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Old 11-04-2007, 08:48 PM   #22
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Member#: 11218
Join Date: Oct 2001
Chapter/Region: SCIC
Location: Orange, CA
2005 Legacy GT Wagon
99 Miata, 91 Miata turbo


Originally Posted by Patrick Olsen View Post
3?! Yikes! That's not even remotely enough. Based on which engineering guidelines you look at, the recommendations of minimum thread engagement range for a fastener loaded in tension are generally in the 3/4 of the thread size to 1-1/2 the thread size. So for a 12mm wheel stud you're looking at 9mm - 18mm of thread engagement. (I don't think even the stock bits would give 18mm, so that's probably a bit high for our application.) So, at the low end of the range, 9mm divided by the 1.25 thread pitch gives 7.2 turns. There's not a chance in hell I'd trust 3 turns on my lugnuts!!

And hello outside shoulder wear because of 0 camber!
Thanks for the correction. McGard has a similar recommendation: "minimum thread engagement must be equal to the thread diameter of the wheel stud."

So, that would equate to 9.6 turns. I thought 3 sounded pretty small, hence my caps on the MINIMUM part.
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