 | Home > Wheels & Tyres > To grease my nuts or not to grease - and a surprise! |
 
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| Matt110 Member Since: 29 Jun 2014 Location: UK Posts: 673  
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So you'll get two answers to this question.
The first one is this: "I've always put grease on my nuts, they've always been OK and they've never fallen off and they're SO MUCH EASIER to get off when you want to undo the nuts. Definitely put grease on them". Followed by discussion on whether to put on copper slip, or normal grease, whereupon the general consensus will be copper slip, and off you go. The second one is is: Engineers size joints based on a torque to failure test. We basically run the nuts against the stud to failure, plotting torque vs rotation of the joint as you go. What that gives you is a nice run up the graph at 45 ish degrees (graudally levelling off very slowly), followed by a levelling off of the graph quickly which means the joint is elongating, and finally, the graph dropping to zero torque per angle as the joint fails. It's normally designed to fail by NOT stripping the thread, so that you can't ever have a joint that has the appearance of being done up but is actually failed. The essence of that is that you make sure that the torque that you are specifying is appropriate and doesn't elongate the bolt/stud (unless you need to - that's a whole other ball game I won't get into but if you elongate the joint slightly you sometimes get slightly more clamp on the joint even though it's technically elongating and failing - that's where a torque plus angle specification comes from on a joint, and the bolt must ALWAYS be replaced if it's ever undone). The problem with greasing your nuts is this: it changes that curve I've just described. So you grease your threads, do the joint up, and as you get to the published torque, you get a big bang and the joint fails (stud snaps in half normally). It's because you've got so little resistance to the turning, i.e. the torque is so low to turn the wrench, that the joint gets to a much much higher clamp before it gets to the rated torque and the wrench clicks. So you then think "OK, i'll just do it at a lower torque then". And that would be OK except for the fact that what torque do you pick? You need one that is less than original, but high enough to be at the same point on the clamp load graph as the original joint. Get it wrong in one way, and the wheel WILL fall off in the end. Most are just lucky. Get it wrong the other, you'll need a new stud. Auto manufacturers, mass production ones at the very least, never ever put lubricant on a joint unless it's a patch lock, in which case thats designed into the torque number that's specified. The reason is that in production, lubricant on a joint is completely unrepeatable. You can't apply it reliably, you can't guarantee the next bloke or lady along the line will do the same amount, or same way...... the only repeatable way is dry. So that's what is done. Same with service. They're always (supposed) to be dry. Fairly obvious which side of the fence I sit on!  
The only place for lubricant, and even then only copper slip, is a fine coating on the hub face to make sure you can get the wheel off. Hope that helps. |
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30th Nov 2020 5:37pm |
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| rustyredwreck Member Since: 16 Jan 2020 Location: Oxfordshire Posts: 24  
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Hello Matt,
Thanks for the comprehensive response - as an engineer myself (civil engineer - we tend to use larger hammers to fix things) I appreciate and understand the explanation. So, the best thing I can do is to apply the nuts dry to the correct torque and job done. Thanks again. Neil |
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30th Nov 2020 6:10pm |
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| Matt110 Member Since: 29 Jun 2014 Location: UK Posts: 673
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Oh wow don't do that you'll never get em off
No worries. You guys have far bigger nuts than us!!!! What do you do in Civil is there the same torque setting process? |
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30th Nov 2020 6:11pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16931 
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Normal rules don't apply with alloy wheel nuts due to the dreaded corrosion. The thinnest smear of copper grease on the faces that contact the wheel, as well as the areas of the wheel that contact the hub, will potentially safe you hours of strife in the future. If you are in the "grease the nuts" school you will also use modest lubrication on the threads.
I am a mechanical engineer (and have the certificates to prove it) and have been lubricating my wheel nuts for over 40 years without any dramas, which should tell you which side of the fence I sit. However this is a "Marmite" subject which polarises opinion and the only thing that everyone will agree is that we'll never all agree! |
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30th Nov 2020 6:24pm |
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| Bps Member Since: 14 Feb 2016 Location: Lancashire Posts: 785
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Alloy wheels nuts definitely, thin smear don’t cake it on, locking wheel nuts yes again as the locking tools seem to be made of cheese when it comes to undo one that someone accidentally tightened up with a nut runner.
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30th Nov 2020 6:29pm |
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| Slideywindows Member Since: 09 Sep 2016 Location: North Essex Posts: 1283
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As it happens, I've just taken all 4 alloys off my Defender today, to get new tyres fitted.
