chandler said:
Hate to weigh in here but knurled and angry have this right. Because you do it differently doesn’t mean it’s “right” or that you will die. Torque is used but only to get the right amount of clamping force, if something is between the wheel and mating surface or is on the studs it lessens the likelihood of getting the right clamping force. I live in NWOhio so I know all about rust belt living and clean the studs and dab anti seize every couple years.
I never said they were wrong. Being a "Hack" was what I was having fun with. I mean if I am going to be called one I may as well live up the the expectations associated with being a Hack. 
Speaking of memory. I had an old 3/8" drive impact gun and at 100 PSI it would torque my Porsche lugs to exactly 89Ftlbs. Spec if I remeber was 87 Ft/lbs I checked it more than a few times and it was always with in 1 or two lbs. It made just blasting on the lugs really simple. I know another friend that has a regulator in line with his impact and he sets the PSI to get to specific Torque specs for lugs. I have checked it several times and it is again always with in a ft/lb or two. Makes tire changes really simple and fast. Yes it is not perfect as thread pitch and lug diameter probably change things but for the average car lugs it was well with in spec.
I worry more about anti-seizing my centerbore. I have to kick the wheels off my e36 and I hate it.
FC RX7 wheels are the worst. Those will weld them self on the car.
AnthonyGS said:
I’m actually a mechanic that got a degree in engineering. I also spent some years as a nuclear mechanic on a submarine. Crazy enough but muscle memory is an approved torque in cases where things are difficult to access with a big ole torque wrench. If you practice the torque first, you can get pretty close.
My secret go to lube for things like this is colliodal graphite suspended in isopropanol. It’s a dry lube and does prevent rust on wheel studs and bolts. It really excels at preventing galling which is invaluable when dissimilar metals are involved.
https://www.newmantools.com/chemicals/neolube1pds.htm
Stupid nuke mechanic / engineer outta here now. Do it however you like.
Checking on the neolube, it's $78 for a two-ounce bottle with the HazMat shipping charge?? Dang, that stuff sounds scary.
In reply to stan :
GRM method: get some isopropanol from the drug store, grind up pencil lead, mix.
The "real" answer is dry. Period. That's what the OEMs do. So if you apply lube of any kind, the only way to get the proper torque is with a bolt stretch gauge.
I say that because it is just how it's done. I'm not saying that lube = death, I'm simply saying that it is like putting a fuel pressure regulator at the tank instead of on the fuel rail; there is no way to predict what pressure actually makes it to the engine.
Torque values are a representation of bolt stretch and nothing else. It is a function of the stud material, thread pitch, and diameter. It is just a known, close-enough guess that X lb-ft of torques will cause a dry 7/16"-20 bolt to stretch about 0.Y inches for the correct clamping. It really has nothing to do with how much rotational torque you put on the nut, it is simply an easy way to translate a good guess that puts you in the proper stretch range.
If you lube the threads and torque it to the same X torque, you risk significantly overstretching the bolt depending on the lube.
This was the impetus behind TTY torque specs. In the old days you would torque head bolts to X lbft. Depending on the threads, the lube, the washer, etc, 80 lb-ft can represent a much more significant variation in stretch from bolt to bolt since there might be wider variations in the friction seen at the thread/head. Instead, if you torque to 40 lb-ft, there is much less likelihood of that wide variation. Then you finish it with (for instance) 90 degrees of additional rotation. Since the thread pitch is a known quality, it makes a more predictable stretch quantity regardless of the actual rotational torque you put on the fastener. Just like you wouldn't expect head bolts to properly clamp if you install them dry because the spec was engineered for lubed threads, you can't expect lug nuts to clamp properly when installed with lube because the specification was engineered based on a dry installation.
TL;DR.... I won't tell you to lube or not, but I will say that the engineered spec for the lug is based on dry installation. If you lube it, your torque spec is now a completely useless number. In the case of something like head bolts, the spec is designed for lubed installation. With lug nuts, the spec is engineered for dry installation.
Tyler H said:
PS...Lug bolts suck.
I love the lug bolts on my RX-7. Now the LH lug nuts on my REPU surprised me right off the bat when I didn't know it had them, and I snapped one of them trying to "loosen" them with an impact gun.
Page three and no lubed nut jokes?
Personally, I have no idea what my manufacturer's recommendation is, I guess I could ask mom.
He wants his lugs torqued
In reply to stan :
It lasts a really really long time.....
So what is the actual percentage increase in clamping force of lubed versus dry? Are we talking big numbers here or small percentages?
Curtis said:
If you lube the threads and torque it to the same X torque, you risk significantly overstretching the bolt depending on the lube.
Or in the case of lug nuts, the taper in the seat will pinch closed, causing for reduced tension on the stud for a given amount of torque on the nut, as well as a nut that binds when you try to remove it. The horrible part is that when this happens, the hack (yes, if you put unspecified lubricants or antiseize on threads, you may not BE a hack but you are using a hack's skillset) uses this as a justification to keep using various goops on the threads. "See, it's binding up! Gotta add more oil on it! And I gotta tighten it until my elbows pop, 80ft-lb just isn't enough!"
Clean dry threads. If you have rust problems, switch to one-piece acorn style lug nuts. Open-ended lug nuts are the devil, as are acorn nuts that are merely open-ended nuts with a stamped beauty cover pressed on top. (I'm looking at YOU, Chrysler!)
