Left hand threads.

Michael Warner said:

Moike said:

Given the confusion they cause, is there any rational reason for

having a left

Quoted message said:

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

Zebee Johnstone said:

In aus.bicycle on 20 Nov 2006 22:13:16 +0200

Moike said:

Given the confusion they cause, is there any rational reason for

having a left

Quoted message said:

hand thread on left side pedals?

I suppose it depends on how long you want the pedal to stay on the
bike.

IF you are happy to unscrew it with each pedal stroke....

Zebee

That sort of simplistic explanation is what leads to the confusion, I guess,
since it suggests the LH thread is there to counter the unscrewing effect of
pedal rotation in the crank. The rotation of the pedal would have the opposite
effect were it not for the less obvious 'precession' effect outlined above.

Moike

Moike said:

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

In aus.bicycle on 20 Nov 2006 22:13:16 +0200

Moike said:

Given the confusion they cause, is there any rational reason for having a left
hand thread on left side pedals?

I suppose it depends on how long you want the pedal to stay on the
bike.

IF you are happy to unscrew it with each pedal stroke....

Zebee

Moike said:

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 🙂

--
Karen

"Reverse the polarity and invert the particle flux!"
"You mean put the batteries in the other way?"
"...yes."
-Star Trek (any of them)

In aus.bicycle on 20 Nov 2006 22:50:49 +0200

Quoted message said:

That sort of simplistic explanation is what leads to the confusion, I guess,
since it suggests the LH thread is there to counter the unscrewing effect of
pedal rotation in the crank. The rotation of the pedal would have the opposite
effect were it not for the less obvious 'precession' effect outlined above.

I agree in that I at first thought is was unscrewing because of that,
realised that it's not likely, then realised that modern manufacturing
would likely want to have standardisation, so it still had to be
unscrewing even if it wasn't the immediately obvious method.

Zebee

Duracell Bunny said:

Moike said:

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 🙂

Almost all trucks (and some larger vans) have left-hand-threaded wheel
studs on the left of the vehicle.

It's a fiendish trap for young players (the first time I needed to
change a wheel on the left side I thought my truck was too small to
warrant it, and broke a stud).

BTH

Quoted message said:

Michael Warner said:

Moike said:

Given the confusion they cause, is there any rational reason for

having a left

Quoted message said:

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

Do you believe me now? ;-)

BTH

Quoted message said:

Michael Warner said:

Moike said:

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.

Quoted message said:

Fascinating. Thank you. It's been worrying me for a while.

I don't know if they still do, but Yankee cars had left hand wheel nuts on
one side of the car and right hand thread on the other. No good reason
really. With knock-offs, as in older British sports cars, it was imperative.

Theo

BT Humble said:

It's a fiendish trap for young players

And old ones. {:-(
<standing on tyre lever in Griffth park going wtf!
swmbo usually has the flats and calls a nice man from NRMA, which we
ended up doing. Yer, she hit the pothole this time too>

Duracell Bunny said:

Moike said:

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 🙂

--
Karen

Oh no, absolutely not, she's the full quid! She's got back on the bike
after years off, when others have swelled numerous sizes. How sane is
that? Different, maybe, but sane.

Donga

Moike said:

Given the confusion they cause, is there any rational reason for having a left
hand thread on left side pedals?

Moike

Talking about left hand threads and how frustrating they can be, have a look here but it's a bit rude for the girls though.

anvari.org845.htmlOpen ↗

Theo Bekkers said:

I don't know if they still do, but Yankee cars had left hand wheel nuts on
one side of the car and right hand thread on the other. No good reason
really. With knock-offs, as in older British sports cars, it was imperative.

some do some don't, my 28ford is all righthand thread on the wheel nuts,
I think some 20-30s Buicks and Dodges had lefthand wheel nuts on the
left side.

and as you said with left side knockoffs it is for the same reason as
lefthand bike pedals.

quote='zog'Theo Bekkers said:

I don't know if they still do, but Yankee cars had left hand wheel nuts on
one side of the car and right hand thread on the other. No good reason
really. With knock-offs, as in older British sports cars, it was imperative.

some do some don't, my 28ford is all righthand thread on the wheel nuts,
I think some 20-30s Buicks and Dodges had lefthand wheel nuts on the
left side.

and as you said with left side knockoffs it is for the same reason as
lefthand bike pedals.[/QUOTE]

Old Valiants had left hand wheel nuts. Well the VE did anyway. Never understood why they had a VC & VE model valiants and commodes, but not a VD. I thought it'd be quite a catchy name.

