Over Torqued Wheels?

[Country Campers]

Jlawles2

Don't tell anyone but I use never seize as well. Way back in the day I was putting wheels on our shop truck at my father in laws garage, truck garage off of the interstate which he had for years, anyhow started to put 1 lug nut on and out of the blue here he comes yelling at me to put anti seize on that, said "if you ever had to pull a rusted lug nut off on the highway in the middle of winter you will appreciate that", words I live by today and I hear his voice every time I do it.

Brian

[Scott'n'Wendy]

I'll just say you need to understand the lubricity of the lubricant you use on stud threads and adjust torque accordingly. The torque supplied by manufacturers is dry torque. Wet torque will be quite different. Not sure if anti-seize is considered a lubricant? If it is considered like graphite..instead of 110 foot-pounds you should be going to 50-60 foot-pounds.

I learned the difference by snapping a stud on my 1 ton truck. So I do it dry from now on.

[TedS]

Anti-sieze is a lubricant.

[Jkwilson]

I was taught that you can’t check torque on a lug that doesn’t move, and the only proper way to check the torque on a previously installed lug is to loosen it slightly and then re-tighten it with the torque wrench.

There are two different frictional forces between materials: Static and dynamic. The classic demonstration is to place a box on a board. Raise the board until the box begins to slide and then lower it some and the box will continue to slide. Same thing happens when walking on a slick surface. Once a foot breaks loose, you can’t stop it.

Same thing applies with lugs. It will take more torque to start a nut turning than it does to turn a moving nut.

The key is that you aren’t setting the torque, but the clamping force or the amount the bolt is stretched. Torque is just an easy way to get it right without more complicated measurements.

Anti-seize is an incredibly bad idea unless you have adjusted torque specs. Wet bolts stretch too much when tightened and it can result in permanent over-elongation of the bolt. So the next time you tighten it, you have to stretch it even further to meet the torque spec. The bolt loses strength as it becomes work hardened.

[Cate&Rob]

Lubricated wheel lug threads is not what the torque spec refers to. See linked reference for the difference in torque lubricated vs dry to achieve the same bolt stretch.
https://www.engineeringtoolbox.com/t...%20and%20break.

Lug nut torque typically has a range. I tighten to the lower end of the range (in steps) and 50 miles later tighten to the upper end of the range . . . expecting the nuts to move a little at the slightly higher torque.

Rob

[TedS]

Jkwilson I have to respond to your statement that bolts lose strength through work-hardening. Work-hardening increases strength, but reduces ductility. It takes less stretch with lower ductility to reach a breaking point. The studs or bolts don't take as much stretching to break. The yield strength is increased and is closer to the ultimate strength with less ductility due to work-hardening. In manufacturing, annealing is used to reduce the strength increase due to work-hardening. Work-hardening as opposed to heattreating is used to increase the strength of non-heattreatable metals.

[Jkwilson]

Jkwilson I have to respond to your statement that bolts lose strength through work-hardening. Work-hardening increases strength, but reduces ductility. It takes less stretch with lower ductility to reach a breaking point. The studs or bolts don't take as much stretching to break. The yield strength is increased and is closer to the ultimate strength with less ductility due to work-hardening. In manufacturing, annealing is used to reduce the strength increase due to work-hardening. Work-hardening as opposed to heattreating is used to increase the strength of non-heattreatable metals.

Probably the wrong term, at least technically, but it does render the bolts more likely to break in service. I presume the loss of ductility might change the clamping force applied at a given torque, and the deformed threads may also change the force at a given torque. My hunch is that the effect of over torquing is that your lugs will be under tightened even though torque tests correct on future tightenings both from the loss of ductility and the change in thread pitch from stretching.

[Jlawles2]

Loss of ductility will occur when you reach the Yield point of the stud. Someone else may have more information, but you will know when you hit that point normally.

If I pull out my little black book of reference, a SAE J429 Grade 8 or 8.2 bolt - 1/2" 20 TPI calls for 120 ft*lb dry torque producing 14,400 lbs of clamping force. Bolt proof strength is 120,000 psi, net area of a 1/2" bolt using minor diameter is 0.19 in^2 results in force of 22,307 lb. This is approx 85-95% of the force require to permanently deform the bolt. Note these numbers are for standard flat faced bolts and nuts not the conical ones like lug nuts.

Torquing the bolt to the provided value during it's life or slightly over (5%) should not create issues with strain hardening.

Google search "proof load of bolts" and "conical nut clamping force" for more information than your brain is probably willing to ingest.

[Kathy&Jim_Imagine]

WOW! This is getting interesting - LOL -

[Yoda]

I'll pull one and inspect it. Unfortunately, I don't have a spare to test it. If I see anything amiss with the threads, I'll let you know.

Jim

My turn to get you to spend some more money. I replaced my 2 piece lug nuts with McGard brand solid ones (heavy chrome plated). They are holding up well.
https://mcgard.com/ Best price I found was Zoro using a coupon, but Auto Zone may stock them - next lowest price. Mine were 1/2 by 20, but yours look to be 9/16"per your chart.