, please do not declare your self a heretic, in such a manner as to assume that I suffer preconceived misconceptions. I find that patronising.

& who really is taking things seriously ? I have only been challenging peoples ideas, this is a public forum, is it not ? :D there no need for " :evil: " 's ! jeeees.

Knowledge is power, power breeds ego. I'd absolutely hate to say I have one, but I am passionate about keeping my advice & opinions as impartial as possible. They are FAAAAAAAAR more open than you think.

You would be selling these bikes to a market, but it would be a niche within a niche, but I do believe it exists :)

Guys, like I said, ive only challenged your ideas, based on my experience (which is very likely something you have brushed under the carpet) that does not mean you should assume i know nothing, or what i know is not worth knowing..

Sincerely,

Cristian


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PostPosted: Wed Dec 08, 2010 1:38 am 
retrobike rider
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Cristian said...
Quote:
I believe i have made solid points over my thoughts on your design. One of which is that maybe one of the reasons it has not caught on is the inherent issues that lay within (repeat) riding a bicycle bolt-up-right off-road (yawn) does anyone else do it ? (i did asked earlier)

no (any takers?)


Cristian, you have indeed made many valuable and pertinent points and do not take any of my comments as being directed at you or even that I pigeon hole you as someone who is unwilling to consider ideas that contradict their own.
Upright off-road bikes? There is in fact a long tradition of upright off-road bikes due to this being the predominant riding position amongst everyday riders before metaled roads were commonplace. This ranges from the invention of the bicycle right through to BMX bikes and even early US mountain bikes who commonly featured raised handlebars. The tradition continues in the third world and in Germany were they have high handle bared trail bikes. Only the predominance of Tom Ritchey inspired mountainbikes in the early 80's make this style of bike appear as old fashioned and slow.


Quote:
But, please do not declare your self a heretic, in such a manner as to assume that I suffer preconceived misconceptions. I find that patronising.

I did not intend to patronise any one. We all suffer from preconceived misconceptions and the only cure is an enquiring mind and a willingness to listen.


Quote:
& who really is taking things seriously ? I have only been challenging peoples ideas, this is a public forum, is it not ? Very Happy there no need for " Evil or Very Mad " 's ! jees.


I welcome your questioning of ideas.

And whilst I find the detailed workings of the bicycle to be fascinating, it is not life and death, and I do things with a sense of humor and fun.
The "Twisted Evil" was intended to be directed at my self, not others.

Quote:
nowledge is power, power breeds ego. I'd absolutely hate to say to have one, but I am passionate about keeping my advice & opinions as impartial as possible. They are FAAAAAAAAR more open than you think.


The only sensible way to convince people that the Cleland design is valid is to let them try the bikes for themselves. Explaining them in words can at best illustrate that the design is well thought through. It is futile to fully explain these bikes in words. They are really about the senses, the physical and emotional experience of riding them.

Quote:
You would be selling these bikes to a market, but it would be a niche within a niche, but I do believe it exists Smile


I hope so!

Quote:
Guys, like I said, I've only challenged your ideas, based on my experience (which is very likely something you have brushed under the carpet) that does not mean you should assume i know nothing, or what i know is not worth knowing..


Cristian, it is not that you and others know nothing or what you know is not worth knowing. It is simply that the Cleland is an alternative solution to the problem of cycling off-road. And as such it is bound to challenge preconceived notions and so give the impression that other designs are in some way wrong. This is not so. As there are often several equally valid design solutions to any given problem.


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PostPosted: Wed Dec 08, 2010 10:08 am 
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GeoffApps wrote:
This is were I part company with the rest of the world: a bicycle is not inherently stable under any circumstances whatsoever.

Whilst being ridden, at various speeds, certain factors affect its balance, and the ease with which it can be balanced, but it remains inherently unstable.

Any discussion about the stability of a bicycle in motion is, in my book, invalid. There is no stability to discuss. It doesn't exist.



This seems to be about language more than physics.

I ride a bike and I can be impressed or not with its 'stability' at speed, through corners etc maybe I mean balance or poise but I will use the word 'stability.'

I am very much looking forward to seeing these bikes roll off the production line. The Highpath is quite possibly my favourite bike to look at of all time! (and I like the new Cleland too)


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PostPosted: Wed Dec 08, 2010 10:49 am 
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Fair enough GJW :D

I have always thought the US "movement" was later influenced by roadies, which is why, towards the late 80's, & as XC racing got more popular, we were riding bikes with longer top-tubes & stupidly long stems.. well, apart from yourself! :wink:

I had a Zinn, with a super short head tube, & a 150mm stem ! found the photo the other day (ill put it up one day) no bloody wonder i lost control downhill & cracked the frame.

But yes, after all i've said, I do belive there is a market for your for your bike, i guess the challenge would be in targeting it. Maybe outside of the "..cycling domain" look at aiming for people who "use the countryside.." i have some ideas, if you want to pm me ?

Cristian :D


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