Again, and people wonder why I love lug bolts so much. Even if you're a hamfist who overtorques the hell out of everything, they will still unthread and reinstall easily. Overtorque a taper seat lug nut once, and it's FUBAR.
dean1484 said:
So what is the actual percentage increase in clamping force of lubed versus dry? Are we talking big numbers here or small percentages?
By recollection, 30w engine oil reduces the torque required for a given clamp load by 30%. (So to achieve 100 ft-lb clean/dry threads of "bolt tension" with oil on the threads, you'd torque to 70)
Moly lube reduces the torque by 90%. Ninety percent.
There was a whole chart, but those are the figures that I remember because those are the things commonly available.
I grok why manufacturers specify a torque + angle for everything nowadays. There's zero question. You "torque" it to set the fastener to a baseline, then you set the tension preload with the angle. And if they say engine oil on the threads and the head of the bolt, do THAT. But if they say only the threads, ONLY do the threads, leave the head dry. Hell, ARP recently issued a bulletin about this. And they changed the formula for their fancy installation lube to put some static friction in it.
I have to post this here. Sorry.
https://youtu.be/IhI3DJdjSYQ
In reply to Brett_Murphy :
oldie but a goodie. 
dean1484 said:
So what is the actual percentage increase in clamping force of lubed versus dry? Are we talking big numbers here or small percentages?
Not really the issue. The issue is a potential overtorquing leading to yield failure, resulting in broken studs or bolts; then you could lose a wheel. This is why you should inspect studs and bolts prior to reuse.
Humm I disagreed. Tork of a bolt measures rotational force that translates to clamping force on the wheel. Lubing things makes it such that you need less rotational force to achieve an equal amount of clamping force compared to a dry application. Or look at it this way you will get equal bolt stretch with less rotational force on a lubed bolt. I want to know what the difference is in rotational force between dry and lubed to achieve the same amount of bolt stretch.
make sense?
In reply to AnthonyGS :
By the way you contradict your self there saying it is not an issue but then saying it can lead to over torquing and failure? That is a big issue.
Knurled. said:
Curtis said:
If you lube the threads and torque it to the same X torque, you risk significantly overstretching the bolt depending on the lube.
Or in the case of lug nuts, the taper in the seat will pinch closed, causing for reduced tension on the stud for a given amount of torque on the nut, as well as a nut that binds when you try to remove it. The horrible part is that when this happens, the hack (yes, if you put unspecified lubricants or antiseize on threads, you may not BE a hack but you are using a hack's skillset) uses this as a justification to keep using various goops on the threads. "See, it's binding up! Gotta add more oil on it! And I gotta tighten it until my elbows pop, 80ft-lb just isn't enough!"
Clean dry threads. If you have rust problems, switch to one-piece acorn style lug nuts. Open-ended lug nuts are the devil, as are acorn nuts that are merely open-ended nuts with a stamped beauty cover pressed on top. (I'm looking at YOU, Chrysler!)
Again, and people wonder why I love lug bolts so much. Even if you're a hamfist who overtorques the hell out of everything, they will still unthread and reinstall easily. Overtorque a taper seat lug nut once, and it's FUBAR.
It's weird how many Miata's, including my old track rat, run ARP studs, open-ended aluminum lug nuts, and anti-seize and aren't snapping studs and loosing wheels and crashing all over the place.
It's really, really strange.
I'm throwing the following out there just to add to the mix for fun: What about the whole lubricating an inclined plane issue? I'll be keeping my nut lubricant preferences to myself.
fanfoy
Dork
12/7/18 11:21 a.m.
Let's put some actual numbers on this shall we.
The torque calculation is based on a coefficient of friction K.
T = K F d
Below are some values I picked from the interwebz:
- normal dry: K = 0.2
- nonplated black finish: K = 0.3
- zink-plated: K = 0.2
- slightly lubricated: K = 0.18
- cadmium-plated: K = 0.16
We are talking about a 10% difference between dry and slightly lubricated. What slightly lubricated means is rather unclear.
Unless you actually test out the coefficient of friction for your particular application, this calculation is a rough estimate at best.
Now also take into consideration that most torque wrenched have an inaccuracy of about 20%-25%. Some can have an accuracy of 2%, but they are mucho $$$$$$$.
The point of all this is to point at that this discussion is pointless.
In reply to fanfoy :
I'm used to seeing calibration records of +-3% for torque wrenches.
I'd be pissed if I got one back from CAL and it was more that 5%.
Even my personal less expensive click type wrenches calibrate to around there. Nevermind the tolerance stacking with the lube and error in the wrench.
fanfoy said:
Let's put some actual numbers on this shall we.
The torque calculation is based on a coefficient of friction K.
T = K F d
Below are some values I picked from the interwebz:
- normal dry: K = 0.2
- nonplated black finish: K = 0.3
- zink-plated: K = 0.2
- slightly lubricated: K = 0.18
- cadmium-plated: K = 0.16
We are talking about a 10% difference between dry and slightly lubricated. What slightly lubricated means is rather unclear.
Unless you actually test out the coefficient of friction for your particular application, this calculation is a rough estimate at best.
Now also take into consideration that most torque wrenched have an inaccuracy of about 20%-25%. Some can have an accuracy of 2%, but they are mucho $$$$$$$.
The point of all this is to point at that this discussion is pointless.
That is exactly what I was looking for. Thanks for the education!!!!
Ok so my next question is what is the multiplier for designed failure that is typically used for the design of lug nuts bolts and studs on your average street car? Any car design engineers out there that can comment on this?
