Sheared my lug nuts off!

[bettabruce]

I was driving and heard a terrible noise from my drivers rear tire area.
I looked today and all six of my lug nut studs were sheared off!
Anyone got ideas of a cause?
I didn't know it was possible
And I'm lucky the wheel didn't fall off
Thankful for that

 

[ktmoutfront]

They were lose.

 

[6872xtc]

My experience is that if they get over tightened at any time, then the studs can snap off. They may not fail all at the exact moment, possibly a couple first which can take the others out.