I am going to torque my lug nuts to maybe cut down on rotor warping. Do I have to jack each wheel off the ground or can I just do each wheel on the ground? Thanks

 

Just torque them where it sits. After all the side walls of the tires allow free movement. 100 ft lbs it the specified amount.

 

To make sure they're not over-torques, loosen them slightly first and then re-torque to the proper spec.

 

If you do loosen them all then I would jack it up to so that the lug will center themselves in the wheel holes and the weight of the car isn't creating addition weight on the lug area.

 

I will loosen one at a time and retorgue.

 

The proper manner of torquing lug nuts requires several passes to get to 100 ft lbs. You do need to jack up the wheel. Loosen all nuts, and tighten initially to 65 ft lbs or so. Do so in the star pattern going back and forth across the lug nuts. You can really do this with any wrench. Just tighten all with approximately the same force. The second step would go to 85 ft lbs using the star pattern and finally to 100 ft lbs using the star pattern.

That said, no one does it this way. I usually skip the second stage. I tighten the nuts initially firmly, go back over them with the ratchet wrench to good and tight (about 65) and use the torque wrench to 100. What you are trying to avoid is creating a point load at one lug by tightening it too much too soon. You want to tighten them evenly and in steps. I have been doing this for some 45+ years and have never had a warped rotor due to my method. I have had tire stores warp rotors. I check their work now. BTW I live in Ktown, how about you?

 

and don't forget it's a good idea to re-torque your wheels after you drive about 100 miles after you torque them

 

Vinny is correct, remember that all you need do then is use the torque wrench to check the tightness. Do not loosen first. No need to jack up wheel. Even checking requires a star pattern just in case.