question: upsize wheels, do I need to change lug/nut?
 

I am not sure which is lug and which is nut, I mean the female one. It's the lug right?
I am upsizing wheels/tires to 17x9 and 17x11.5 now. Do I need to get steel lugs or can I still safely use the black aluminum lugs? Do I need to increase the torque or still 96lb/ft?
Thanks.

You can use without problems the black aluminium lugs with upsized 17" wheels.

http://images3.hiboox.com/images/5207/p4ftwqlt.jpg

cdrik,
Thanks.

Someone, more than one, suggested to use the steel lugs for better safety. Meaning these aluminum are not safe? Agree, disagree? Does anyone has any opinion on this?

It depends on the wheel. There are several different seat configurations used by the various wheel manufacturers. All Porsche oem wheels that I have ever seen use a ball seat, all BBS wheels that I have dealt w/ use a cone shaped seat. The shape of the wheel seat must match the nut and vice versa.

Open ended steel nuts come w/ different seat configs as well but are only needed if the sanctioning body requires them or if the bolts are too long.

torque remains the same regardless of the material. All should be rechecked after driving for a while.

There are LUG NUTS, the 'female' part you are talking about and LUG BOLTS or studs, the things that stick out of the hub that the nuts screw onto.

Aluminum are safe. Some tracks (or organizers) only allow steel, though.

The bolt seat, as Bill said, needs to match the wheel.

While I agree the aluminum nuts are fine for street use you should have one steel one on hand to check one thing, how many threads your lug nut is catching. When using a non-stock wheel or spacers you can easily cut by half the number of threads engaged. For me, unless the steel nut is filled with lug then the lug is too short for that wheel. Of course the opposite can happen also and the lug be too long for the enclosed type nut and in that case all steel open lug nuts are a must.

in conclusion, there 2 things to check:
1- shape of wheel's seat. On this one, I can compare betwen my Fuch's seat and the new wheels, or place the stock nut on the new seat to see if it's perfect matched.
2- thickness of wheel's seat, to make sure the lug come out long enough and lug/nut bite the same length as on Fuch wheel.
Am I correct?

Steel is a good idea, for track use. Extra margin for safety.

Aluminum are fine until you twist the hex off and leave the nut face :mad:

"twist the hex off"
This doesn't have anything to do with wheel/tire size/weight, I assume? Only on usage (open or tighten the bolts) or accident. Am I correct?