fuchs lug nuts
 

1981 911sc

anyone know why one lug nut on each wheel is different from the others?

Tx! john

Does the one have a hole in the middle? If so, it was designed to accept lock. Cars came with a lock set which consisted of four locks which would slip over the one nut with a hole in it and lock the wheel to the car. The locks are operated with a key.

no hole. the one lug nut is a larger cylinder with a hex head

Could be a cheaper style of locking lug nut - my car came fitted with these. One of the lug nuts on each wheel is totally round except for a spline at the back. There's a tool that fits into the normal lug nut socket and fits this spline.

"weird" lug nut
 

I just encounered a similar situation. The PO had a locking kug nut on each weel and fortunately had the key in the glove box. I had a flat about two weeks ago and couldn't get the locking lug nut off. It seems whoever put them on used an air impact wrench and really locked those suckers down. The local Firestone shop (5 blocks from my house) charged me $35.00 to take all four locking lug nuts off and I bought replacement lug nuts. I really don't recommend the locking lug nuts unless you are absolutely sure the key mechanism works well, mine didn't and was impossible to torque up enough to get the lug nut loose, a real pain!