It's been a while since I looked in this part of an engineering
handbook, but here's what I remember. When antiseize or any other
lubricant is used on lug threads, you have to derate the torque you put
on the lug. Here's why: Part of the torque goes into clamping force
along the axis of the lug, and part goes to overcome thread friction.
The thread friction is not very predictable, but it isn't negligible.
When you decrease thread friction with a lubricant, that torque goes
into increased clamping force. Too much will either stretch the lug,
or cause cheaper (cut, as opposed to rolled) threads to crack, which
really will bind up fiercely.
I found that different books gave different fudge factors for antiseize
versus dry threads, but the intersection of them all seemed to coincide
with the lower end of the factory torque range. I've used 70 ft-lb
with antiseize on my Miata for 3 1/2 years now, and never had a problem
with binding. Plus it makes changing tires *much* easier on race day.
My take: The improvement in consistency of clamping force far
outweighs any risk of binding. I do keep an eye on it and renew the
antiseize when it gets grotty, though (about once a year on average).
Craig Blome
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