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My father (an engineer, but not an auto mechanic) taught me to use a tiny dab of machine grease on the thread (not the rim) of each wheel bolt. This would help against corrosion, and help when loosening the bolt. We've traditionally always switched summer/winter wheels ourselves, on the premise of time and money saved for a simple operation. (Yes, we do use a torque wrench and check the bolts after 100km.)

Online and offline, there seems to be a great deal of argument whether or not to lubricate wheel bolt threads... has this site been able to find a canonical answer? I searched through the tagged questions but didn't find it even mentioned.

If I want to make an informed decision myself, what sorts of pro or contra arguments should I consider?

  • Here is another issue. Is there a difference between using grease on the lug bolts for steel wheels, as opposed to alloy wheels, due to the possibility that alloy wheels may expand more than steel wheels with temperature, thus causing them to be prone to loosening lug nuts? – Tim Shaull Jul 29 '17 at 18:28
  • The loosening issue is that alu wheels are more rigid due to having more material, and therefore, the bolt / nut tension is lost if there's a grain of sand between the hub and the rim and the grain of sand then breaks. That's why it's recommended to check tension after 100 km or so after wheel change. It's not related to temperature. – juhist Jul 29 '17 at 19:52
  • @juhist that recommendation also applies to steel rims. – Torben Gundtofte-Bruun Jul 30 '17 at 7:20
  • I believe most manufacturers dont specify lubing most bolts. lubing bolts can greatly affect the amount of force being applied to the threads and parts. – agent provocateur Sep 14 '17 at 19:17
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Do exactly what the manufacturer of the vehicle states in service information. Why do I say this? The nut rotational friction and bolt clamping force are both affected by the choice of lubricant used or lack thereof. Almost all OEM's specify no lube. This is done for several reasons. Dry results in the most thread rotational friction, a most desirable attribute, this significantly reduces the chances of the lugs backing off and the wheel coming off.

The biggest concern is a wheel coming off at high speed. This is a highly dangerous event because the wheel accelerates ahead of the vehicle as it comes off at great speed and can and has caused deaths.

Of slightly less importance, but still relevant, is that lubricated threads create a higher clamping force for a given torque than specified. This can stretch the studs or bolts, warp the hub flange and/or brake rotor.

I am an Mechanical Engineer and work in the vehicle repair industry. This topic has been a topic of some debate on professional industry forums. Much to the concern of the informed on said forums is that a significant portion of professional technicians refuse to heed the OEM specifications for both lubricants and torque specifications.

  • 3
    Great specific answer. Well written +1 – Pᴀᴜʟsᴛᴇʀ2 Jun 5 '16 at 1:43
  • Except that (I swear I didn't want to open this worm can) wheels won't "come off at high speed" if the clamping force is greater than OEM intentions due to lubricated threads. And it's NOT less importance, it's the absolute crux of it: For head bolts, follow OEM (or aftermarket stud) procedure. For lug nuts, judge the environment and act prudently. Yes, OEM specifies "dry" but they also most likely specify "CLEAN and dry", which is rarely the case. Ultimately, I just would LOVE to dispel the fantasy that greased threads loosen and "back off". Clamping force ends up higher if anything. – SteveRacer Jun 5 '16 at 4:02
  • I used to own a '67 Dodge Dart GT that had left-handed thread lugnuts on one side of the car, based on a paranoia that rotational "devil-wheels-gonna-falloff" forces could be countered going forward by changing thespiral of threads. Generating your ultimate torque with thread galling is absolute folly. Clamping force is what maintains torque. not thread grease. I do agree if the OEM is "clean and dry", then use "clean and dry" since they already did their homework. – SteveRacer Jun 5 '16 at 4:12
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    @SteveRacer The forces acting on bolted wheel joints include, but are not necessarily limited to: Shear, axial, cyclical variation. Then add in variations for, embedding loss, thermal cycling and preload variation due to friction. Then there is the problem of off spec wheels, especially aluminum wheels that lack steel inserts for the nut contact area that make the embedding loss portion very unpredictable. Way to many variables for me to suggest anything other than the OEM requirements or make assumptions about how lubricants might change things. All beyond the scope of this forum. – Fred Wilson Jun 6 '16 at 6:23
  • I would actually say there's a huge safety margin in wheel bolts/nuts. I have tightened wheel nuts accidentally to 120 lb ft, whereas the correct torque was 110 Nm. It is 162.7 Nm, or 48% over the specified torque! I remembered the torque incorrectly and looked at the incorrect scale on the torque wrench. No damage done. I presume accidentally putting grease on the bolts/nuts isn't fatal, especially if you only grease the threads and nothing else. But still, the best way is to follow manufacturer's recommendations. – juhist Jul 27 '17 at 17:28
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I ran a service station for a short stint in Vermont and we always used Permatex anti-seize compound on the lug studs. Most of the time we would also find ourselves wire brushing the threads before removal of the nut and again before applying the anti-seize and reinstalling the lug nut. That was due to the use of salt on the roads of which the state of Vermont used a lot. But in Texas where I currently run a repair shop, we use nothing as it really isn't needed. The biggest problem we see is with tire installers over-tightening the lug nuts with their impact tools, thus stretching the studs and causing the thread galling as previously mentioned on another post. In conclusion; I would say that the use of anti-seize on lug bolts and studs really depends on the environment you are in. But we never experienced a stud failure on any we used grease on and always torqued them to spec.

