Snapped of wheel stud at 100lbs.

[gitz676]

This thread is not about my jeep but I would like some advice.
I was rotating tires on my 02 Impala. This is only the third time the wheels have been off. I finished the front and torqued the nuts to 100 lb with nearly new torque wrench. I put the rear wheel on and torqued the nuts up with my impact wrench just till it started rattling. Then I dropped the car and then continued tightening up the nuts with my torque wrench. I seemed to be tightening forever and then I broke off a stud. WTF!! Any idea what went wrong.

 

[mylittlecj5]

Yea. Just about NO vehicle (especially a street car like an Impala) needs the lugs torqued to 100 Lbs.
Most cars are factory rated to around 70-80 Lbs max. Look at your owners manual, or go to a good tire shop to find what your vehicle calls for. Add about 1.5 Lbs. for every inch of the extension used on the wrench.
Never snug lug nuts down with a impact on full pressure. this could loosen or weaken the stud enough that it could fail, like yours did.
Overtightening the lugs can lead to wheel vibration, stud breakage, and warped rotors/drums. I fight with my tire store every time I'm in there to use a torque wrench on my wife's tires, to the point that he asks my wife if "I'm that guy" who likes his wheels torqued when she goes in alone. I just don't understand why an established tire store doesn't just use a torque wrench every time? :rantoff:

 

[Sasquach]

CJ wheel nuts torque to 75ft./lb.