Anti-sieze on lugs...

[M.D. Holloway]

Anyone ever hear of not wanting to use an anti-sieze on lugs because it would mean you would actually torque them down beyond the recommneded ft-lb and possibly strain the treads resulting in premature failure?

[mossguy]

Yes, I have heard this.

[pwd72s]

Nope...never heard that. In the material I've read from Stoddards, they suggest using it...Bostik NEVER-SEEZ regular formula. Torque to 96 foot pounds in an every other lug pattern.

Never had a wheel come off doing this...

[Flieger]

I think the torque values are based on lubricated threads?

[pwd72s]

I think so...lube the threads and you'll not be one of those posting about a snapped in half alloy lug nut, wondering how to remove the broken piece. Be sure to put a very light coating on the curved face of the lug nut as well...that's where much of the galling happens that produced those snapped off lug nuts.

[M.D. Holloway]

Bolt Science Web Site

[Flieger]

Originally Posted by pwd72s

I think so...lube the threads and you'll not be one of those posting about a snapped in half alloy lug nut, wondering how to remove the broken piece.

Does the owner's manual have this information?

[island911]

Originally Posted by LubeMaster77

Anyone ever hear of not wanting to use an anti-sieze on lugs because it would mean you would actually torque them down beyond the recommneded ft-lb and possibly strain the treads resulting in premature failure?

people say all kinds of things.

I will say that if the threads and bolt face have lube, that the longitudinal stress on the bolt can be increased for a given torque.

[pwd72s]

Originally Posted by Flieger

Does the owner's manual have this information?

I dunno..the owners manual left here with the car.

[Flieger]

Originally Posted by island911

people say all kinds of things.

I will say that if the threads and bolt face have lube, that the longitudinal stress on the bolt can be increased for a given torque.

I don't see how applying lube to both components will be all that different than applying lube only to the threads.

[island911]

For a lube thread only... think of the forces of a door-stop (wedge) pushed between a top surface of say aluminum oxide (sand paper) and a bottom surface of say, oiled ice.... Does that help?

...it would be as if the ice was a mirror symmetry in an FEA model.

[Flieger]

But both the door and floor would be coated in oil if you had lubed the threads. You don't only lube one side of the threads. That would require a tiny brush and way too much patience.

[island911]

Also of note is that a bolt face is of a larger radius than the threads (better mechanical -leverage- advantage with dry friction there, than on the threads)

[Flieger]

And the main thing is that the torquing is done as Porsche prescribed. If they say to use lubrication, then use lube. The difference between applying lube to nut and lug compared to only lug should not be significant. It should be within the margin of error in friction coefficient the Porsche engineers calculated for.

[Flieger]

Originally Posted by island911

Also of note is that a bolt face is of a larger radius than the threads (better mechanical -leverage- advantage with dry friction there, than on the threads)

That is true, you are referring to when the ball contacts the wheel, so you mean lubricating the face of the nut, plus the lug's threads. I thought you were only talking about the threads of the nut and the lug.

[island911]

Originally Posted by Flieger

But both the door and floor would be coated in oil if you had lubed the threads. You don't only lube one side of the threads. That would require a tiny brush and way too much patience.

n'no, the doorstop would be the whole fastener in this Gedankenexperiment. (and the door fixed)

[island911]

Originally Posted by Flieger

And the main thing is that the torquing is done as Porsche prescribed. If they say to use lubrication, then use lube. ...

Yep. They use empirical methods smartly.

Lubemasters post I took as a more general idea about the potential of over-stressing fasteners from std torque, but really good lube. ...you know, the type of stuff found in the physics closet next to the massless ropes, and under the frictionless pulleys.

[Flieger]

Originally Posted by island911

Yep. They use empirical methods smartly.

Lubemasters post I took as a more general idea about the potential of over-stressing fasteners from std torque, but really good lube. ...you know, the type of stuff found in the physics closet next to the massless ropes, and under the frictionless pulleys.

That always peeved me in vibrations class. Assume this and that... And what do you know, it ends up as a nice linear differential equation. But are we really talking about a real situation?

That is why you test. If the model is 'close enough' then go ahead and suspend disbelief and use it.

[Flieger]

Originally Posted by island911

n'no, the doorstop would be the whole fastener in this Gedankenexperiment. (and the door fixed)

I am looking at this from the perspective that if you have two surfaces in contact, lubricating one is just as good as lubricating both, since the lube just needs to end up at the (singular) interface anyway.

[RWebb]

Bruce Anderson wrote in his Pano or Excl. column that the magic Porsche anti-sieze does not change torque values... I forget which of the Optimoly compounds he said to use.

Bump this thread after 5 pm and I'll try to look it up when I'm home.