Left hand threads.

[zog]

Moike wrote:
> zog wrote:


>>>
>>
>> well I look it this way, if for any reason the pedal bearing becomes
>> sticky, the only direction the threads can move is tighter, if there
>> was a righthand thread on the left pedal it would unscrew
> No, that's precisely wrong.
>
> If the thread is loose, riding forward would tend to loosen a left hand
> thread on a left hand pedal. Go and have a look at your bike. Loosen a
> pedal, turn it and see what happens.
>
> To see precession, try this.
>

yeah your are right actually, I'll go back to the precession idea

 

[adam85]

"Moike" <[email protected]> wrote in message
news:[email protected]...

> If the thread is loose, riding forward would tend to loosen a left hand
> thread on a left hand pedal. Go and have a look at your bike. Loosen a
> pedal, turn it and see what happens.
>
> To see precession, try this.
>
> Take a pencil. Hold it loosely in your left hand. With your right hand,
> hold the end of the pen lightly and 'stir' it in a clockwise direction.
> You will see the pen turn anti-clockwise as it rolls around.
>
> Much the same thing can happen with a pedal, not because the rotation of
> the pedal with respect to the crank tends to undo the thread, (which it
> doesn't) but because the direction of application of force moves around
> the pedal shaft, causing it to tend to 'roll' like the pencil in your
> hand.
>
> That's the thing. The usual explanation for the left hand thread is what
> you said, but it isn't so.
>
> Moike

Thanks Moike - good description.

Adam

 

[dave]

[email protected] wrote:
> Michael Warner <[email protected]> wrote:
>> On 20 Nov 2006 22:13:16 +0200, Moike wrote:
>>
>>> Given the confusion they cause, is there any rational reason for
>> having a left
>>> hand thread on left side pedals?
>> http://en.wikipedia.org/wiki/Bicycle_pedal
>>
>> See second paragraph.
>>
>> --
>> Home page: http://members.westnet.com.au/mvw
>
> Fascinating. Thank you. It's been worrying me for a while.
>
> Moike

When and if we do find an alien spacecraft its my belief it will be
built of materials we understand and in the main put together in ways we
understand. Just like in the main the ancient egyptians would look at a
modern house and quickly figure out most of it.

The real question is will they use left hand threads with the occasional
right hand thread for bolts and screws or do it they way we do. And
that will probably depend on if they are mostly left handed (or
tentincled ) or not

Dave

 

[dave]

Duracell Bunny wrote:
> Moike wrote:
>> Given the confusion they cause, is there any rational reason for
>> having a left
>> hand thread on left side pedals?
>>
>> Was it simply a mistake made long ago and carried on for the sake of
>> consistency?
>>
>> Moike
>
> I believe cars with wire wheels also have left handed threads on the
> left side, for the same reasons stated. I've had cars suffer loosened
> wheel nuts, always on the left side of the vehicle. Some of the less
> charitable on this NG will confirm I have a screw loose too
>

I promise you this is in fact the case

Wire wheels I mean

Dave

 

[BT Humble]

dave wrote:
> When and if we do find an alien spacecraft its my belief it will be
> built of materials we understand and in the main put together in ways we
> understand. Just like in the main the ancient egyptians would look at a
> modern house and quickly figure out most of it.

And those ancient Egyptians would shake their heads and cluck their
tongues at our shoddy standards of construction! ;-)


BTH

 

[Donga]

dave wrote:
> [email protected] wrote:
> > Michael Warner <[email protected]> wrote:
> >> On 20 Nov 2006 22:13:16 +0200, Moike wrote:
> >>
> >>> Given the confusion they cause, is there any rational reason for
> >> having a left
> >>> hand thread on left side pedals?
> >> http://en.wikipedia.org/wiki/Bicycle_pedal
> >>
> >> See second paragraph.
> >>
> >> --
> >> Home page: http://members.westnet.com.au/mvw
> >
> > Fascinating. Thank you. It's been worrying me for a while.
> >
> > Moike
>
> When and if we do find an alien spacecraft its my belief it will be
> built of materials we understand and in the main put together in ways we
> understand. Just like in the main the ancient egyptians would look at a
> modern house and quickly figure out most of it.
>
> The real question is will they use left hand threads with the occasional
> right hand thread for bolts and screws or do it they way we do. And
> that will probably depend on if they are mostly left handed (or
> tentincled ) or not
>
> Dave

Clearly you have no idea about alien or ancient egyptian technology.
Haven't you been watching Stargate SG-1? Sheesh.

Donga