Ceramic balls for bearings?

[[email protected]]

Phil Lee writes:

> The Reynolds number of that air at 40mph (and a 3-meter tunnel) is
about > 3.48E6, which is far above the number required for laminar
flow, so the air > stream was indeed turbulent exclusive of the
subject.

That may be in the fluid dynamics sense but the kind of turbulence
that throws people out of their seats in an aircraft is a more chaotic
and troublesome one, often called wind-shear because it has cross
currents. It is this type of turbulence that will throw the bicyclist
from his steed.

Jobst Brandt

 

[[email protected]]

Phil Lee writes:

> The Reynolds number of that air at 40mph (and a 3-meter tunnel) is
about > 3.48E6, which is far above the number required for laminar
flow, so the air > stream was indeed turbulent exclusive of the
subject.

That may be in the fluid dynamics sense but the kind of turbulence
that throws people out of their seats in an aircraft is a more chaotic
and troublesome one, often called wind-shear because it has cross
currents. It is this type of turbulence that will throw the bicyclist
from his steed.

Jobst Brandt

 

[[email protected]]

Phil Lee writes:

> The Reynolds number of that air at 40mph (and a 3-meter tunnel) is
about > 3.48E6, which is far above the number required for laminar
flow, so the air > stream was indeed turbulent exclusive of the
subject.

That may be in the fluid dynamics sense but the kind of turbulence
that throws people out of their seats in an aircraft is a more chaotic
and troublesome one, often called wind-shear because it has cross
currents. It is this type of turbulence that will throw the bicyclist
from his steed.

Jobst Brandt

 

[Marvin]

David L. Johnson wrote:
> On Mon, 31 Oct 2005 10:23:35 -0800, Marvin wrote:
>
> > Yep, it's called a track stand and is a trick I overuse to a tremendous
> > degree at any traffic light, while talking to pedestrians, or indeed
> > when I'm sat on the bike and bored. In the case of a strong headwind,
> > you turn the bars to one side, pedal forward a bit, let the wind push
> > you back a bit, and use those two forces to rock back and forth in the
> > same manner as a tightrope walker. In the absence of a headwind you
> > can use a slight slope to roll you backwards for the same effect.
>
> Are you seriously suggesting that you can track stand in the face of 60mph
> headwinds?

Actually, the question I was answering was just "how can a bicycle
balance when it's motionless?", and I only suggested either a strong
headwind or a slight slope.

Having said that I've spent a while in a city where 30-40mph winds were
commonplace and I used them to pull trackstands, I'd reckon 60mph might
just be doable. It wouldn't be either easy or a whole lot of fun, and
you'd be leant over at a truly comical angle, but if it were constant
and you set up into it right... maybe.

 

[Marvin]

David L. Johnson wrote:
> On Mon, 31 Oct 2005 10:23:35 -0800, Marvin wrote:
>
> > Yep, it's called a track stand and is a trick I overuse to a tremendous
> > degree at any traffic light, while talking to pedestrians, or indeed
> > when I'm sat on the bike and bored. In the case of a strong headwind,
> > you turn the bars to one side, pedal forward a bit, let the wind push
> > you back a bit, and use those two forces to rock back and forth in the
> > same manner as a tightrope walker. In the absence of a headwind you
> > can use a slight slope to roll you backwards for the same effect.
>
> Are you seriously suggesting that you can track stand in the face of 60mph
> headwinds?

Actually, the question I was answering was just "how can a bicycle
balance when it's motionless?", and I only suggested either a strong
headwind or a slight slope.

Having said that I've spent a while in a city where 30-40mph winds were
commonplace and I used them to pull trackstands, I'd reckon 60mph might
just be doable. It wouldn't be either easy or a whole lot of fun, and
you'd be leant over at a truly comical angle, but if it were constant
and you set up into it right... maybe.

 

[Marvin]

David L. Johnson wrote:
> On Mon, 31 Oct 2005 10:23:35 -0800, Marvin wrote:
>
> > Yep, it's called a track stand and is a trick I overuse to a tremendous
> > degree at any traffic light, while talking to pedestrians, or indeed
> > when I'm sat on the bike and bored. In the case of a strong headwind,
> > you turn the bars to one side, pedal forward a bit, let the wind push
> > you back a bit, and use those two forces to rock back and forth in the
> > same manner as a tightrope walker. In the absence of a headwind you
> > can use a slight slope to roll you backwards for the same effect.
>
> Are you seriously suggesting that you can track stand in the face of 60mph
> headwinds?

