wheel lug nut torque
- Thread starter another Todd
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mechanicx, just to stir the pot, here are two more sites that demonstrate the huge inconsistencies of recommendations for torque reduction using different lubes. Look at the bottom of each chart.
http://www.raskcycle.com/techtip/webdoc14.html
LUBRICANT OR PLATING TORQUE CHANGES
Oil: Reduce torque 15% to 25%
Dry Film (Teflon or moly based): Reduce torque 50%
Dry Wax (Cetyl alcohol): Reduce torque 50%
Chrome plating: No change
Cadmium plating: Reduce torque 25%
Zinc plating: Reduce torque 15%
Baseline torque is calculated for a non-lubricated, un-plated bolt
And.... http://mpi-online.com/technical/torquechart.htm
"Above values are for zinc plated nut and bolt assemblies. Increase torque by 33% if using unplated (dry, unlubricated) nut and bolt assemblies. Decrease torque by 45% if using lubricants (oil, grease, or antisieze lubricants). "
Notice how this one lumps oil,grease, and antiseize together.
http://www.raskcycle.com/techtip/webdoc14.html
LUBRICANT OR PLATING TORQUE CHANGES
Oil: Reduce torque 15% to 25%
Dry Film (Teflon or moly based): Reduce torque 50%
Dry Wax (Cetyl alcohol): Reduce torque 50%
Chrome plating: No change
Cadmium plating: Reduce torque 25%
Zinc plating: Reduce torque 15%
Baseline torque is calculated for a non-lubricated, un-plated bolt
And.... http://mpi-online.com/technical/torquechart.htm
"Above values are for zinc plated nut and bolt assemblies. Increase torque by 33% if using unplated (dry, unlubricated) nut and bolt assemblies. Decrease torque by 45% if using lubricants (oil, grease, or antisieze lubricants). "
Notice how this one lumps oil,grease, and antiseize together.
If you have much experience at all, you have a feel for the springiness of a bolt as you tighten it. When I crank my lug nuts down to 80 pound feet, I can feel the stud springing back a little.
The same thing should tip you off if your clicker is out of calibration.
The same thing should tip you off if your clicker is out of calibration.
That is intersting but I figure new lug threads are usually cadium or zinc plated, so that extra is already figured in. Then the plating may eventually corrode off. If you use oil on the threads that have corroded some, seems like you could then go up to almost full torque. If you use anti-sieze then maybe you should back down about 20% on corrode threads. And looks like it is not a good idea to use anti-seaze or dry film lubricant on non-corroded threads.
I still think that there is a margin of error built in and I think if you torque to specs with dry even somewhat corroded threads the wheel will be tight enough. I don't bother with putting anything on the threads. I agree with Labman if you have developed the feel you can tell when a bolt is tighten right by hand.
It looks like using anti-seaze and not reducing the torque probably at least 20-30% might be over torquing the parts though.
I still think that there is a margin of error built in and I think if you torque to specs with dry even somewhat corroded threads the wheel will be tight enough. I don't bother with putting anything on the threads. I agree with Labman if you have developed the feel you can tell when a bolt is tighten right by hand.
It looks like using anti-seaze and not reducing the torque probably at least 20-30% might be over torquing the parts though.
There is no question you have to be careful if you lube the threads/seat, especially when the tire shop gets a hold of your car. Well-designed hub systems with tight diametrical location of the wheel with a spigot should not suffer in performance with greased threads, or any other part of the joint. However, I would not grease any wheel/hub that that relies on the nuts only for location.
Certainly no more than 80% of dry spec is appropriate and it seems to depend a lot on the speed of tightening. On my latest little car I just tighten them with a 10" wrench by hand, check them later with a torque wrench. 60 lb-ft is the factory spec, go for about 50 wet.
I've worked as an engineer for decades and certainly agree many I've met over the years do not have good practical experience. It takes many years of wrenching in addition to the education to see the full picture.
Certainly no more than 80% of dry spec is appropriate and it seems to depend a lot on the speed of tightening. On my latest little car I just tighten them with a 10" wrench by hand, check them later with a torque wrench. 60 lb-ft is the factory spec, go for about 50 wet.
I've worked as an engineer for decades and certainly agree many I've met over the years do not have good practical experience. It takes many years of wrenching in addition to the education to see the full picture.
I have run the "lube experiment" many times. I spray the threads with a little WD40 or sometimes a drop or two of motor oil, then torque bolts to 85-100 ft-lbs per the manufacturers spec.
Since I usually run dedicated winter tires I have used my Torque wrench to remove them several months later just to check - the value required remains close to 100 ft lbs.
Whats not to like??
I have been doing this ever since I started driving - a 1941 Plymouth - and have never had even one bolt loosen up. Yes, the 41 plymouth was left hand thread on one side (passenger?)
Chrysler thought that would keep them tight somehow!!
The only problem I ever have is tire shops throw them on with their air guns, we twisted off several studs on my sons car the NEXT DAY when we went to recheck them. They were way past 200 ft lbs, and would have been impossible to change on the highway. Firestone-Bridgestone store said no way we did that, but the torque wrench tells no lies. Re torquing them and rechecking later, they stayed near 100.
Since I usually run dedicated winter tires I have used my Torque wrench to remove them several months later just to check - the value required remains close to 100 ft lbs.
Whats not to like??
I have been doing this ever since I started driving - a 1941 Plymouth - and have never had even one bolt loosen up. Yes, the 41 plymouth was left hand thread on one side (passenger?)
Chrysler thought that would keep them tight somehow!!
The only problem I ever have is tire shops throw them on with their air guns, we twisted off several studs on my sons car the NEXT DAY when we went to recheck them. They were way past 200 ft lbs, and would have been impossible to change on the highway. Firestone-Bridgestone store said no way we did that, but the torque wrench tells no lies. Re torquing them and rechecking later, they stayed near 100.
Hostile enviroments , road chemicals, dictate the use antiseize as an viable option to frequent fastener/stud replacement. I like the CAT brand. The pretrip/posttrip inspections have a purpose.
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Long before it needed anything, I pulled the wheels and brake drums off my 02 Cavalier and put everything back with a light coat of antisieze. I usually use cheap Permatex from the auto store.
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