Eeek! No Spokes!

Tosspot wrote on 16/09/2006 08:33 +0100:

Quoted message said:

Following on from the Handbag Bike.

http://www.kancept.com/kancepts/show/nulla_bike--190

"Simply a bicyle with no central hub systems, that however, will work.
This bike was designed so that people could display rather than store it."

No mention of riding it then? ;-)

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

"Tony Raven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Tosspot wrote on 16/09/2006 08:33 +0100:

Quoted message said:

Following on from the Handbag Bike.

http://www.kancept.com/kancepts/show/nulla_bike--190

"Simply a bicyle with no central hub systems, that however, will work.
This bike was designed so that people could display rather than store it."

No mention of riding it then? ;-)

It's a matter of interpretation. I read it the same as you the first time.
I think what is meant is: rather than hide it in a shed it's good enough to
be displayed in the living room.

No good to me though, cant imagine the wheels coping with the stresses that
i'd impose on them ;-(

in message <[email hidden]>, Tony Raven

(') said:

Tosspot wrote on 16/09/2006 08:33 +0100:

Quoted message said:

Following on from the Handbag Bike.

http://www.kancept.com/kancepts/show/nulla_bike--190

"Simply a bicyle with no central hub systems, that however, will work.
This bike was designed so that people could display rather than store
it."

No mention of riding it then? ;-)

Hubless wheels are perfectly feasible and can work. Getting one to work
efficiently without an enormous weight penalty might be difficult and
expensive, but should not be impossible.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

[ This .sig intentionally left blank ]

Simon Brooke said:

Hubless wheels are perfectly feasible and can work. Getting one to work
efficiently without an enormous weight penalty might be difficult and
expensive, but should not be impossible.

Although getting one to work with a rim that slender is going to need
something a bit stronger than monlithic extruded diamond, I think.

regards, Ian SMith
--
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|o o|
|/ \|

Ian Smith wrote on 16/09/2006 10:25 +0100:

Quoted message said:

Simon Brooke said:

Hubless wheels are perfectly feasible and can work. Getting one to work
efficiently without an enormous weight penalty might be difficult and
expensive, but should not be impossible.

Although getting one to work with a rim that slender is going to need
something a bit stronger than monlithic extruded diamond, I think.

regards, Ian SMith

As Simon says, its been done before by Osmos who have built motorcycles
and cars with them. http://www.osmoswheel.com/

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

in message <[email hidden]>, Tony Raven

(') said:

Tosspot wrote on 16/09/2006 08:33 +0100:

Quoted message said:

Following on from the Handbag Bike.

http://www.kancept.com/kancepts/show/nulla_bike--190

"Simply a bicyle with no central hub systems, that however, will work.
This bike was designed so that people could display rather than store
it."

No mention of riding it then? ;-)

Hubless wheels are perfectly feasible and can work. Getting one to work
efficiently without an enormous weight penalty might be difficult and
expensive, but should not be impossible.

I've see the hubless drive concept in operation before. It would have been
in Cycling Weekly, many years back. Obviously the concept has not taken off.
The drive to the rear wheel would have to be a mechanical or friction
contact.
I can't see how such a drive train would be anywhere near as efficient as
the
humble chain.

--
Dave Lloyd
So open minded, my brains dribbled out.

Tony Raven said:

Ian Smith wrote on 16/09/2006 10:25 +0100:

Quoted message said:

Simon Brooke said:

Hubless wheels are perfectly feasible and can work. Getting one to work
efficiently without an enormous weight penalty might be difficult and
expensive, but should not be impossible.

Although getting one to work with a rim that slender is going to need
something a bit stronger than monlithic extruded diamond, I think.

As Simon says, its been done before by Osmos who have built motorcycles
and cars with them. http://www.osmoswheel.com/

I didn't say it couldn't be done, I said I don't think it can be done
WITH A RIM THAT SLENDER. In the pictures, it's got a rim that's
apparently rather thinner than a spoked bike wheel has.

regards, Ian SMith
--
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|o o|
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david lloyd said:

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...

<snip>

Quoted message said:

Quoted message said:

Hubless wheels are perfectly feasible and can work. Getting one to
work efficiently without an enormous weight penalty might be
difficult and expensive, but should not be impossible.

I've see the hubless drive concept in operation before. It would have
been in Cycling Weekly, many years back. Obviously the concept has
not taken off. The drive to the rear wheel would have to be a
mechanical or friction contact. I can't see how such a drive train
would be anywhere near as efficient as the humble chain.

Yeah, but you'd lose all those wizzy 'round spoke thingies. Just think
what they cost you at 30mph.

"Tosspot" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

david lloyd said:

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...

<snip>

Quoted message said:

Quoted message said:

Hubless wheels are perfectly feasible and can work. Getting one to
work efficiently without an enormous weight penalty might be
difficult and expensive, but should not be impossible.

I've see the hubless drive concept in operation before. It would have
been in Cycling Weekly, many years back. Obviously the concept has
not taken off. The drive to the rear wheel would have to be a
mechanical or friction contact. I can't see how such a drive train
would be anywhere near as efficient as the humble chain.

Yeah, but you'd lose all those wizzy 'round spoke thingies. Just think
what they cost you at 30mph.

Been toying with the idea of putting Spokey dokies on my Roadie

in message <[email hidden]>, Ian Smith

(') said:

On Sat, 16 Sep 2006 12:14:54 +0100, Tony Raven <[email hidden]>

Quoted message said:

Ian Smith wrote on 16/09/2006 10:25 +0100:

Quoted message said:

On Sat, 16 Sep 2006 09:20:37 +0100, Simon Brooke
<[email hidden]> wrote:
> Hubless wheels are perfectly feasible and can work. Getting one to
> work efficiently without an enormous weight penalty might be
> difficult and expensive, but should not be impossible.

