antisieze compound on lugnuts??

[rpn453]

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No it will not. This is a common misconception people have with lugs. As long as the applied loads to the lug are less than the clamping force, nothing really happens.

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Are you sure? I know that the objects being clamped will not see any additional load until the fastener force is exceeded, but right now I can't visualize how a separating force wouldn't add more load to the fastener. I'll have to dig out my textbooks some time. The only reference I found on a quick search is in an ASME abstract. It is for a pressure vessel application, but I think it translates well to this topic:

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The amount of clamp load due to an externally applied separating force is determined for a boiled assembly in which the fastener is elongated past its proportional limit, while the clamped joint remained within its elastic range. After the initial tightening of the fastener, the joint is subsequently subjected to a tensile separating force, which further increases the fastener tensile stress into the nonlinear range. Such separating force will simultaneously reduce the clamping force in the bolted joint. Upon the removal of the separating service load, the bolted joint system reaches a new equilibrium point between the fastener tension and the joint clamping force. At the new equilibrium point, the fastener tension is reduced from its value at initial assembly, due to the plastic elongation of the fastener. The reduction in fastener tension translates into a partial—yet permanent—loss of the clamping load that may lead to joint leakage, loosening, or fatigue failure.

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Abstract from ASME Journal of Pressure Technology

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Also, the steel will become stronger (higher tensile strength) as it is cold worked by the plastic deformation (but it will become more brittle too).

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Oops. That should say "yield strength" instead of "tensile strength". It will still break at the same stress, but won't plastically deform again until the new yield stress is reached.

 

[XS650]

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No it will not. This is a common misconception people have with lugs. As long as the applied loads to the lug are less than the clamping force, nothing really happens.

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Are you sure? I know that the objects being clamped will not see any additional load until the fastener force is exceeded, but right now I can't visualize how a separating force wouldn't add more load to the fastener. The only reference I found on a quick search is in an ASME abstract. It is for a pressure vessel application, but I think it translates well to this topic:

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That's a difficult one to get your head wrapped around.

This
http://en.wikipedia.org/wiki/Bolted_joint
is by far the clearest explanation I have seen.

 

[jsharp]

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What I was taught...Torque values set for lug nuts are "dry". If you use anti-seize on the threads, you could over torque. Clean the treads and wipe off excess. Anti-seize should be used on the backside of the wheel (contact surface to the drum/rotor) so it doesn't weld itself.

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Torque values set for lug nuts are "dry" but clean and new are also factors. If torque is specified to achieve a given clamping force with clean and dry threads, it will be reduced if the threads aren't clean and dry, the plating is damaged or gone, the fasteners are somewhat rusty, etc. You've in effect undertorqued the fastener.

There's no risk using lubricated threads provided the torque is reduced.

 

[TBJ]

Would it not be better to tourque (impact wrech with stick) with a smaller rating then tourque up to the required number with a tourque wrench? But then I read this statement: "Torquing the bolt is notoriously inaccurate. Even with a calibrated torque wrench large errors are caused by dirt, surface finish, lubrication, etc. The turn of the nut method is more accurate, but requires additional calculations and tests for each application".

 

[Kestas]

rpn435, The explanation you dug out refers to applying strain to the clamped assembly, and is probably valid. (It is taken out of context and I'm not sure what information preceeded it.... probably talking about strain from temperature on a torque-to-yield assembly). My explanation refers to applying load (or stress) to the clamped assembly, and is also explained in the wikipedia link XS650 provided. One needs to be intimately familiar with interpreting stress-strain curves to fully understand this phenomenon.

I was hung up on the word "loads" when I quoted you, and I was compelled to correct the information. Even many of my colleagues are confused about this phenomenon.

 

[Kestas]

TBJ, there is a problem with torqueing to a lower load before applying final torque, especially if the two values are close. Torquing down a wheel bolt must be done while the nut (or bolt) is moving. This is to overcome the effects of starting friction, which is always greater than moving friction. So if you torque to a lower value, the subsequent starting friction may equal the higher value of the final torque.

 

[rpn453]

Thanks for the link, XS650. I do remember doing a lab on this topic a few years ago, and it's very easy to understand the picture with the spring and the solid block, but I wonder how many well the simplified model relates to certain real-life situations.

From that page:

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This model is only valid when the members under compression are much stiffer than the capscrew.

