<VV> LH lug nuts

[Joel McGregor]

There is an answer to the wheels falling off and it isn't LH threads.  When the US changed to hub center wheels on trucks that isn't the only thing that changed.  The previous lug center system uses a fastener for each wheel so you only have 4 & 2 surfaces (drum + wheel, wheel) being clamped together.  When they changed to hub center they went to a single nut holding both wheels on which made it have to clamp 6 (drum + wheel + wheel) surfaces.  Any paint, dirt, rust, etc between the surfaces quickly becomes too much compressible junk for the bolt stretch at proper torque to overcome.  With the old hub center system the inner wheel would be loose more often in my experience but couldn't come off because of the outer wheel being tight.  The solution is to check the torque again soon after servicing a dual wheel.  Have you noticed it is always the rears that fall off?  If it was just the thread direction the fronts would fall off also.  Granted if they still used LH threads on the proper side they wouldn't fall off as often because the nuts wouldn't tend to spin off when they come loose.  If they are kept tight they don't fall off no matter which direction the threads turn.
Nothing has changed in the design here and wheels aren't falling off any longer.  I'm sure proper attention to torque has become mandatory.  I carry a torque wrench on my truck.
Joel McGregor

-----Original Message-----
From: VirtualVairs On Behalf Of Hugo Miller via VirtualVairs
Sent: Friday, March 06, 2020 8:31 AM
To: Byron LaMotte <bhlamotte at gmail.com>
Cc: VirtualVair <virtualvairs at corvair.org>
Subject: Re: <VV> Loose axle

Was it a stock wheel? Left-side wheel nuts (lug nuts) should be left-hand thread, and on quality cars in the UK (Rolls Royce, Bristol) they were at one time. This is to counter the effects of precession, which is too complicated to explain in a short e-mail, but it is the reason the left pedal on a bicycle will have a left-hand thread holding the pedal on, which seems counter-intuitive, as the rotation of the pedal around the shaft will tend to unscrew it. But the forces of precession act in the opposite direction, and they are reckoned to be stronger. Basically, if you imagine the pedal being very loose on a plain shaft with no bearings in it, the shaft will tend to 'walk' around the inside of the pedal as it rotates, and that is precession.
There was and still is a debate in the UK about what the government calls "Wheel-loss syndrome" on coaches. Typically of governments everywhere, instead of fixing the problem, they call it a 'syndrome'.
Basically, the story is this; traditionally, all British-built commercial vehicles used conical wheel nuts (like a car) to locate the wheels, and more importantly, they used left-hnad threads on the left-side nuts. So far so good. But then we adopted the European system of spigot-fixed wheels, using flat-faced nuts and, more importantly, they used right-hand threads all round. And the left rear (twin) wheels immediately began falling off all over the place. The government even launched a competition to find a way to keep the wheels on. Idiots! All they have to do is use left-hand threads and the problem goes away. I did try to explain about precession to the relevant govt dept, but I don't think they understood it. Anyway, our left rear wheels are still falling off, only now it's not an engineering problem but a syndrome.