rear 'shimmy' of sorts

[chamilun]

94 530ia

car rides smoothly on interstate and most PRISTINE pavement. however, theres a definite harshness/shake in the rear in most driving 60mph and under. new tires on rear about 2 months ago, and shake was consistent from old tires to new.

any good places to start?

[Mobius]

You say 'shimmy' so it sounds like a side-to-side thing and not up/down...

Side-side is likely a bent wheel. Sorry man. :\

[Robin-535im]

94 530ia

car rides smoothly on interstate and most PRISTINE pavement. however, theres a definite harshness/shake in the rear in most driving 60mph and under. new tires on rear about 2 months ago, and shake was consistent from old tires to new.

any good places to start?

Does the vibration frequency increase with road speed, like you've got a lump in a tire, or is it pretty constant as the speed changes? If it changes with road speed, it's probably related to something in the driveline ( wheels, cv joint, driveshaft, etc.)

You can check if it's your rims by swapping them around. Back to front, swap in the spare, etc. I would think a bad wheel would get worse at higher speed, up to a point.

There are a handful of bushings in the rear whose job it is to keep things steady (subframe, dogbones, trailing arm, diff mount, shock mount) and one of these gone bad could allow it to shimmy. If you can put it up on ramps and get under there with a flashlight you might see some torn rubber parts.

HTH

[chamilun]

ok, not a shimmy, but general 'roughness', and speed independant. smooth as a whistle on the interstate however.

oddly, today, 70 degrees outside, drove much smoother.

very odd

[CrimsonBrian]

I had this problem and I must have taken it back to my mechanic four times before they realized that they had failed to tighted the tire onto the axle all the way, so the tire would wobble on the highway. You might want ot make sure all the tires are torqued on tight.