Sheared off lug studs?

yesterday on my way to school my truck somehow sheared of 4 of the six lug studs on the passanger side on the same side of the tire, they were almost new studs torqued properly, i didnt hit a pothole or anything and was wondering how they possible sheared off

 

What kind of lug nuts? Steel or alloy wheels? Who torqued them?

 

steel nuts, steel wheels, I torqued them to 100 ftlb the studs sheared off completely

 

Isn't stock spec 85lbs?

 

Is your tourqe wrench calibrated correctly? Even 15 lbs over they shouldn't shear off like that.

 

i don't know i used the schools wrench, but its been 650 miles since ive taken the wheel off last

 

maybe they were just slightly loose and wobbled and just snapped them off. just stick new ones in there and keep an eye on it.

 

x2, I would guess they were loose. If they were new rims, they're supposed to be torqued when they're put on, driven a few miles then re-torqued. Not sure how you managed to shear 4 of them off, but something wasn't right, either you hit something hard when off-roading or rock crawling (which you'd probably remember doing) or your torque wasn't correct on those lugs.