Vibration at 65 mph. What the...?

[Unregistered]

My 1994 530i vibrates, sometimes, at about 65-70 MPH. Sometimes it happens in bursts, and it feels as though I am driving over corrogated pavement. If I floor it, it gets through the rough patch. Wheels are aligned, tires are all the same, mechanic is stumped. Car has about 100K miles. Any ideas?

[1992 BMW 535i]

Ball joint?

[Jeff N.]

Thrust & control arm bushings or wheel balance. See www.bmwe34.net for great info on thrust arms.

[632 Regal]

COmmon problem with these cars is the dreaded shimmy, follow Jeffs link for more information. Usually thrust arms cause a shimmy between 55-60 mph and sometimes more pronounced during braking. You say its happening 65-70, which leads me to think that you more likly have an out of round tire or 2, that on top of worn thrust arms could also be whats up. You can check the tires yourself by jacking the front tire off the ground and spinning it and watching for out of round but it is easier on a machine.