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 🙂
"Moike" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
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.
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 🙂
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 🙂
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! ;-)
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.