  • 1
    How do you wire brush the threads before removing the nut? – Glen Yates Jul 27 '17 at 21:40
1

I would be more likely to use an anti-sieze type of grease on studs or bolts that are more prone to rust. I think that the conical mating surfaces of the nut / wheel provide the friction to keep the nuts tight, so lubricated threads helps to preserve the threads with repeated removal, installation and re-torque of the nuts.

  • @FredWilson Agreed, except my point is that the "friction" above is not, nor should be, the largest of many forces to be relied upon to maintain torque. And yet, common perception is that it is, to the point of heated argument. I would also say I agree with OEM (or even SAE) specs, but they aren't just simply "dry". They are most likely CLEAN and dry, which isn't then dealing with age, rust, embedding, or prior thread plastic deformation or galling. I use anti-sieze to avoid galvanic corrosion or just plain rust that ruins any chance of proper retorque without an angle method. – SteveRacer Jun 6 '16 at 16:49
  • @SteveRacer can you please explain what anti-seize actually is? Is it just a can of WD-40? – Torben Gundtofte-Bruun Jun 8 '16 at 17:42
  • 1
    Anything that lubricates is in a way a form of anti-seize, but WD-40 has volatile components and a fairly short lifespan. I was more referring to grease-like compounds that typically have tiny particles of aluminum, copper, graphite, or other high-load bearing chemicals. The use of same probably increases ultimate torque 10-15% on a PROPERLY torqued lugnut. This pales in comparison to the 1/2 inch airgun on full rip... probably 200 lb-ft or more. Which causes plastic deformation of the stud, which REDUCES ultimate torque. The studs are ruined. – SteveRacer Jun 9 '16 at 3:14
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As the owner of a brand new car in salty Vermont, here is my middle-road solution based on reading this, and many similar posts:

The 89 foot-pounds stipulated in my owners manual is very reasonably achievable with my hand-tools. As such, I will follow the clean-and-dry recommendation, when I switch over tires just before and after winter.

However, in the future when I find that it takes more than that to loosen the nuts (110 ft-lbs seems like a good-enough number) then I will accept that there is some seizing that needs to be dealt with, and I'll start applying anti-seize. The goal in this is to make sure that I can actually change a tire on a dark, cold, snowy night with no cell-service and the nearest house over a mile away.

  • If you use alloy wheels, you should also remember to carry a big rubber mallet with you, as the salt may cause the alloy wheel to stick to the hub, even if all nuts are removed. The mallet helps to remove the wheel. – juhist Sep 14 '17 at 13:07
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Just a note: while lubricated threads will create more clamping force for a given torque wrench setting, non-lubricated threads will give a wildly inconsistant clamping.

The good news is that the acceptable torque range for a car's wheels is broad - allowing for road-side tire changes where the 'calibrated' lug wrench is all that is available. And by 'calibrated' I mean "make it good-n-tight".

0

I live in the Maine western mountains. Here there is also a lot of salt brine and sand used on the roads. Recently I was doing some work on the rear of my 2000 Jeep Cherokee. It had been less than a year since the rear wheels were removed. I was very surprised when after removing the lugs I could not remove the wheel. I tried hitting it with a rubber hammer. No luck. The only way I finally got it off was to heat it with a torch. I found it was rusted on. I am putting new brakes and drums on and will clean and prime all bear metal. When I reassemble I will put a coating of grease on all metal parts coming in contact with the wheel.

  • Get some copper paste or copper spray and put that on the hub, it prevents the rim from rusting "onto" the hub as it happened to you. – Torben Gundtofte-Bruun May 13 at 11:35
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I ran a fleet of Leyland buses many years ago. Stud breakage was not uncommon on Leylands. Overtightening causes issues as the stud it taken closer to its tensile strength which makes it more prone to fatigue cracks. It can also make it impossible to change a wheel on the road with hand tools. Undertightening allows the rim to move putting bending stress on the stud putting it closer to fatigue likelihood. Our favourite was to clean the studs allowing them to be checked for cracks. However, they were also checked for physical condition as they had shoulders on them allowing the wheel to be kept away from the hot drum. Sometimes some were worn to different heights causing warping of the rim, again creating an increased tendency to fatigue cracks particularly in the rim. Sometimes we would replace all eight studs. We never changed a single stud, always a full set. We assembled with anti-seize after cleaning the studs of the gummy stuff that seems to accumulate. Although a torque wrench is preferred, it is not always practical. If you do them up with a one metre tube, then check with a torque wrench, you will get the 'feel' of how tight to do them manually with he one metre tube. It is then easy to 'manually' check them whilst out on the road. If the wheel brace kit is on the bus, I can go round and check them anytime. Thus the regularity of checking is as important as the 'accuracy' of checking. Don't forget that running with loose wheel nuts chews the studs out and creates bending forces that are prone to cause fatigue cracks or put the stud closer to an 'end of life 'fatigue crack'. Wheel studs do not last forever.

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