Vibration at 70 MPH.

put tires from rear up front and front to rear and see if tires cause a shake also make sure no debris on hub so rim sits flush if no change and still vibration check drive shaft and u joints

Have your Mechanic check the steering tie rod bushings, and linkage. Sometimes it's just an adjustment to the steering box play(located at the end of the steering wheel shaft), - easy to fix.

It's your front tires. They need to be rebalanced.

I am a minor shade tree mechanic here so this is just a guess. It might be a front brake rotor, a break pad caliper that has a sticky hydraulic piston, front wheel bearing, or something else. Look at the pad and rotor wear for it possibly being a break system issue. Not sure, if you do not have a solid front axle look at the inner part of the wheel under the vehicle where the ball mates into the socket for any wet fluids or unusual gunk or build up around the axle and break calipers for a wheel bearing problem. Jack up the front end and make sure you chalk the rear tires, vehicle is in PARK and the steering wheel is unlocked as to where the steering wheel can be turned if needed. After vehicles front tires are off the ground try to pivot the front wheels to point in a different direction left turn or right turn. This can be tried by physically grabbing the tire trying to move the tire to point left or right. If the front tires are able to be pointed in a different direction without the aid of the steering wheel, then it could be a wheel bearing issue or a more serious issue. Hope you can make sense of these instructions, and hope this helps you find and fix any and all existing problems you are having with your vehicle.

i would suspect somewhere in your front end you have a compliance bushing with excessive movement. these cars front ends depend heavily on these style bushings, and as they wear you can start to see tire wear patterns, looseness in steering, and high speed vibration. make sure you have the front end inspected by a shop that is familier with these types of cars. good luck!

Hi:
Since your BMW 540 series is a rear wheel drive car, a common cause of that sort of vibration is often the U joints on your drive shaft. The vibration often only shows up and certain speeds.

It isn't a particularly expensive repair, but is something to have checked out!

ball joints or bent rim. Does it click or thunk when turning? It may be tie rod as well. You can lift it up and try turning wheel by hand and shake it to see how much play there is.
Check the there is a weight on the rim. Every one is supposed to have one.!!!!

if it were the rotors it only happens when braking take in have them turn rotors see what happens good luck

Most likely with this problem is the front tires. The tires maybe " out of balance " or " out of round " causing the vibration at certain speeds.

Front shocks are week