Actually, the question I was answering was just "how can a bicycle
balance when it's motionless?", and I only suggested either a strong
headwind or a slight slope.

Having said that I've spent a while in a city where 30-40mph winds were
commonplace and I used them to pull trackstands, I'd reckon 60mph might
just be doable. It wouldn't be either easy or a whole lot of fun, and
you'd be leant over at a truly comical angle, but if it were constant
and you set up into it right... maybe.

 

[[email protected]]

Marvin Meredith writes:

> Actually, the question I was answering was just "how can a bicycle
> balance when it's motionless?", and I only suggested either a strong
> headwind or a slight slope.

I hope you have been to a circus where you can see stunt riders with
acrobats on their shoulders balancing on a bicycle that is motionless.
There are various degrees of this skill and many bicyclists have this
skill. However, I don't understand what your headwind or slight slope
has to do with this.

> Having said that I've spent a while in a city where 30-40mph winds
> were commonplace and I used them to pull trackstands, I'd reckon
> 60mph might just be doable. It wouldn't be either easy or a whole
> lot of fun, and you'd be leant over at a truly comical angle, but if
> it were constant and you set up into it right... maybe.

What does wind have to do with track stands other than make them more
difficult?

Jobst Brandt

 

[[email protected]]

Marvin Meredith writes:

> Actually, the question I was answering was just "how can a bicycle
> balance when it's motionless?", and I only suggested either a strong
> headwind or a slight slope.

I hope you have been to a circus where you can see stunt riders with
acrobats on their shoulders balancing on a bicycle that is motionless.
There are various degrees of this skill and many bicyclists have this
skill. However, I don't understand what your headwind or slight slope
has to do with this.

> Having said that I've spent a while in a city where 30-40mph winds
> were commonplace and I used them to pull trackstands, I'd reckon
> 60mph might just be doable. It wouldn't be either easy or a whole
> lot of fun, and you'd be leant over at a truly comical angle, but if
> it were constant and you set up into it right... maybe.

What does wind have to do with track stands other than make them more
difficult?

Jobst Brandt

 

[[email protected]]

Marvin Meredith writes:

> Actually, the question I was answering was just "how can a bicycle
> balance when it's motionless?", and I only suggested either a strong
> headwind or a slight slope.

I hope you have been to a circus where you can see stunt riders with
acrobats on their shoulders balancing on a bicycle that is motionless.
There are various degrees of this skill and many bicyclists have this
skill. However, I don't understand what your headwind or slight slope
has to do with this.

> Having said that I've spent a while in a city where 30-40mph winds
> were commonplace and I used them to pull trackstands, I'd reckon
> 60mph might just be doable. It wouldn't be either easy or a whole
> lot of fun, and you'd be leant over at a truly comical angle, but if
> it were constant and you set up into it right... maybe.

What does wind have to do with track stands other than make them more
difficult?

Jobst Brandt

 

[Marvin]

[email protected] wrote:
> Marvin Meredith writes:
>
> > Actually, the question I was answering was just "how can a bicycle
> > balance when it's motionless?", and I only suggested either a strong
> > headwind or a slight slope.
>
> I hope you have been to a circus where you can see stunt riders with
> acrobats on their shoulders balancing on a bicycle that is motionless.

Normally I'd take Jobst's faintly patronising rhetoric in my stride,
but in this case, actually, yes I have. I go to every circus that
travels within 100 miles and yes, I do watch the stunt riders with
great interest. Never yet have I seen one balancing entirely
motionless, they all rock the bike back and forwards slightly, doing
what I think of as a conventional "track stand". Usually they have
fixed-wheels to accommodate this.

The alternate technique is the one used by trials riders, where even a
slight movement of the wheels is too much. This relies solely on body
English to move the centre of gravity back and forth, is quite a lot
tricker to master and quite often involves legs being stuck out, bodies
being leant over and other things that wouldn't be appreciated by car
drivers. Hence most people use the conventional "trackstand" technique
as briefly summarised by Sheldon -
http://www.sheldonbrown.com/gloss_tp-z.html

> There are various degrees of this skill and many bicyclists have this
> skill. However, I don't understand what your headwind or slight slope
> has to do with this.

Because, at least in the conventional method of turning the bars and
rocking the bike from side to side, some force is needed to push the
bike back after the pedals have pushed it forwards. This force can
come from a fixed-wheel pedalling backwards, from the bike rolling back
down a slope, or, if you're so inclined and the weather is obligingly
windy, a stiff headwind.