This is a simplified model. In reality the bolt will see a small fraction of the external load prior to it exceeding the clamp load, depending on the compressed parts' stiffness with respect to the hardware's stiffness.

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I agree, Kestas, that bolt theory wouldn't apply at all to the ASME reference I provided, since that would likely be for a gasketed flange on a pressure vessel where the fasteners are far stiffer than the gasket. So the question is: can a person assume that the clamped area of an aluminum wheel, or even a thin steel one, is much stiffer than the steel studs? After all, if a sample of aluminum and steel have the same cross-sectional area, steel is about four times as stiff. For a steel wheel, the extra length of the bolt would make it stretchy relative to a thin piece of steel being clamped, but the steel is tapered up at the clamp joint which may give it some flex. I wonder if aluminum wheels are more likely to come loose because of the metal's low elastic modulus?

Even if the clamped component is much stiffer than the fastener, there is still some extra load on the fastener when an external load is applied. When the fastener is already operating in the plastic range, any amount of extra load it sees will cause further permanent deformation. So, for now, I'm standing by my initial thoughts on this one: that driving with a freshly overtorqued lugnut will cause further plastic deformation of the stud but likely not much; usually not enough to cause it to loosen right off. If you were operating in the elastic range, the extra load would not affect the stud.

 

[TallPaul]

Only 100% sure solution to this dilemma is to install new studs and lug nuts every time you change a tire.

 

[XS650]

Kestas, typically the area of clamped material is so much larger than the cross sectional area of a bolt that the clamped material is still many times stiffer than the bolt.

There are exceptions, but I seriously doubt that wheels are one of them.

 

[9c1]

This may or may not bear on the discussion of wheel stiffness, but I have noted with steel wheels the area around the lug nuts does deform as the nut is torqued.

A close look at the center of modern steel wheels will reveal that they are formed such that the portion that clamps against the spindle, or brake rotor center, is not directly under the nut. I suspect, unless the lug nut is grossly over tightened, the deformation that takes place is not in the lug stud, but in the face of the center web of the wheel. None the less one would not want to tighten the lug nut enough to force the wheel into the plastic range.

All that said, I haven't had the opportunity to observe closely aluminum wheels, so I don't know if the same mechanism is at work there.

 

[obbop]

Here's one guy's opinion. Also, check out his blog. I found it interesting.

http://brakeandfrontend.blogspot.com/

"NO ANTI-SEIZE ON WHEEL STUDS OR LUG NUTS

If you apply any friction modifying substance, like oil or anti-seize, to the wheel stud threads, it is going to change the measured torque values. With less friction on the threads, the torque values increase. So, when you tighten a wheel to 85 ft/lbs, it may actually be torqued at 95 ft/lbs (this includes torque wrenches and sticks). The increase in force will mean that the studs will stretch under the increased torque. This stretching can lead to metal fatigue, changes in thread geometry and the possible failure.
This can be a very significant problem, and I apologize for letting it slip. But, in doing some research, I encountered another aspect of anti-seize on wheel studs that can be an even greater problem. If you encounter a vehicle with anti-seize on the wheel studs, be very careful. Take time to explain to the driver why anti-seize is bad and how it can cause problems. Also, advise them that there is a potential for failure during normal service. You should also put it on the repair order.
Is there a right way to use lubricants around the wheel? Yes, but it has to be a high-temperature lubricant used only in a very light coating. First, a high-temperature lubricant can be used where the hub goes through the center of the wheel. Many vehicles use the hub to center the wheel. These “hub-centric” designs can benefit from a very light coating.
On some conical lug nuts, you can put a light coating on the seating surfaces of the cone, while avoiding any contamination with the threads. This coating can prevent corrosion. Thank you Ed, for setting me straight.
But, in a 1994 Ford TSB they did say it was alright to use anti-seize on studs for some F-250 and 350 trucks, these studs and lugs are so stout and strong, a few extra or less pounds of torque are of little consequence."

Copied and pasted out of fear that for whatever reason the linked-to material will disappear, as has happend in the past. All the writing within quotes is from Andrew Markel and I encourage all to visit his blog.

"Andrew Markel is a former technician and service writer and he brings this practical knowledge to the Brake & Front End team as editor."

