I recently purchased online a disc of various workshop and training manuals for my 997. They are Porsche manuals. I was surprised to read in an: "After Sales Training - Suspension, Brakes and Alignment" booklet that you should always torque the wheel bolts with the vehicle "off" the ground. I have always done exactly the opposite. I somewhat tighten the bolts and then lower the car before torquing to 96 lbs. This information caused me to go to my owners manual where this procedure is not mentioned. It is likely not that important, but am I the only one doing it wrong all these years.

 

Interesting.

I've always preferred to tighten lugs with the wheels just touching the ground, just enough weight to keep the wheels from spinning. Full weight on the wheels would seem to throw off torquing the bolts uniformly.

Guess I was unknowingly doing something right.

 

I always set the tire on the ground enough so the wheel has grip but I never put all the weight on the wheel until I have it torqued. I'm not sure why I do it that why other than that's the way my dad taught me.

 

on the rears use the parking brake, on the fronts wedge a couple pieces of boards against the tire so it cant turn, or if you have somebody to help, have them press the brakes
to get true torque on the lugs you need to do it off the ground

 

I've been dropping the car to torque my bolts. Hmmm... how much of a difference in torque values have you noticed between the two methods? I'm now wondering how far off I am. Do they recommend any particular method to keep the wheels from free spinning... that is just as important b/c different methods would yield varying torque result... at least that's the theory here anyways. Right?

 

I think the main reason to torque "in air" is to avoid overstressing only a few lugs/studs with the full weight of the car applied without the proper preload in the fasteners. With all 5 torqued the stress is shared properly.

I just lower enough to get friction and then torque away.

 

I guess I need to change my ways as well, since I've always torqued on the ground with all my cars. Never had a problem, but would be interested to know what the variation is between the lug studs from doing them all in the air vs. on the ground. Any engineers out there who have studied the metal stress from one method vs. the other?