<VV> Subject: Re: Fuel Leak - Now Lug Nuts, etc.
Mike McGowan
mcvair at sbcglobal.net
Fri Sep 28 12:24:50 EDT 2018
Comments about left-hand threaded knockoff hubs on the right side are missing the big obvious reason: they are knock-offs with ears. If you hit a curb or road debris while driving forward you would remove them instantly if they were threaded the other way.
--Mike McGowan
On Friday, September 28, 2018 11:00 AM, "virtualvairs-request at corvair.org" <virtualvairs-request at corvair.org> wrote:
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Today's Topics:
1. Re: Fuel Leak - Now Lug Nuts, etc. (roboman91324 at aol.com)
2. Re: Fuel Leak - Now Lug Nuts, etc. (Hugo Miller)
3. Re: Was Fuel Leak Now Head Nuts (Bryan Blackwell)
----------------------------------------------------------------------
Message: 1
Date: Fri, 28 Sep 2018 07:41:43 -0400
From: roboman91324 at aol.com
To: Hugo at aruncoaches.co.uk, virtualvairs at corvair.org
Subject: Re: <VV> Fuel Leak - Now Lug Nuts, etc.
Message-ID: <1661ffc0b86-1ec2-b45 at webjas-vac203.srv.aolmail.net>
Content-Type: text/plain; charset=utf-8
Hugo,
?
Both the coriolis effect and gyroscopic precession are miniscule and probably irrelevant in the situation we are discussing.? The fretting effect (mechanical precession) is the major issue.
?
What I believe is happening is there is cyclic compression and decompression of whatever material the wheel is made of as it turns.? The weight of the car is transferred to the wheel at the hub.? The weight is then transmitted across the radius of the wheel to the tire and eventually to the ground.? As the wheel rolls, the compression forces rotate as well.? On the left side wheel while rolling forward in a counterclockwise direction the force profile will compress material at the lug nut in a counterclockwise direction in waves?repeatedly?effecting each lug in turn.? This will tend to coax the nut in a counterclockwise direction if not held in place with friction.? Therefore, a left hand thread will resist this effect.??I would expect this issue to be more pronounced with a smaller lug bolt circle.??After working this out in my alleged mind, this may not be mechanical precession in the strictest sense.? Mechanical precession results from two circular surfaces of different diameters
rotating together.??
?
The introduction of left hand threads "back when" could have resulted from mere observation and experimentation.? Loose lug nuts almost always occurred on the left side but rarely on the right.? The difference was the direction of wheel rotation left side to right.? They experimented with left hand threads on the left wheels and the problem went away.??
?
Your question regarding knock-offs with left hand threads on the right side wheels is a different issue.? This appears to be due to true mechanical precession.? If slightly loose, the hub's contact surface is smaller diameter than the knock-off nut/cap.? On the right wheel, this will tend to work the nut/cap in a counterclockwise direction.? in this case, you will want a left hand thread on the right wheels.? I imagine it might be a bad idea to tow a vehicle with knock-offs from its rear with the front wheels on the ground.
?
Doc
?
In a message dated 9/28/2018 2:04:03 AM Pacific Standard Time, Hugo at aruncoaches.co.uk writes:
?
?
Funny you should say that, as I was about to agree with you that it might indeed be the Coriolis effect at work. In truth I?m not sure what forces are at work that make wheel nuts do what they do, or more specifically why you are better off with a left-hand thread on wheels that rotate anti-clockwise. I?m even more surprised that somebody figured this out so early on in the days of motoring, since the whole concept of lug nuts didn?t exist before the motor car.
Now tell me why RIGHT-HAND knock-off wheels have a LEFT-HAND thread on the spinners Winking smile?
?
?
From:roboman91324 at aol.com
Sent: Friday, September 28, 2018 4:20 AM
To:Hugo at aruncoaches.co.uk ; virtualvairs at corvair.org
Subject: Re: <VV> Fuel Leak
?
Hugo,
?
Please excuse my last post.? Mechanical precession is exactly what is going on with left-side lug nut loosening.? I assumed you were talking about precession as it pertains to the dynamics of rotating mass.? I. E. gyroscopic precession.? I have always known it as epicyclic fretting.
?
By the way, mechanical precession is still a concern but the deeper tapered lug nuts added just enough friction to compensate.? In addition, the taper (acorn) itself, not just the added contact area, has been the solution to the issue in two ways.? First, the taper acts as a wedge which increases the applied force "N" in the frictional force equation.? Second, the taper allows for different diameters at different points of contact.? These interesting tricks of Physics were a game changer.
?
Again, my apologies,
?
Doc
?
PS:? I believe the rest of my posts to be accurate but you never know.
------------------------------
Message: 2
Date: Fri, 28 Sep 2018 14:31:29 +0100
From: "Hugo Miller" <Hugo at aruncoaches.co.uk>
To: <roboman91324 at aol.com>, <virtualvairs at corvair.org>
Subject: Re: <VV> Fuel Leak - Now Lug Nuts, etc.