 

[Kestas]

rpn453, You and 9c1 are good to point out the taper in the steel wheel clamp area. This dishing of the seating surface is designed into the wheel to act as a spring and ensure the clamp load is maintained in case there is some "bedding-in" of the joint, as can occur with alloy wheels. This is why steel wheels don't need retorqueing.

Obbop, we did some testing in our lab to study the effect of antiseize on wheel bolts, as it relates to heavy truck wheel bolts. Firstly, we specify two drops of oil on each stud before running down lug nuts. We find in the field that some owners/mechanics get too "happy" with antiseize, and this can cause problems. If slathered on the thread and seating surface under the nut, the wheel bolt can easily fracture when torqued to specified values. A light coating of antiseize on the threads does not pose a problem. As you can imagine, it's the additive effect of lubing the threads and seating surface that markedly removes the friction needed to match the specified torque.

Personally, I add just a light coating of antiseize to lug nuts when I wrench on cars. Here in the rust belt, I've seen too many lugs that are really crunchy when you try to remove them, and in some extreme cases need to be replaced because of damage from sticktion. Wheel stud bolts are safety critical items and need to be nothing less than perfect.

 

[1sttruck]

On newer vehicles the makers seem to be using anti-seize on the threads, although it's a dry compound. I change to winter tires on all of the vehicles each year and have never observed a problem with loose lug nuts or over torqued ones either. On older vehicles I have observed problems with studs and lug nuts in poor condition, parts of threads coming off and such, problem that I don't see with my studs that have anti-seize on them.

A former coworker received a call from her daughter one day, as she couldn't get the lug nuts off to change a tire. The coworker went out to help and she couldn't get them off either, and even her largish husband in good shape had a hard time getting them off, on the side of a busy road in a steady rain.

A little bit of anti-seize goes a long way; brush a light coat on the stud, wipe the stud off, and keep it off of the interface between the wheel and the lug nut.

 

[Kestas]

The compound is Dacromet, as I mentioned on the first page of this thread.

 

[swalve]

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On newer vehicles the makers seem to be using anti-seize on the threads, although it's a dry compound. I change to winter tires on all of the vehicles each year and have never observed a problem with loose lug nuts or over torqued ones either. On older vehicles I have observed problems with studs and lug nuts in poor condition, parts of threads coming off and such, problem that I don't see with my studs that have anti-seize on them.

A former coworker received a call from her daughter one day, as she couldn't get the lug nuts off to change a tire. The coworker went out to help and she couldn't get them off either, and even her largish husband in good shape had a hard time getting them off, on the side of a busy road in a steady rain.

A little bit of anti-seize goes a long way; brush a light coat on the stud, wipe the stud off, and keep it off of the interface between the wheel and the lug nut.

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Are there any differences in wheel torque for newer vehicles?

How much more torque would actually be applied when using anti-seize? How many more degrees of rotation of the wrench? I think not using a torque wrench is far more "dangerous" than a little anti-seize.

How are the torque values determined by the manufacturers, anyway? I think we're way over thinking this.

 

[Shannow]

I prefer tightening through an angle over torque tightening anyday...never seen any angular tightening specs for wheel nuts (although Dad used to argue "tight plus quarter turn").

At work, we do nuts up to 200ftlbs (finger tight). Then shove an induction heater down the stud, and heat it till it's not quite red. Rotate through 60 to 140 degrees depending on stud length (0.15% strain, and 6 threads per inch).

Alternative method on other items is to attach a hydraulic ram to the stud, apply a given load to stretch the stud, and screw on the nut. Release ram pressure, and bingo perfectly tightened assembly.

Never seen one come loose to date.

 

[obbop]

"At work, we do nuts up to 200ftlbs (finger tight)"

Do NOT, repeat, do NOT anger this man!!!!!!!

 

[alreadygone]

Any of the nay-sayers got documentable case of positive damage, lost wheels,etc. caused by antisieze? Auto lug nuts only.

Bob

 

[Kestas]

Shannow, I'm curious, what application uses this recipe you described?... building skyscrapers?

 

[NYEngineer]

I've always put the slightest bit of nevr sieze on all my vehicle's wheel studs. Just barely enough to slightly color the stud silver. It stays on forever and I've never ever had a lug nut come loose. Never had one stick either. I also torque the lugs to the factory spec since there's hardly any on there anyway.