I still don't understand that wiki description of precession though.

"The left-hand pedal has a left-hand thread, to prevent it becoming loose from an effect called precession. Although the pedal turns clockwise in its bearing relative to the crankarm, the force from the rider's foot presses the bearing against the crankarm thread at a point which rolls around clockwise, thus slowly pulling the outside of the bearing anticlockwise because of friction."

I get all but the last bit - how does the force pull the outside of the bearing anticlockwise?

adam85 said:

zog said:

Theo Bekkers said:

I don't know if they still do, but Yankee cars had left hand wheel

nuts on

Quoted message said:

one side of the car and right hand thread on the other. No good

reason

Quoted message said:

really. With knock-offs, as in older British sports cars, it was

imperative.

some do some don't, my 28ford is all righthand thread on the wheel
nuts,
I think some 20-30s Buicks and Dodges had lefthand wheel nuts on the
left side.

and as you said with left side knockoffs it is for the same reason as
lefthand bike pedals.

Old Valiants had left hand wheel nuts. Well the VE did anyway. Never
understood why they had a VC & VE model valiants and commodes, but not
a VD. I thought it'd be quite a catchy name.

🙂 the marketing guys probably thought it would a negative for the
sales of the car, bad enough when people call them commodes 😉

Quoted message said:

I still don't understand that wiki description of precession though.

"The left-hand pedal has a left-hand thread, to prevent it becoming
loose from an effect called precession. Although the pedal turns
clockwise in its bearing relative to the crankarm, the force from the
rider's foot presses the bearing against the crankarm thread at a point
which rolls around clockwise, thus slowly pulling the outside of the
bearing anticlockwise because of friction."

I get all but the last bit - how does the force pull the outside of the
bearing anticlockwise?

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

zog said:

Theo Bekkers said:

I don't know if they still do, but Yankee cars had left hand wheel
nuts on one side of the car and right hand thread on the other. No
good reason really. With knock-offs, as in older British sports
cars, it was imperative.

some do some don't, my 28ford is all righthand thread on the wheel
nuts, I think some 20-30s Buicks and Dodges had lefthand wheel nuts
on the left side.

The '61 Buick I owned in the US had them.

Theo

adam85 said:

Never
understood why they had a VC & VE model valiants and commodes, but not
a VD. I thought it'd be quite a catchy name.

I believe the Holden HSV people threatened to sue if they used another
VD name.

zog said:

adam85 said:

zog said:

Theo Bekkers wrote:

> I don't know if they still do, but Yankee cars had left hand wheel
nuts on
> one side of the car and right hand thread on the other. No good
reason
> really. With knock-offs, as in older British sports cars, it was
imperative.

some do some don't, my 28ford is all righthand thread on the wheel
nuts,
I think some 20-30s Buicks and Dodges had lefthand wheel nuts on the
left side.

and as you said with left side knockoffs it is for the same reason as
lefthand bike pedals.

Old Valiants had left hand wheel nuts. Well the VE did anyway. Never
understood why they had a VC & VE model valiants and commodes, but not
a VD. I thought it'd be quite a catchy name.

🙂 the marketing guys probably thought it would a negative for the
sales of the car, bad enough when people call them commodes 😉

Quoted message said:

I still don't understand that wiki description of precession though.
"The left-hand pedal has a left-hand thread, to prevent it becoming
loose from an effect called precession. Although the pedal turns
clockwise in its bearing relative to the crankarm, the force from the
rider's foot presses the bearing against the crankarm thread at a point
which rolls around clockwise, thus slowly pulling the outside of the
bearing anticlockwise because of friction."

I get all but the last bit - how does the force pull the outside of the
bearing anticlockwise?

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.

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

Mike said:

adam85 said:

Never
understood why they had a VC & VE model valiants and commodes, but not
a VD. I thought it'd be quite a catchy name.

I believe the Holden HSV people threatened to sue if they used another
VD name.

I had a VF Valiant a few years ago. It had the LH threads, I think the
VG still did too but the VH went to RH. If you read rec.bicycles.tech
there's been a bit of discussion on this subject over the years.

Bruce.