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Long ago my little sister called me up– she had gotten a flat tire on the freeway and could not get the lug nuts off. I had to traipse out on a -5 degree snowy day to help her out, and she was right, the lug nuts were on tight and the awful Minnesota salt and consequent rust had not helped either. I actually split a good Craftsman 17mm socket in two in trying to get one of the nuts off.
Ever since then I’ve been putting on a smudge of the silvery (or now coppery) anti-seize compound on the threads before tightening down the lug nut.
But of course this gets you wondering— does this make it easier for the lug nut to loosen itself under normal driving? My somewhat tenuous grasp of friction does not give me any intuitive answer.
To compound this puzzle, I think long ago I read somewhere that if you are torquing down a bolt with a torque wrench, you should lubricate the threads and also under the bolt head, so that you’re not measuring the bolt-head friction, apparently the torque spec wants to assume all the torque is as a result of the threads pulling things tight. So should we put anti-seize on the lug nut to wheel mating surface too? So many puzzles!
Many thanks in advance.
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Actually, you will get more consistent clamping force using lubricant and because there is less friction, more of the torque goes into increasing the clamping force. The clamping force is what is important. With lubricant, it is well documented that significantly less torque is needed to obtain the same clamping force plus the clamping force is more consistent. A Tech with a degree in automotive technology and also an ASE Certified Master Tech in autos and heavy trucks with around 40 years of experience told me that they Also, at his shop, he put anti-seize grease on the threads and lugnuts and torqued the nuts to 20% less than dry and never had a problem with a loose wheel. Actually, according to information I have found, even a greater percentage less may be okay. There should be a torque standard for cars and light trucks that take into account lubrication of the studs and lugnuts.
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