My car 1990 300E 4mat had new Continentals put on at the time of purchase, so I dont really know if the problem pre-existed these tires.
The steering has always vibrated a little at hwy speed...but as it worsened and then became unnacceptible, on this forum's recommendation I sought out a tire place that had the Hunter 9700 GPS. They were sure of the problem being fixed, even got a very fancy computer printout that supposedly confirms the balancing results, but no real improvement. I even .
I found my spare to be in perfect (unused w/ a virgin 15 hole rim, to my surprise) condition, and noticed that the lead weights were factory installed ON BOTH THE INSIDE AND OUTSIDE of the wheel...so out of curiosity i looked under the car and found the newly installed weights only on the outer rim, and none have any inside weights....does this make sense? Not to me..considering the vibration is still there!
So either they're out to lunch and I find a better shop, or I have to find another vibration source...all my shocks are recent, maybe a very slight alignment problem but certainly nothing too obvious.
I drove it today on the hwy w/ the usual vibration. I slipped the car into neutral for a few moments, no difference in feeling even as the engine quieted down to idle.