aussie_paul wrote:

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Thoughts re lubricating wheel nuts?

Aussie Paul. 

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 Hi Paul.

I have been cleaning my wheel studs and nuts and applying very small amount of oil for ever (56 years). With the truck I carried a wire brush and boy did I cop some ribbing, pull the dip stick out to get some oil.

I would not pull a wheel off just to lubricate the nuts.

Wouldn't Loctite be better? My car's manual says NEVER lubricate the wheel nuts. Whereas Loctite keeps the thread free of dirt and rust, locks the nut and makes it easy to remove once it's seal is broken. 

The torque values for tightening nut is always based on dry threads. As soon as you use liquids (oils or locktite) on the threads you need to calculate a new torque value. Just clean the threads off and tighten them as the engineers do.

Assuming we are discussing wheel nuts only as opposed to tightening nuts in general, some of the statements here indicate general. There are two sides to every story. I for one lubricate the studs, then do them up using wrist torque, or as I did this week when getting two new tires, checked how the fitter tightens the wheel nuts getting them to torque them up. I worked as a motor mechanic at one stage, and had to use a rattle gun for the job. Now a rattle gun has three settings 1? 2? and 3?, in other words no idea how tight the nut is being done up. With practice and feel one can avoid over tightening. But if you get a new guy on the job who doesn't give a dam, he can tighten the studs up to shearing point.
So if you take your car into be serviced and for tire fitment, not doing your own thing, then no lubricant, but if you do your own thing, then lubricant is a good thing. Any metal surface moving against another should have lubricant.
I agree torque values are different, but lubricant helps prevent the threads from binding, and helps stop corrosion on the exposed threads.

iana wrote:

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Assuming we are discussing wheel nuts only as opposed to tightening nuts in general, some of the statements here indicate general. There are two sides to every story. I for one lubricate the studs, then do them up using wrist torque, or as I did this week when getting two new tires, checked how the fitter tightens the wheel nuts getting them to torque them up. I worked as a motor mechanic at one stage, and had to use a rattle gun for the job. Now a rattle gun has three settings 1? 2? and 3?, in other words no idea how tight the nut is being done up. With practice and feel one can avoid over tightening. But if you get a new guy on the job who doesn't give a dam, he can tighten the studs up to shearing point.
So if you take your car into be serviced and for tire fitment, not doing your own thing, then no lubricant, but if you do your own thing, then lubricant is a good thing. Any metal surface moving against another should have lubricant.
I agree torque values are different, but lubricant helps prevent the threads from binding, and helps stop corrosion on the exposed threads.

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 In other words - "No lubricant" is the "Default" setting ..... to protect against  inexperienced operators........ I agree.

KJB wrote:

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Radar wrote:

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aussie_paul wrote:

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Thoughts re lubricating wheel nuts?

Aussie Paul. 

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 Hi Paul.

I have been cleaning my wheel studs and nuts and applying very small amount of oil for ever (56 years). With the truck I carried a wire brush and boy did I cop some ribbing, pull the dip stick out to get some oil.

I would not pull a wheel off just to lubricate the nuts.

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Same here Radar - on trucks , trailers , earth movers , racing cars ......I have always  (56 years ) used Anti-seize (Coppercoat )  on clean threads . lets the thread do its job without seizing or galling  . Undoing is easy - release the tension with a bar  and the the nut spins off , no rust , dirt , scale  ....or swearing. 

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 I use the same thing, Coppercoat. When I was in the army, I was moonlighting at Qantas Base in Sydney, for a 2 year period, and we used Coppercoat on all the wheelnuts on the planes, so started doing it on my vehicles. It was also done in the army, but using other grease, usually Marine. I still a half a kilo, of Coppercoat today, and do all the wheels I have on all my vehicles. After I put it on and do the nuts up, I wipe off the excess, so no dirt and grit, attaches to the outside threads.

The quite common and very cheap sunraysia wheel and any other Chinese wheel has soft steel. I found this out when I nearly lost a wheel. I was lucky to hear the wheel wobble as I don't have a radio or any other noises in my car. 5 new studs needed and a new wheel.

So I use a tension wrench on the 10 nuts before heading off from camp and often a nut will need such tensioning up.

 

Only takes 30 seconds

Tony

 

-- Edited by Eaglemax on Saturday 5th of June 2021 04:33:16 PM

Izabarack wrote:

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........  I am yet to see a car manufacturer requirement to use dry threads.    ......

-- Edited by Izabarack on Saturday 5th of June 2021 04:04:26 PM

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 The Ford Ranger Owners Handbook specifies no lubricant.

 

For those who recommend lubricating the threads, how do you determine the required torque?