Message-ID: <2D2E2B86B5B347218626E495300AD131 at HugoHP>
Content-Type: text/plain; charset="utf-8"
Yes, this all makes perfect sense. Especially the precession effect on knock-offs. I should have spotted that for myself ? thank you!
From: roboman91324 at aol.com
Sent: Friday, September 28, 2018 12:41 PM
To: Hugo at aruncoaches.co.uk ; virtualvairs at corvair.org
Subject: Re: <VV> Fuel Leak - Now Lug Nuts, etc.
Hugo,
Both the coriolis effect and gyroscopic precession are miniscule and probably irrelevant in the situation we are discussing. The fretting effect (mechanical precession) is the major issue.
What I believe is happening is there is cyclic compression and decompression of whatever material the wheel is made of as it turns. The weight of the car is transferred to the wheel at the hub. The weight is then transmitted across the radius of the wheel to the tire and eventually to the ground. As the wheel rolls, the compression forces rotate as well. On the left side wheel while rolling forward in a counterclockwise direction the force profile will compress material at the lug nut in a counterclockwise direction in waves repeatedly effecting each lug in turn. This will tend to coax the nut in a counterclockwise direction if not held in place with friction. Therefore, a left hand thread will resist this effect. I would expect this issue to be more pronounced with a smaller lug bolt circle. After working this out in my alleged mind, this may not be mechanical precession in the strictest sense. Mechanical precession results from two circular surfaces of different diameters
rotating together.
The introduction of left hand threads "back when" could have resulted from mere observation and experimentation. Loose lug nuts almost always occurred on the left side but rarely on the right. The difference was the direction of wheel rotation left side to right. They experimented with left hand threads on the left wheels and the problem went away.
Your question regarding knock-offs with left hand threads on the right side wheels is a different issue. This appears to be due to true mechanical precession. If slightly loose, the hub's contact surface is smaller diameter than the knock-off nut/cap. On the right wheel, this will tend to work the nut/cap in a counterclockwise direction. in this case, you will want a left hand thread on the right wheels. I imagine it might be a bad idea to tow a vehicle with knock-offs from its rear with the front wheels on the ground.
Doc
In a message dated 9/28/2018 2:04:03 AM Pacific Standard Time, Hugo at aruncoaches.co.uk writes:
Funny you should say that, as I was about to agree with you that it might indeed be the Coriolis effect at work. In truth I?m not sure what forces are at work that make wheel nuts do what they do, or more specifically why you are better off with a left-hand thread on wheels that rotate anti-clockwise. I?m even more surprised that somebody figured this out so early on in the days of motoring, since the whole concept of lug nuts didn?t exist before the motor car.
Now tell me why RIGHT-HAND knock-off wheels have a LEFT-HAND thread on the spinners
From: roboman91324 at aol.com
Sent: Friday, September 28, 2018 4:20 AM
To: Hugo at aruncoaches.co.uk ; virtualvairs at corvair.org
Subject: Re: <VV> Fuel Leak
Hugo,
Please excuse my last post. Mechanical precession is exactly what is going on with left-side lug nut loosening. I assumed you were talking about precession as it pertains to the dynamics of rotating mass. I. E. gyroscopic precession. I have always known it as epicyclic fretting.
By the way, mechanical precession is still a concern but the deeper tapered lug nuts added just enough friction to compensate. In addition, the taper (acorn) itself, not just the added contact area, has been the solution to the issue in two ways. First, the taper acts as a wedge which increases the applied force "N" in the frictional force equation. Second, the taper allows for different diameters at different points of contact. These interesting tricks of Physics were a game changer.
Again, my apologies,
Doc
PS: I believe the rest of my posts to be accurate but you never know.
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Message: 3
Date: Fri, 28 Sep 2018 10:18:14 -0400
From: Bryan Blackwell <bryan at skiblack.com>
To: Frank Duval <corvairduval at cox.net>
Cc: Virtual Vairs <virtualvairs at corvair.org>
Subject: Re: <VV> Was Fuel Leak Now Head Nuts
Message-ID: <AE2FD33E-D856-4928-BD52-4500BA745E11 at skiblack.com>
Content-Type: text/plain; charset=us-ascii
I'll second Frank. I use Anti Seize (or Loctite in a few spots) on just about all threaded fasteners. A properly torqued - note use of the word 'torqued' - fastener won't come loose. Don't just slop Anti Seize everywhere, just on the threads please. Since torque values on a Corvair are generally a range, I use the lower values.
--Bryan
> On Sep 28, 2018, at 12:14 AM, FrankDuVal via VirtualVairs <virtualvairs at corvair.org> wrote:
>
> I live in the rusty easy and have been using Anti-Seize on Corvair head nuts for over 35 years. I DO check the studs before installing heads by using pipe spacers and torque the nuts to 35 ft-lbs. If they pass this test, then I put the head on, Anti-Seize the threads and torque to 30-33 ft-lbs depending on year.
>
>
> And despite the west coasters on many forums saying I will loose my wheels, I also use grease/oil/Anti-Seize (whatever is close by) on lug nuts!
>
>
> Worked for me on thousands of cars.
------------------------------
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