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And never apply anti-seize or lubricant to the threads as it will radically throw off your torque wrench values, possibly leading to stretched/broken studs.
The only exception if it the fastener torque values were published as "w/anti-seize" or "w/lube".
And never apply anti-seize or lubricant to the threads as it will radically throw off your torque wrench values, possibly leading to stretched/broken studs.
The only exception if it the fastener torque values were published as "w/anti-seize" or "w/lube".
Some have gotten away with it, just like my mother smoked a pack a day and never suffered for it. But I don't smoke and I don't use anti-seize.
We had a guy in the C6 section who sprayed the studs with WD40 and snapped off two of them before even getting to 100.
100 ft-lbs should be the torque with all lugs accept titanium may have different friction on the steel studs than normal steel nuts. It could be like using a lub or antisieze conpound. If lower friction the holding force will be higher. In fact that could overload the stud and cause thread distortion or even breaking! Doubt that is much of a difference but ask the nut manufacturer. They may have measured the difference and can suggest if you should use a higher or lower value.
That is the problem using torque as a measure of holding power. The thread friction and friction of nut on wheel surface is part of what is being measured. That is why where it is possible, as with connecting rod bolts, the bolt stretch is a far better measure. However for most bolts that measurement is not possible.
Note for the same torque reading, lubing the stud can cause ~3 times the clamping force! For lug nuts, that are designed not to be lubed, could over stress the stud and cause it to break!
PS: Not sure how accurate the 10% of torque is loading the bolt (some say 15%) but this shows one reason to follow the recommendation of using or not using a lub in a particular application. Antisieze is a lub and will alter holding force. The use of a Torque-To-Yield bolt is similar to measuring bolt stretch and avoids most of the friction issue caused inconsistencies.
^^^
Probably a good idea! It is dependent on the antisieze itself. Wonder if the company producing would have a rule of thumb for amount of reduction over dry?
PS: Found this excellent video that quantified the amount of load difference dry versus antisieze. It shows 30% difference so your 25% guess is about right. Note they used very little antisieze.
So how do the folks who use it with 100 ft-lbs get by? They are loading the stud with ~30% more force and since it did not break, it is still below the tensile strength. However with certain antisieze compounds and allowing a small amount to also get on the nut/wheel interface could result in much higher loads. It could exceed the yield strength and possibly the UTS and break!
Another Internet comment was interesting. The fellow attended a seminar of bolt torque versus part loading. They showed a 10/15% difference in load from a dry bolt to just putting their fingers on the bolt. The small amount of oil from their finger made a difference!
Is 100 foot pounds still correct for stock wheels with aftermarket titanium lug nuts?
Years ago I purchased titanium wheel lug bolts for a Porsche, and the bolt manufacture stressed the importance of using a special anti-seize formulated for Ti used with an unlike metal. They also provided a torque chart indicating (based on fastener diameter and thread pitch) how much less to torque the fasteners due to the newly introduced lubricant (anti-seize).
Also, running the Ti fasteners "dry" isn't the answer because the galvanic action between the dissimilar metals will cause galling and seizing over a short amount of time.
IMO, I think it's important enough that you should ask the lug nut manufacturer for their "engineered" recommendation.
^^^
Probably a good idea! It is dependent on the antisieze itself. Wonder if the company producing would have a rule of thumb for amount of reduction over dry?
PS: Found this excellent video that quantified the amount of load difference dry versus antisieze. It shows 30% difference so your 25% guess is about right. Note they used very little antisieze. https://m.youtube.com/watch?v=X3ndeXiZUeM
So how do the folks who use it with 100 ft-lbs get by? They are loading the stud with ~30% more force and since it did not break, it is still below the tensile strength. However with certain antisieze compounds and allowing a small amount to also get on the nut/wheel interface could result in much higher loads. It could exceed the yield strength and possibly the UTS and break!
Another Internet comment was interesting. The fellow attended a seminar of bolt torque versus part loading. They showed a 10/15% difference in load from a dry bolt to just putting their fingers on the bolt. The small amount of oil from their finger made a difference!
Watched the video - great demonstration of the effect of lubrication on friction and resulting bolt load. However, an increase from 71,000 psi to 106,000 psi is a 50% increase in stress not 30% as mentioned.
Watched the video - great demonstration of the effect of lubrication on friction and resulting bolt load. However, an increase from 71,000 psi to 106,000 psi is a 50% increase in stress not 30% as mentioned.
Funny, I looked at and was writing down the stress numbers as well. Decided I would just quote the 30% they did as it was reaching 90% of yield with the antisieze versus 60% of yield without.
However if you look at the raw load numbers they were 5500 pounds load versus 8250. That can be stated 2 ways. 8250-5500 = 2750 difference.
So you can say it is 2750/5500 or 50% more load or
2750/8250 or a dry load is 33% less than a antisieze lubed bolt!
Have to be very careful when comparing things using percentages!
Yep they were correct in calculating as a percentage of the bolts 120,000 psi yield strength as it is was 90% of the that with antisieze versus 60% of yield dry, probably what would be specified! Guess that is the most important as you are only 10% from yielding the bolt using antisieze.
For a grade 8 wheel stud the Ultimate strength is only ~13% higher than the Yield strength so it doesn't take much more to break a stud!
Spending the first half of my career in R&D and second in Marketing & Corp Mgt carefully used numbers to prove the intended point! Since semi-retiring I now use both skills in my Internet business!
Here's a tip. When you buy a used car, or even a new one, check the wheel nut torque. Wheels are often changed right before a sale and mistakes are made.
This is what happens when you -don't- check torque and just assume the seller did it all right! The tire passed me on the freeway, thankfully it didn't hit anyone.