Although getting one to work with a rim that slender is going to need
something a bit stronger than monlithic extruded diamond, I think.

As Simon says, its been done before by Osmos who have built motorcycles
and cars with them. http://www.osmoswheel.com/

I didn't say it couldn't be done, I said I don't think it can be done
WITH A RIM THAT SLENDER. In the pictures, it's got a rim that's
apparently rather thinner than a spoked bike wheel has.

Osmos include, on their website, an image of a pedal cycle with rims
equally slender. However

(i) the only design on the Osmos website which is photographed as opposed
to being presented as a CAD rendering appears to be this motorbike
http://www.osmoswheel.com/images/galerie/intersection_076.jpg
and in none of the photographs does it appear to be moving

(ii) like you I am highly sceptical that a rim that slender could
practicably be made stiff and strong enough to support a cyclist.

Like I say, such wheels are possible, but that doesn't necessarily mean
they're viable.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; All in all you're just another hick in the mall
-- Drink C'lloid

Simon Brooke wrote on 18/09/2006 15:23 +0100:

Quoted message said:

(ii) like you I am highly sceptical that a rim that slender could
practicably be made stiff and strong enough to support a cyclist.

Like I say, such wheels are possible, but that doesn't necessarily mean
they're viable.

As long as the bearing through which the rim passes is at the ground
contact point the rim is acting more like a tank track to transfer the
weight from the bearing through the rim direct to the ground. The rest
of the rim will be unloaded so its properties are irrelevant as long as
it is strong enough not to flop over.

OTOH if the bearing is a long way from the ground contact point, I can
agree that getting a strong enough rim then would be tough.

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

Tony Raven said:

Simon Brooke wrote on 18/09/2006 15:23 +0100:

Quoted message said:

(ii) like you I am highly sceptical that a rim that slender could
practicably be made stiff and strong enough to support a cyclist.

Like I say, such wheels are possible, but that doesn't necessarily mean
they're viable.

OTOH if the bearing is a long way from the ground contact point, I can
agree that getting a strong enough rim then would be tough.

On the concept in question, they are 170ish degrees (front) and 90
degrees (rear) round the wheel from the contact point. The rims are
very, very slender. I don't think it's practical with current
materials technology, though might be theoretically viable if you grow
your rim as a single seamless crystal of something very stiff (hence
my reference to diamond).

regards, Ian SMith
--
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|o o|
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In article said:

Simon Brooke wrote on 18/09/2006 15:23 +0100:

Quoted message said:

(ii) like you I am highly sceptical that a rim that slender could
practicably be made stiff and strong enough to support a cyclist.

[...]

Quoted message said:

As long as the bearing through which the rim passes is at the ground
contact point [...]
OTOH if the bearing is a long way from the ground contact point, I can
agree that getting a strong enough rim then would be tough.

And, going back to the original link
http://www.kancept.com/kancepts/show/nulla_bike--190
the front wheel bearing is about as far from the ground as it can be.

Similarly with http://www.osmoswheel.com/images/galerie/galerie13.jpg
which appears on a page labelled "Photo gallery" and has a stand which
one might expect to be omitted from a rendering, but looks completely
impractical to me - but it does take advantage of the concept to use
geometry that would be impossible with a conventional wheel, with the
bottom bracket inside the wheel. Whether there is any actual point to
allowing that, I'm not sure....

Tony Raven said:

As long as the bearing through which the rim passes is at the ground
contact point the rim is acting more like a tank track to transfer the
weight from the bearing through the rim direct to the ground. The rest
of the rim will be unloaded so its properties are irrelevant as long as
it is strong enough not to flop over.

Until you try to turn a corner...
TL

The Luggage said:

Tony Raven said:

As long as the bearing through which the rim passes is at the ground
contact point the rim is acting more like a tank track to transfer the
weight from the bearing through the rim direct to the ground. The rest
of the rim will be unloaded so its properties are irrelevant as long as
it is strong enough not to flop over.

Until you try to turn a corner...

I wondered that, but then I thought why should it make any difference?

Would this thing not be unstable? Depends entirely on the rotating mass
of course which, in this case, is just the rim.

[Queue thought process] ... depends on the distance of the mass from
the axis of rotation - do hubs and spokes contribute much to the
rotational momentum? There's maths out there somewhere...

In article <[email hidden]>

Simon L said:

Would this thing not be unstable? Depends entirely on the rotating mass
of course which, in this case, is just the rim.

[Queue thought process] ... depends on the distance of the mass from
the axis of rotation - do hubs and spokes contribute much to the
rotational momentum? There's maths out there somewhere...

I don't think gyroscopic effect has much to do with it - it's more
about steering geometry and weight distribution.

Ian Smith said:

I don't think it's practical with current
materials technology, though might be theoretically viable if you grow
your rim as a single seamless crystal of something very stiff (hence
my reference to diamond).

Or alternatively, stiffen and strengthen the rim with something like,
um, spokes!

Oh, hang on a mo...

PhilD

--
<><

Quoted message said:

I don't think gyroscopic effect has much to do with it - it's more
about steering geometry and weight distribution.

Shirley rotational momentum in a plane - the gyroscopic effect - is all
there is to it. My bike is hideously unstable when it's not moving.

Long ago when I was an undergraduate we did an experiment with a
bicycle wheel with handles on the axle ( and a rotating desk chair but
I can't recall the details).

With a 26" wheel rotating at around 60 rpm (a rolling speed of about
5mph) it takes a heck of a lot of brute force to change the plane the
wheel revolves in.