Weedpharma wrote:

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Surely lubricants on the studs reduces the friction and therefore reduce the force needed to turn the nut. This in turn means the nut goes harder against the wheel and applies more stretch to the bolt.

Conversely, the lubrication would make it easier for the nut to unwind if not fully done up.

Weedpharma

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 Yes it does mean that the lubricant reduces the friction, that's the point of lubricating it, however when you are using a torque wrench to tighten them you will only get the correct tension on the bolts therefore no the nut is not tighter against the wheel and no it will not stretch the bolt, this is the very reason for using a tension wrench to tighten the wheel nuts in the first place. 

and yes it would make it easier for a lose nut to come undone but..... If you have done them up to the correct tension they won't come undone making this a mute point and indeed the whole reason for using the tension wrench to tighten them in the first place .

woody 

Back in the day, (In the Fitting department), only specific threads called for lubrication prior to using a torque wrench

These were mainly large diameter threads, of very high torque, where the only option was to use a hydraulic torque wrench, or mechanical torque multipliers

When a manufacturer (of a machine) stipulated that lubricant was required, they also stipulated the torque to be used.
The torque given was around 70% (don't quote me on this number, it was a long time ago), of the normal torque range, from the tables of that type/class/size/pitch of thread

The reason was that the torque wrench relies on the friction of, both the face of the nut/bolt, and the friction of the loaded side of the thread

Hope that I am not fanning the flames

Tell me one tyre place who uses a torque wrench . Tat tat tat. Done with compressor air gun !! Does way more damage . The main part it centralised . Plus it's the question of pissy std wheel brace to undo some wheel nuts . I purchased a 50 to1 torque multiplier for Fuso bus / Motorhome . No way in the world could you undo these nuts with out it .. Besides we have to consider we ARE older than we think !! Not many Bow repaires in Pimbera ! Lol

PeterD wrote:

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Aus-Kiwi wrote:

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Tell me one tyre place who uses a torque wrench . 

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 I have been to a couple of Bridgestone tyre outlets where they finish off the tensioning of wheel nuts with a torque wrench.

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Tyre Power Bunbury WA - 2014

Purchased one only tyre for my motorhome, without any input from me, they used a long handle half inch drive torque wrench, to torque at 150 ft lb

Thinking that this must be the setting, and that my normal torque wrench was on the small side, at 150 ft lb maximum.

I purchased a long handle one which is good for up to 250 ft lbs (same as what the tyre place used)

I have since found, peeking in a manual, that it is supposed to be

160 Nm for 14mm bolts (118 ft lb) or
180 Nm for 16mm bolts (133 ft lb)

I was in the mechanical trade and my hobby is restoring cars and motorcycles so I speak from experience , I use a tension wrench on cylinder heads and that's it, you can easily over tension studs with a tension wrench, and when you undo it you will sheer the stud, grease the stud you will have something that is over tensioned and if it did start to loosen up big trouble, a greased wheel stud in my view is absolute stupidity.

Just tension them up firmly ,and check them regularly and you will find that's even easier without a tension wrench....

Gday...

OK - I apologise this has a yankee accent ... but it gives some rational for and against -

http://www.tirereview.com/its-really-all-about-lug-nuts/

To save you scrolling to find the article ... this is it -

Lubrication

There is a great deal of argument is whether to lubricate lug threads. Some swear by the use of some form of anti-seize on the threads, whether lithium grease, WD-40, motor oil or Teflon spray. The idea is to prevent rust and make it easier when it comes time to remove the lugs. Others recoil in horror, saying that lubing the threads will result in overtorqued nuts, or that the lubrication will cause the nuts to work themselves loose.

Manufacturers, engineers and other industry experts seem to unanimously oppose using lubrication. On the other hand, some customers, DIYers and self-appointed Internet forum experts claim to have used thread lube since the very dawn of time with nary a problem.

My own opinion is more nuanced. I disapprove of lubricating threads in general, unless they are badly rusted. Most lug bolts and lug studs are coated with a substance intended to prevent rust, but certain makes and models seem to be much more vulnerable to rust than others (Im looking at you, Volvo).

In that case I can see applying a small amount of lubricant to prevent further corrosion, but only after carefully cleaning the rust off the threads with a wire brush. In most cases, however, I would simply ensure that the threads are clean and not bother with lubrication.

If you do apply lubricant, make sure to do so carefully and only to the threads. Never allow any lubricant on the mating surfaces of the nut or the lughole of the wheel.

Much of the stickiness brought about by proper torque comes not from the threads but from the contact between mating surfaces. Even a thin film of oil between those surfaces can create a hydraulic barrier, preventing proper torque from being applied. This can also make it easier for the nut to work itself loose.

Either way, its always best to get that customer to return in two weeks to check the lug nuts for tightness if any lubricants are used.

Well, thus ends this months sermon. Now get out there and go nuts!

Cheers - John

If it was all that important there would be a torque wrench supplied in the tool kit of every car. (you could use it to do your caravan /trailer wheels as well! )

KB