Damn lugs.

[Blue 92]

It certainly looks like that crack was growing for a while before it finally failed when you were tightening. Is there a chance you were driving around with some loose lugs? If you think you might have been I'd think about changing them all out when you replace that one.

 

[Blue 92]

If you happen to get the other piece out without damaging the fracture face and feel like it please post a picture of it. Most of the time a threaded part fails where the nut is starting to load up the threads (usually the first engaged thread) or where the thread transitions to solid shank. Yours did not crack at the nut/thread interface so it would be interesting (at least to me) to see what was happening at the other end.

 

[alwaysFlOoReD]

The pic above shows the lug partly extracted from original, i unscrewed it... And looking at the newly bought lug it did break where the thread transitions to the shank. I will get a pic once i do the swap.

 

[rusty ol ranger]

The pic above shows the lug partly extracted from original, i unscrewed it... And looking at the newly bought lug it did break where the thread transitions to the shank. I will get a pic once i do the swap.

You got 5 other ones.