> > Having said that I've spent a while in a city where 30-40mph winds
> > were commonplace and I used them to pull trackstands, I'd reckon
> > 60mph might just be doable. It wouldn't be either easy or a whole
> > lot of fun, and you'd be leant over at a truly comical angle, but if
> > it were constant and you set up into it right... maybe.
>
> What does wind have to do with track stands other than make them more
> difficult?

See above.

 

[Marvin]

[email protected] wrote:
> Marvin Meredith writes:
>
> > Actually, the question I was answering was just "how can a bicycle
> > balance when it's motionless?", and I only suggested either a strong
> > headwind or a slight slope.
>
> I hope you have been to a circus where you can see stunt riders with
> acrobats on their shoulders balancing on a bicycle that is motionless.

Normally I'd take Jobst's faintly patronising rhetoric in my stride,
but in this case, actually, yes I have. I go to every circus that
travels within 100 miles and yes, I do watch the stunt riders with
great interest. Never yet have I seen one balancing entirely
motionless, they all rock the bike back and forwards slightly, doing
what I think of as a conventional "track stand". Usually they have
fixed-wheels to accommodate this.

The alternate technique is the one used by trials riders, where even a
slight movement of the wheels is too much. This relies solely on body
English to move the centre of gravity back and forth, is quite a lot
tricker to master and quite often involves legs being stuck out, bodies
being leant over and other things that wouldn't be appreciated by car
drivers. Hence most people use the conventional "trackstand" technique
as briefly summarised by Sheldon -
http://www.sheldonbrown.com/gloss_tp-z.html

> There are various degrees of this skill and many bicyclists have this
> skill. However, I don't understand what your headwind or slight slope
> has to do with this.

Because, at least in the conventional method of turning the bars and
rocking the bike from side to side, some force is needed to push the
bike back after the pedals have pushed it forwards. This force can
come from a fixed-wheel pedalling backwards, from the bike rolling back
down a slope, or, if you're so inclined and the weather is obligingly
windy, a stiff headwind.

> > Having said that I've spent a while in a city where 30-40mph winds
> > were commonplace and I used them to pull trackstands, I'd reckon
> > 60mph might just be doable. It wouldn't be either easy or a whole
> > lot of fun, and you'd be leant over at a truly comical angle, but if
> > it were constant and you set up into it right... maybe.
>
> What does wind have to do with track stands other than make them more
> difficult?

See above.

 

[Marvin]

[email protected] wrote:
> Marvin Meredith writes:
>
> > Actually, the question I was answering was just "how can a bicycle
> > balance when it's motionless?", and I only suggested either a strong
> > headwind or a slight slope.
>
> I hope you have been to a circus where you can see stunt riders with
> acrobats on their shoulders balancing on a bicycle that is motionless.

Normally I'd take Jobst's faintly patronising rhetoric in my stride,
but in this case, actually, yes I have. I go to every circus that
travels within 100 miles and yes, I do watch the stunt riders with
great interest. Never yet have I seen one balancing entirely
motionless, they all rock the bike back and forwards slightly, doing
what I think of as a conventional "track stand". Usually they have
fixed-wheels to accommodate this.

The alternate technique is the one used by trials riders, where even a
slight movement of the wheels is too much. This relies solely on body
English to move the centre of gravity back and forth, is quite a lot
tricker to master and quite often involves legs being stuck out, bodies
being leant over and other things that wouldn't be appreciated by car
drivers. Hence most people use the conventional "trackstand" technique
as briefly summarised by Sheldon -
http://www.sheldonbrown.com/gloss_tp-z.html

> There are various degrees of this skill and many bicyclists have this
> skill. However, I don't understand what your headwind or slight slope
> has to do with this.

Because, at least in the conventional method of turning the bars and
rocking the bike from side to side, some force is needed to push the
bike back after the pedals have pushed it forwards. This force can
come from a fixed-wheel pedalling backwards, from the bike rolling back
down a slope, or, if you're so inclined and the weather is obligingly
windy, a stiff headwind.

> > Having said that I've spent a while in a city where 30-40mph winds
> > were commonplace and I used them to pull trackstands, I'd reckon
> > 60mph might just be doable. It wouldn't be either easy or a whole
> > lot of fun, and you'd be leant over at a truly comical angle, but if
> > it were constant and you set up into it right... maybe.
>
> What does wind have to do with track stands other than make them more
> difficult?

