Archived Lug nuts

[bopplumb]

My 2500 4x4 mega cab has problems with the lug nuts. The nut threads are stripping. The studs are fine. I tried to torque them with a Manuel torque wrench and at 135 per the factory "Manuel" the nuts never tighten. Has anyone else had these problems and how do I proceed ?

 

[Bob4x4]

You did not specify what year.Are you sure you have the correct nuts.They have used both 9/16 and 14 mm-very close but no cigar to swap

 

[bopplumb]

2012, factory lugs 22 mm 14mm threads. aluminum wheels. Only place thats worked on it has been dealer till 2 weeks ago. Needed a tire repaired. Needed same fixed again and noticed the issue myself. Lug nuts seem soft.

 

[EDankievitch]

I had the same issue with the 2012 I had. I found that I could not go more that 120 Ft/lbs or I would strip the lugs I think the manual has the tourque for the older 9/16" studs and the metric ones can't take the tourque. I do not go over 120Ft/lbs on my 2013. for that same reason.

 

[MLee]

I would think that torque is for a steel wheel. Aluminum usually is lower, Or am I off base?

 

[Freebore]

The torque specs related to steel vs aluminum come down to the material the stud and nut are made from. In this case they are both steel. If the material of one or the other is aluminum it would reduce the torque, usually by about 50%.

What you should beware of is to NOT lubricate the threads. Torque specs for these studs are based on dry threads and if you do lubricate them you can overdo it. I knew something was wrong on mine as I attempted to torque up to the 135-140 lbf-ft but I had used antisieze and I knew if I pushed it I would strip the threads. I cleaned and dried all the studs and retorqued to 130 lbf-ft and it worked well. I found the factory service manual indicates pretty clearly that the studs are not to be lubricated, I should have looked there first.

 

[Cosmo]

Yeah you're never supposed to lubricate the studs because it alters the friction and therefore it affects the torque required to properly tighten the nuts. I know that I've worked on a bunch of cars from the rust belt and they tend to lube the studs up there.

 

[MattandLana]

Hey I'm a complete newbie and have no opinion on oiling, but I notice that in the TDR extracts of Kevin Cameron's articles ("Torqued Off", Issue 20), he said to oil the threads.

 

[EDankievitch]

Up here in the RUST BELT I have used grease and oil and never sieze on my studs. When Ram went to the Metric Stud something changed quality of metal in the nuts or the studs because they can not take the torque that the manual says wet or dry. Dry they will gall up wet they will strip. I now Torque to 120 Ft/lbs and have no issues. Wheels don't loosen up, I have checked after many miles as one should always do.

 

[JR]

Hey I'm a complete newbie and have no opinion on oiling, but I notice that in the TDR extracts of Kevin Cameron's articles ("Torqued Off", Issue 20), he said to oil the threads.

It depends on the material and thread pitch, whatever you are working on should specify wet or dry torque. Using antisieze can affect torque ratings by up to 30% so if one chooses to use it they must use caution when tightening.

Right or wrong I have always antisiezed my studs and every other bolt on a vehicle as well that is subjected to corrosion. To not do so around here results in a lot of extra work next time around. In extreme cases I've seen the threads on wheel studs come off with the lugnut because the only way to get it off was with 450ft lbs of persuasion. I just grease them lightly and decrease the torque accordingly.

 

[MLee]

The Tire stores say they MUST torque to the manufactures requirements per the manual. On mine thats 150#. I requested 125 and thats when they told me that they have to per the law. did not say lubed or not.
What is the risk of using some lube on the threads? will the come lose? I have seen on OTR trucks they have a lug indicator that shows when the lugs starts to move.

 

[seafish]

The Tire stores say they MUST torque to the manufactures requirements per the manual. On mine thats 150#. I requested 125 and thats when they told me that they have to per the law. did not say lubed or not.
What is the risk of using some lube on the threads? will the come lose? I have seen on OTR trucks they have a lug indicator that shows when the lugs starts to move.

While a DROP or two of oil likely won't hurt anything, lug nut specs are generally given for DRY torque. Wet torque values can vary from dry values by 25% or even 50% more depending on the coeffcient of friction of the lubricant used, so the basic risk of lubing the lug studs or nuts is then OVER torquing the lugnut with the potentially resulting thread or lug failure.

 

[MattandLana]

What is the risk of using some lube on the threads? will the come lose?.

It's not about the nuts coming loose, it's about getting the right tension on the bolt. What we really care about is how much clamping force is applied to the joint in question. This clamping force comes from the bolt (here the stud) being stretched a little bit. Visualise the bolt as an incredibly powerful spring. We usually can't measure how much the bolt is stretching, so we use a proxy measure. That is, we measure how much twisting force is being applied to the nut (i.e. torque), because that correlates to how much 'pull' the nut is putting on the bolt. The manufacturer already figured out the conversion for us - they want the bolt to stretch 'x' amount, so they figured out we need 'y' twisting force on the nut.

But when we apply effort (torque) to the end of the spanner, only part of that effort goes into stretching the bolt to provide the clamping force. Some of the remainder goes into overcoming friction between the nut and the bolt (and some goes elsewhere, e.g. into deforming the nut slightly, some into heat, etc). So for a given amount of torque, the amount of actual bolt-stretching (which we care about) will depend on how much energy is being absorbed by friction. Lubricate means less friction means, for a given amount of effort being applied to the spanner, more stretching force applied to the bolt.

The problem is that too much force on the bolt can result in it being "overstretched" so it loses its springiness and hence loses its clamping force, or worse (and we usually only notice when this happens) the bolt shears or the thread strips.

Hence, we need to know whether the manufacturer expected us to oil the threads, when they told us what torque to apply. If they did, and we don't oil them, then we won't be applying enough stretch to the bolt because we'll be 'wasting' too much of our twisting effort in friction. Conversely, if they did not expect us to lube the threads, then if we do so and then apply the specified torque we'll actually be overtightening the bolt, because the manufacturer assumed we'd be losing more effort along the way through friction.

So the million dollar question is what was the manufacturer expecting!! This I can't say for sure, but Kevin Cameron is an expert, I believe, and he says light oiling, partly to overcome dirt, corrosion, existing deformation from prior tightening, etc.

 

[Kirwin]

The owners manual provides the answer for dually 2 piece nuts. It states to put a drop or 2 of oil on the joint between the nut and washer. Now understand that this is different than the SRW trucks that use the wheel studs to center the wheel vice the hub centered dually wheels. Ken Irwin