Mm, there is a mechanical explanation somewhere. This type of problem in my experience, is usually due to non-road-force-balanced tires (usually not required for most but some tires aren't as round as others), non-hub-centric wheels being used when they are needed, damaged wheel, lug nuts with the wrong seat style, unbalanced wheel (i.e. wheel weight fell off), or wheel bearing.

 

no way, you have a problem. these cars are not supposed to shake at 70mph. my car is smooth as butter at 70 and beyond.

try switching your wheels and tires from front to rear. you may have wheels/tires that are not properly balanced. check wheel bearings. check all other front suspension components for wear.

 

BMW's are very sensitive to wheel balance - esp high speed balance - and many shops don't do a great job at that. Any tire imperfections and suspension wear will amplify the problem.

 

+1. My car is smooth over 90mph. Check the wheels and bearings.

 

Agreed, no car should shake at 70 mph.

 

Have your wheels High Speed Balance, not all tire place have this only the one that sells High Performance Wheels and Tires

 

Ive had 3 sets of wheels, 2 suspension set ups, wheel bearings and bushings checked at BMW, and it still shakes at 70. Now once I hit 80... smooth as silk again.

 

I would still have it checked out. It should be smooth at all speeds.

 

I completely agree...