No grease on lug nuts

Don Phillipson wrote:
> A garage mech told me today never to grease
> the threads of wheell lug nuts, because it makes
> it easier for them to back off i.e. become loose.
> Opinions?
>
Never grease lug nuts.
It causes over tightening that leads to warped rotors.

On May 24, 4:29 pm, Paul <[email protected]> wrote:
> Never grease lug nuts.
> It causes over tightening that leads to warped rotors.

A wet torque is better than a dry torque. If the lug nuts on a car are
supposed to have a torque of 75 ft lb, how does applying grease make
you torque them to more than 75 ft lb?!?! Get grease in your eye and
can't see the dial, or get it on your hand and slip off before you
hear the click?!?! Please, what are your suggestions for anti-seize,
WD40, CRC and oil. Penetrating oil allowed?!?! So, when I put oil on
my squeaky wheel barrel tire, I ‘m actually tightening it?!?!

idbwill wrote:
> On May 24, 4:29 pm, Paul <[email protected]> wrote:
>> Never grease lug nuts.
>> It causes over tightening that leads to warped rotors.
>
> A wet torque is better than a dry torque. If the lug nuts on a car are
> supposed to have a torque of 75 ft lb, how does applying grease make
> you torque them to more than 75 ft lb?!?! Get grease in your eye and
> can't see the dial, or get it on your hand and slip off before you
> hear the click?!?! Please, what are your suggestions for anti-seize,
> WD40, CRC and oil. Penetrating oil allowed?!?! So, when I put oil on
> my squeaky wheel barrel tire, I ‘m actually tightening it?!?!
>
I disagree. We were taught in FoMoCo classes to never oil, grease, or
antisieze
nuts and bolts without specific instructions from the mfg to do so.
Yes, the torque is the same but the stretch is different.
Your wheel barrel does not have disk brakes that often run very hot.

On May 24, 5:34 pm, idbwill <[email protected]> wrote:
> On May 24, 4:29 pm, Paul <[email protected]> wrote:
>
> > Never grease lug nuts.
> > It causes over tightening that leads to warped rotors.
>
> A wet torque is better than a dry torque. If the lug nuts on a car are
> supposed to have a torque of 75 ft lb, how does applying grease make
> you torque them to more than 75 ft lb?!?!

Errr..it doesn't force you to do anything, but a 75 ft-lb "wet" torque
will generate a higher tensile value in the male fastener than will a
"dry" torque of 75 ft-lb.

The torque reading is simply a measure of the frictional resistance to
tightening the fasteners. Various combinations of dry, lube, plating,
all give different torque-tensile relationships.

idbwill wrote:
> On May 24, 4:29 pm, Paul <[email protected]> wrote:
>> Never grease lug nuts.
>> It causes over tightening that leads to warped rotors.
>
> A wet torque is better than a dry torque. If the lug nuts on a car are
> supposed to have a torque of 75 ft lb, how does applying grease make
> you torque them to more than 75 ft lb?!?! Get grease in your eye and
> can't see the dial, or get it on your hand and slip off before you
> hear the click?!?! Please, what are your suggestions for anti-seize,
> WD40, CRC and oil. Penetrating oil allowed?!?! So, when I put oil on
> my squeaky wheel barrel tire, I ‘m actually tightening it?!?!
>

Doesn't quite work like that.

Unless otherwise 'specifically' stated, all torques are given for dry
components.

The difference can be the bolt being rally tight with the proper dry
torque to actually snapping with a wet torque.

If you want to mix, there are charts around for the equivalent wet to
dry torque for clamping force. Something like a 60% difference.

Mike

> never to grease
> the threads of wheell lug nuts, because it makes
> it easier for them to back off i.e. become loose.
> Opinions?

a definite and absolute NO. Never put grease or oil on them.

"Don Phillipson" <[email protected]> wrote in message
news:g19rau$641$2@theodyn.ncf.ca...
>A garage mech told me today never to grease
> the threads of wheell lug nuts, because it makes
> it easier for them to back off i.e. become loose.
> Opinions?

Well, that concept is horseshit...

You dont use grease because the specifications are made of clean dry
threads, and
you will exceed the acceptable tension of the bolt if you use grease without
compensating
in torque readings.

IF you compensate by decreasing the torque for greased threads, then you can
get the same, or nearly the same bolt stretch (tension) by using greased
bolt threads. This is the true clamping force.

I have never seen a bolt loosen which has been properly torqued in the first
place, whether
lubricated or not. If this were the case, you couldnt keep connecting rod
bolts tight.

That is a myth, an old mechanics tale, BS.

> "Don Phillipson" <[email protected]> wrote in message
> news:g19rau$641$2@theodyn.ncf.ca...
>>A garage mech told me today never to grease
>> the threads of wheell lug nuts, because it makes
>> it easier for them to back off i.e. become loose.
>> Opinions?
>
> Well, that concept is horseshit...
>
> You dont use grease because the specifications are made of clean dry threads,
> and
> you will exceed the acceptable tension of the bolt if you use grease without
> compensating
> in torque readings.
>
> IF you compensate by decreasing the torque for greased threads, then you can
> get the same, or nearly the same bolt stretch (tension) by using greased bolt
> threads. This is the true clamping force.
>
> I have never seen a bolt loosen which has been properly torqued in the first
> place, whether
> lubricated or not. If this were the case, you couldnt keep connecting rod
> bolts tight.
>
> That is a myth, an old mechanics tale, BS.

So, what about greasing the face of the nut, where it presses against
the wheel?

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Calab wrote:
>> "Don Phillipson" <[email protected]> wrote in message
>> news:g19rau$641$2@theodyn.ncf.ca...
>>> A garage mech told me today never to grease
>>> the threads of wheell lug nuts, because it makes
>>> it easier for them to back off i.e. become loose.
>>> Opinions?
>>
>> Well, that concept is horseshit...
>>
>> You dont use grease because the specifications are made of clean dry
>> threads, and
>> you will exceed the acceptable tension of the bolt if you use grease
>> without compensating
>> in torque readings.
>>
>> IF you compensate by decreasing the torque for greased threads, then
>> you can get the same, or nearly the same bolt stretch (tension) by
>> using greased bolt threads. This is the true clamping force.
>>
>> I have never seen a bolt loosen which has been properly torqued in the
>> first place, whether
>> lubricated or not. If this were the case, you couldnt keep
>> connecting rod bolts tight.
>>
>> That is a myth, an old mechanics tale, BS.
>
> So, what about greasing the face of the nut, where it presses against
> the wheel?

The contact between those two friction surfaces creates some of the torque.
To get the same 100 ft lbs, the nut will have to be turned more creating
more stress and stretch.

"Paul" <[email protected]> wrote in message
> The contact between those two friction surfaces creates some of the
> torque.
> To get the same 100 ft lbs, the nut will have to be turned more creating
> more stress and stretch.

If you can measure bolt elongation (and you can), you can attain the
required
clamping force irrespective of the observed torque..

Torque in foot pounds is only relevant if the condition of the threads and
the
friction between the bolt face and metal surface are within the bounds which
the
engineer intended. (A nut that is a few thousandths of an inch narrower in
bore or
wider will also affect this.)

This does not mean that you cannot grease the threads and achieve a
perfectly useful
clamping force, but you will not do it at the same observed torque that you
did with
dry threads.

Some years ago, I searched the internet and found the concensus that to use
greased
threads, you need to drop the torque figures by about 20-25 percent. I have
no idea
whether this is valid or not.