That sucks!! I too had a set of spacers that had the smaller lugs. They got overtorqued and FAILED. I have since replaced them all with a new set of spacers with the larger lugs. I still have the old spacers. I plan on replacing all of the lugs and using them for spares.
Mine failed at 55mph!!! Be glad that yours did not.

Here is the thread I started about mine. FAIL

 

"no, but a piece of billet aluminum is a piece of billet aluminum". TeraFlex spacers are billet steel. If I bought a set of aluminum spacers, I would only buy Spidertrax.

 

And if I wanted billet steel, and didn't already have spidertrax I'd get Teraflex Yeah, I'm suckin up, send me some stickers or something.JJBTW

 

ive had my spidertrax for over 10k.... done some wheeling, round town and highway driving.... no complaints here!

 

I have the Teraflex billit steel no problems

 

Damn! Glad you discovered that and didn't watch one of your tires go rolling past you in the freeway.

BTW, teraflex spacers here

 

Spidertrax here for 30K miles. Glad I didn't go with my instinct and get the cheaper ones like my wife said to do. lol Mine have been flawless.

 

Looks like an incorrect application, 1/2'' X 20 lug nuts would not holld on a 7/16'' stud regardless of the brand.... the guy that installed these on your rig is going to kill someone- thank God it didn't happen in your case.....

 

Also, the spacers in question do not have the hub centric ring that spidertrax and teraflex spacers have. That's going to put more strain on the studs.

 

Sounds like the installers fault, not the spacers. It was whoever installed the spacers fault that they put the wrong lug nuts on it. If the correct lug nuts had been installed in the first place you wouldn't be having a problem.