 

If that article is from the Ford Ranger manual, then it does indeed specify no lubricant, but it says nothing about altering the torque value, but says that lubricant can cause the wheel nuts to come loose. This is because the application of lubricant is inserting a layer between the surfaces, as this layer is squeezed out, or dries out the space it occupied is reduced, and so the tightness of the nuts is reduced. "This can cause the lugs to loosen while driving" unquote.
Its more about litigation than tightening the wheel nuts, if the car companies said you can lubricate the studs etc, and a wheel came loose, the company could be taken to court for writing that. Its better to say nothing, they don't care about sheared studs, or the studs being so corroded they can't be removed.
My post above was implying that about having lubricant on the cone surfaces between the nuts and rims.

Peter_n_Margaret wrote:

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It is wonderful that we have people here who know more about these things than the engineers who designed the vehicles. 

Cheers, Peter

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 Hmm 

Possibly or possibly not !

I think there are several things to add. Vehicle wheel studs and nuts are usually well formed and high tensile steel, this reduces the likelyhood of galling and pickup. Perhaps the caravan studs and nuts are not made of such good stuff and are more likely to gall and sieze.

I have always lubed the studs and nuts on vehicles I use and also the ones I worked on when I was a plant mechanic. I always hand tightened them. Never had any problem over many many years. I will say these days on my new car i usually just give them a spray of WD which is only just lube and some preservation from rust etc. 

With regard to lubing the taper seat. It was my teaching that you never use anything on a taper that you want to 'lock' and transmit power. But I do not see that is the case with the tapered seat on a wheel nut. With some wheel nuts if you do not lube them you will never get them off. I have broken factory spanners removing some taper nuts. So I have always lubed them with molly grease. Hand tightened with a suitable wrench whatever the size.   

Just for interest I have spent some weeks in the past doing research on torque applied to nuts on roof bolts vs tension developed in the bolt. Using different nut 'fits' and bolt machine 'fits' to determine safety limits. Then also using different washers under the nuts including mild steel, hardened steel, and roller thrust washers to investigate the variations in the tension vs torque applied.  This was all to do with seeing how the variables could be controlled because the mine roof bolts are fitted by a machine in a very short time frame. The other end is machine inserted in a drilled hole with quick setting epoxy that sets in a minute before the bolt is tightened ! 

Cheers Jaahn   

Always used graphite grease . The taper of the nut helps, assume the tighter the better the taper works . Our issue has been undoing the nuts !

Using a (torque) wrench causes two inclined planes to slide against each other and ultimately stretch the bolt.     Lubricated threads more certainly achieve the design spec in the absence of confounding factors like friction and metal galling giving false results.    The wing bolts on DC3 aircraft are tensioned using a micrometer, as an example of length increase showing the action of torquing a bolt.    Metallurgy might be a reason for relying on dry torquing to achieve design torque, if the metal is slippery enough but specifying torque is a critical safety consideration, so, my perspective is that specified torque values can only be achieved if the bearing surfaces can move against each other freely.   Without knowing what exactly is going on at the bearing surfaces inside a thread dry threads must be suspect.   In the case of a Ranger, close enough must be good enough.

 

Manufacturers can use dry unlubricated threads for 2 reasons:
1 Their environment is clean and they are using new products, and
2 To use a lube on the threads could be messy and more expensive.

Tightening threads in the real world is a totally different matter. The only way you can get a reliable tension into a bolt is to physically measure the bolt extension (typically with a dial gauge). This then allows you to assess the actual tension in the shank of the bolt. That is impractical for all but critical bolt installations. The next best method is to use lubrication. Light machine oil is usually recommended although a thin smear of grease on wheel studs will do just about as well. Lubricating the threads reduces the variability of the friction component, and makes for a more reliable clamping. Tightening a dry thread the friction can vary enormously. Where manufacturers specify dry tightening, they have probably made allowances in the recommended torque that the tension in the bolt shank will not be excessive.

Interestingly, I have checked the workshop manual for my vehicles (both Mitsubishi) and they give a tightening torque but make no reference to lubricating the threads. Therefore I assume that they are talking about tightening the threads dry. The figures given were 110 Nm (81 ft-lb). Years ago I had a Triumph 2000 which the workshop manual specified torques for every bolt in the car. They said 60 ft-lbs for the wheel nuts, but lubricated threads. I tightened the bolts to this figure, and then went round and tightened them again by hand because to me this felt far too loose. However, the 60 ft lbs figure would probable give the same bolt tension as the 81 ft lbs of my Pajero, the Pajero having 6 bolts vs 4 of the Triumph.

Peter_n_Margaret wrote:

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It is wonderful that we have people here who know more about these things than the engineers who designed the vehicles. 

Cheers,

Peter

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Have to agree on that point. A bit like "Caravan polish" information