One thing I realized when trying to track down vibration issues on my 964 was that it had the factory equipped locking lugs on it. The lug nuts plus the locks weigh about 1 ounce more than the standard lug nuts do. Even though they are closer to the center than wheel weights are, it seems logical that having any "unbalance" on the wheel isn't going to help with vibrations and since the wheels are balanced without any lugs on them they will be 1 ounce out of balance once mounted.

I have read on other boards of people eventually tracking down vibration problems to locking lugs but don't think this has been discussed here. I wonder how many of you are still using the factory locking lugs and if so, have you had any issues with vibrations that were not solved? This could also cause intermittent problems because when the two locks on one axle are 180 degrees from one another they could cancel each other out but when they are "in sync" they could cause greater vibration, so, going through a curve you might not have vibration at the beginning but develop it as the wheels turn at different rates and the orientation of the lugs changes.

I removed the locks themselves (which comprise about 75% of the difference in weight) and drove the car yesterday on the highway and amazingly it did feel smoother, though I still have my faulty tires on it so it is impossible to tell. I had planned on ditching the locks anyway because they are more trouble than they are worth, but this has made me even more anxious to do it and I have ordered 4 "standard" nuts to replace the locking nuts on my wheels.

And to further complicate things I just read in Bentley's technical data book there is procedure for mounting the wheel such that the locking lug is supposed to be put on the painted stud and that is supposed to be opposite the tire valve...hmmm...I would bet this wasn't done on my car.

 

if you are worried about it put it on the lug with the red top. But in my case only 3 wheels have a red top lug.

 

Actually, I now consulted the owner's manual for my car which is very clear. It is a slightly different procedure than the Bentley manual because these wheels are not the same as those shown in Bentley in that my tire valves line up with a hole, they are not opposite a hole on the other side of the wheel.

For my car and wheels the process is to line the painted stud up with the tire valve and put the locking lug on that stud. Of course 95% of the people who mount wheels on these cars are probably ignorant of this (as I was before today) but I am certain they have incorporated a counter weight in the hub to account for the extra weight of the locking lug. Of course they did and I should have known this after owning German cars for more than 30 years there is always a special procedure unlike any other car for a simple task and a damn good reason why they insist on it. I have now mounted the wheels correctly, per the owner's manual. Of course each one was wrong.

I have said it before and will say it again...these cars are made for people who read their owner's manuals (or bring them to the dealer, who, probably follows the correct procedure). Now I have to clean up the locks and replace them and test drive it to see if it made any difference.