See above.

 

[Jasper Janssen]

On Tue, 01 Nov 2005 19:00:25 GMT, [email protected] wrote:

>I hope you have been to a circus where you can see stunt riders with
>acrobats on their shoulders balancing on a bicycle that is motionless.
>There are various degrees of this skill and many bicyclists have this
>skill. However, I don't understand what your headwind or slight slope
>has to do with this.

Makes it possible to do a trackstand on a freewheeling bike, as he
explains.

Jasper

 

[Jasper Janssen]

On Tue, 01 Nov 2005 19:00:25 GMT, [email protected] wrote:

>I hope you have been to a circus where you can see stunt riders with
>acrobats on their shoulders balancing on a bicycle that is motionless.
>There are various degrees of this skill and many bicyclists have this
>skill. However, I don't understand what your headwind or slight slope
>has to do with this.

Makes it possible to do a trackstand on a freewheeling bike, as he
explains.

Jasper

 

[Jasper Janssen]

On Tue, 01 Nov 2005 19:00:25 GMT, [email protected] wrote:

>I hope you have been to a circus where you can see stunt riders with
>acrobats on their shoulders balancing on a bicycle that is motionless.
>There are various degrees of this skill and many bicyclists have this
>skill. However, I don't understand what your headwind or slight slope
>has to do with this.

Makes it possible to do a trackstand on a freewheeling bike, as he
explains.

Jasper

 

[Donald Gillies]

Werehatrack <[email protected]> writes:

>On Fri, 28 Oct 2005 18:10:26 GMT, Jasper Janssen <[email protected]>
>wrote:

>>In another bike group someone appears to want to buy ceramic bearing
>>balls. WTF? Why on earth?

>Boutique mentality. It's exotic and different....

imho, ceramic ball bearings will NEVER sell. However, if you put them
in a cheap $5 taiwanese hub and etch "CERAMIC BEARINGS" all over the
hub, in bright visible colors, then i'm sure you can sell these
puppies for $100/pop if they work at all ...

- Cynically yours,
San Diego, CA

 

[Donald Gillies]

Werehatrack <[email protected]> writes:

>On Fri, 28 Oct 2005 18:10:26 GMT, Jasper Janssen <[email protected]>
>wrote:

>>In another bike group someone appears to want to buy ceramic bearing
>>balls. WTF? Why on earth?

>Boutique mentality. It's exotic and different....

imho, ceramic ball bearings will NEVER sell. However, if you put them
in a cheap $5 taiwanese hub and etch "CERAMIC BEARINGS" all over the
hub, in bright visible colors, then i'm sure you can sell these
puppies for $100/pop if they work at all ...

- Cynically yours,
San Diego, CA

 

[Phil, Squid-in-Training]

Donald Gillies wrote:
> Werehatrack <[email protected]> writes:
>
>> On Fri, 28 Oct 2005 18:10:26 GMT, Jasper Janssen
>> <[email protected]> wrote:
>
>>> In another bike group someone appears to want to buy ceramic bearing
>>> balls. WTF? Why on earth?
>
>> Boutique mentality. It's exotic and different....
>
> imho, ceramic ball bearings will NEVER sell. However, if you put them
> in a cheap $5 taiwanese hub and etch "CERAMIC BEARINGS" all over the
> hub, in bright visible colors, then i'm sure you can sell these
> puppies for $100/pop if they work at all ...

Skip the "if you put them in" part of your comment, and it'll be
economically feasible, too!
--
Phil, Squid-in-Training

 

[Phil, Squid-in-Training]

Donald Gillies wrote:
> Werehatrack <[email protected]> writes:
>
>> On Fri, 28 Oct 2005 18:10:26 GMT, Jasper Janssen
>> <[email protected]> wrote:
>
>>> In another bike group someone appears to want to buy ceramic bearing
>>> balls. WTF? Why on earth?
>
>> Boutique mentality. It's exotic and different....
>
> imho, ceramic ball bearings will NEVER sell. However, if you put them
> in a cheap $5 taiwanese hub and etch "CERAMIC BEARINGS" all over the
> hub, in bright visible colors, then i'm sure you can sell these
> puppies for $100/pop if they work at all ...

Skip the "if you put them in" part of your comment, and it'll be
economically feasible, too!
--
Phil, Squid-in-Training

 

[[email protected]]

i agree
scoter could commit