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Lug nut seat lubrication

Lug nut seat lubrication

(OP)
thread68-351384: history of tapered lug nuts/bolts/screws

All,

I am a newbie here but I found the referenced thread very interesting and needed to follow up.

popeye427 obviously has credentials to put many issue to rest but I have heard conflicting
opinions on seat lubrication. Everything from hell NO to it's just fine.

Well, I recently used a very small amount of basic anti seize on my Silverado M14-1.5 wheel
lug nuts. Being paranoid I traveled around with my torque wrench for about two weeks. Checking
each day for any slippage. None found.


Why did I do it? I was getting grooves in the lug nut face from the contact with the wheel rim.
Now the lug nuts did have many changes and 200K miles, but always torqued to 140ft/lbs.

Am I risking my life?

D7 from Texas

RE: Lug nut seat lubrication

War story: Once upon a time the local ambulance fleet suffered a spate of wheels falling off, due to broken wheel studs. The cause was found to be that the weekly maintenance check included torquing the lug nuts up to the recommended installation torque.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Lug nut seat lubrication

You are not risking your life, but you are changing the friction conditions away from those validated by the manufacturer.

RE: Lug nut seat lubrication

Hi Greg,

So somehow torquing to spec resulted in a problem?
Or was some fancy space age lube involved?
Or, (I suspect) the weekly re-torque was in fact 1/8 turn tighter than as-found each time

RE: Lug nut seat lubrication

So, to answer the OP's question.

No, your life is NOT in danger.

First, lubing the lug nut seats results in a higher clamp load for the same amount of torque - and that increases the risk of the lug stud failing. But neither the lug nut wear nor the increased clamp load alone is enough to cause the lug to fail There are usually other factors that contribute.

And the wear groove in the lug nuts is not unexpected. I strongly suspect that the lug nuts are designed to wear before the wheel and the stud, since changing lug nuts is so much easier and cheaper.

RE: Lug nut seat lubrication

"Am I risking my life?"

Driving on public roads ?

Absolutely.

RE: Lug nut seat lubrication

(OP)
All,

Thanks for all the good responses. Bottom line is that a lug stud failure is low probability and I'm not risking my life from that event. Traffic in Austin Texas is the real killer.

With respect to the repeated torquing, I use a click type wrench and very carefully listen/feel for the click (an 1/8 of a turn (45 degrees) would actually be quite a bit).

On the clamp load comment, all else being equal, lubrication at the seat interface increases the tensile load on the stud correct?

Dennis

RE: Lug nut seat lubrication

Dennis said .... " On the clamp load comment, all else being equal, lubrication at the seat interface increases the tensile load on the stud correct?"

Correct. The torque spec is an indirect way to measure the amount of clamping force being generated. Another way to do this is by measuring the amount of stretch the bolt experiences. They sometimes use that 2nd technique on engine rod bolts

RE: Lug nut seat lubrication

In my experience, and I could be wrong,the only reason anti seize is needed is to protect the stud or lug from doing just that. I have only ever seen studs/lugs with it when installation was performed incorrectly in the first place, causing cross threading. Personally I would steer away from anti seize and if the need ever arises, replace the stud and lug affected. I error on the side of caution always.

RE: Lug nut seat lubrication

Somewhere along the line, I saw/read that it was recommended that after removing the lugs (assume for service; tire rotation, etc) or having new wheels installed, that the torque should be checked after 100 miles and that's it.

I agree that you're probably not putting your life at risk but I wouldn't want to be the person driving if the wheel did come off.

Tim Flater
NX Designer
NX 9.0.3.4 Win7 Enterprise x64 SP1
Intel Core i7 2.5GHz 16GB RAM
4GB NVIDIA Quadro K3100M

RE: Lug nut seat lubrication

If you are using the same lugs a re-torque is not needed every time the wheels are taken off. It you install new lugs, they should be checked within the first 100 miles (lugs heating up and expanding for first time and possible loss of retention)

RE: Lug nut seat lubrication

Tire shops generally have a printed notice saying cars with alloy wheels need the lug tightness checked after a hundred miles or so of driving.

A decade or so a professional acquaintance worked for his dad as a mechanical engineer. The company was quite successful making handsome "alloy" wheels for big rigs.
They were working hard to reduce the frequent re-torque requirement that alloys had.

RE: Lug nut seat lubrication

Quote (djglover7)

With respect to the repeated torquing, I use a click type wrench and very carefully listen/feel for the click (an 1/8 of a turn (45 degrees) would actually be quite a bit).

You'd be better served to mark the lugs and wheel with a paint pen and monitor them visually- remember that torque values are only meaningful if the wrench clicks while the fastener is actually moving.

RE: Lug nut seat lubrication

Hi jgKRI,

The witness mark across the interface would be an interesting test.

I'm about equally concerned with embedment of either the joint faces or the (now messed up) nut/wheel interfaces, which the witness marks would not reveal unless there was rotation too.
If a bolt is only stretched a few 0.001s of an inch it doesn't take much embedment to lose a bunch of clamping force and let the relentlessly carnivorous micromotion cascade to begin.
Even if there is no rotation of the nut, etc.
http://www.boltscience.com/images/boltf6.jpg

I'm thinking the stout integral belleville around each lug on most stamped steel wheels is THE reason alloy wheels loosen, and steelies don't.
http://i375.photobucket.com/albums/oo199/cole1230/...
https://www.cokertire.com/media/catalog/product/ca...

RE: Lug nut seat lubrication

Quote (Tmoose)

I'm about equally concerned with embedment of either the joint faces or the (now messed up) nut/wheel interfaces, which the witness marks would not reveal unless there was rotation too.
If a bolt is only stretched a few 0.001s of an inch it doesn't take much embedment to lose a bunch of clamping force and let the relentlessly carnivorous micromotion cascade to begin.

We definitely are in agreement that embedment could be a problem because of the very low amount of stud stretch.

However, checking for embedment with a torque wrench is still (potentially) fraught with error. When you tighten the lugs the first time, if you know what you're doing, the fastener is moving. Going back and checking them without applying additional turning angle just tells you that clamping load between the fastener and surface hasn't decreased more than the difference between the static and dynamic friction forces of the interface- which means in some cases, the clamping load could degrade by 30-40% or more before it was easily detectable by this method.

It's a catch-22.

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