So come on chaps. I need at least 5 more pages of argument before I can make up my mind on this.  |
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30th Nov 2020 7:05pm |
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| Bluest Member Since: 23 Apr 2016 Location: Lancashire Posts: 3998 
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How's about this to mull over, for use with alloy wheels, consider ceramic grease instead of copper. Non-conductive so less bi-metal corrosion is my theory. Not that I ever had any trouble when I used copper grease, but I read something on here about it which got me worrying so I changed. That's what forums are for
2007 110 TDCi Station Wagon XS |
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30th Nov 2020 7:12pm |
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| Matt110 Member Since: 29 Jun 2014 Location: UK Posts: 673
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....... so why don't normal rules apply? The wheel is still either over torqued or undertorqued until it corrodes. If you then apply worst case engineering scenario to the nut, it'll fail. All you're doing is making it easier to get off when it does eventually corrode. Opinion? Polarised |
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30th Nov 2020 7:13pm |
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| Mossberg Member Since: 29 Feb 2020 Location: Lancs Posts: 552 
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A question to those that know and understand this far more than I do - whilst lubricant on the thread can allow you to put too much strain on the threaded stud, what happens if the thread on both nut and stud have a level of resistance due to corrosion when turning the nut - will this have a consequence opposite to damaging the stud?
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30th Nov 2020 7:18pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 19651
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I’m in the very little camp grease wise.
Considering they are safety critical and torqued for a reason. Greases whilst prevents corrosion also creates some lubrication. Considering they are torqued to a setting to ensure they are tight enough but not over done you don’t want any form of lubrication helping the possibility of loosening over time. So I tend to avoid greasing any torqued fixing unless it’s stainless, if greasing has to happen use very little indeed. I don’t tend to do my own instead is done when she goes in. Spray grease gets used so it’s much thinner and lighter in quantity. There is also the issue where the grease gets contaminated and can create a fine grinding paste too. I am no expert though, I don’t profess to be but as I said I’m in the none to just a little on threads camp. Diesel$ Live$ Matter. ⛽️🛢️👨🔧🧰⚙️ RED, WHITE & BOOST! 🇬🇧 |
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30th Nov 2020 7:33pm |
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| jcw Member Since: 11 Sep 2016 Location: Gloucestershire Posts: 152 
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Light smear of copper grease on the stud & torqued to normal spec. for me, not lost a wheel or sheared a stud although appreciate the torque setting applied may well be slightly higher.
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30th Nov 2020 7:47pm |
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| Retroanaconda Member Since: 04 Jan 2012 Location: Scotland Posts: 2557 
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From the workshop manual, point 7 is relevant:
 Click image to enlarge I’ve always put a very small run of light oil on the thread to stop them rusting so much and giving false torque readings when tightening. |
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30th Nov 2020 8:24pm |
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| v8bob Member Since: 14 Mar 2018 Location: Midlands Posts: 305 
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I don’t know what the strength / rating of wheel studs are, but I would guess they are 10.9 or 12.9.
So, assuming you have M16 the max recommended torque: 10.9s is 354Nm 12.9 is 413Nm So, are you likely to snap them if you use a torque wrench, with or without lubrication? The next thing to look at is could you damage your wheels? Alloys have a flat mating surface for the nut, so you need to look for any crush damage. Not lightly to happen on a genuine Land Rover wheel because they are pretty thick around the holes. Steels, just use the hd rims then you will be fine, but again check for damage around the holes. Hubs, well they are substantial chunks of metal, crush damage, stud pull through - I doubt that. Wheel nuts, Genuine must be at least rated the same as the studs one would think or at least hope. Be careful where you get your parts from! That’s my view |
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30th Nov 2020 8:57pm |
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| ARC99 Member Since: 19 Feb 2013 Location: North Yorkshire Posts: 1831 
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I have the same qualifications but stopped putting the letters after my name. I have always put a extremely thin coat of copper grease on the studs to aid removal for over 50 years. Dealers don't do it but Indie will as they are proper mechanics. Matt100 is correct in what he says but you will not snap the wheel studs as the torque setting so low for the stud size, not having information of the material use at what torque the studs will snap but having seen a very large male jump up and down on a 3 foot bar to tighten his I would say 250flbs is the max. it is more likely that the stud will snap when trying to take the wheel off due to the corrosion. . Don't make old people mad. We don't like being old in the first place, so it doesn't take much to  us off.
Richard |
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30th Nov 2020 9:07pm |
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