X3 swaying problem
 

For some reason I've been having this swaying problem on the freeway while going about 65+. I had an alignment done but the problem still hasn't resolved itself. I’m wondering if anyone might have a theory or a suspension part I should investigate or have investigated.

Do you mean tramlining, where the wheels track and pull in a direction over pavement cracks or uneven pavement? This is a natural consequence of lower-profile tires but I don't know what your expectations are or how serious it is

Tire condition (tread wear, wear patterns, etc)
Tire pressure, specifically the front/rear bias
Front suspension wear items (bushings, links, etc)

Tires are in perfect condition. They have been rebalanced, they were off. Tire pressure has been maintained at 35/41 based on the sticker. Alignment has been done prior to all.

I’m going to have the suspension guy look at it again and make sure the alignment is still good. I'll have him look at the bushings and links, and the rear end sways and upper control arms.

I've had this problem for a while, and it's bothering me. It feels like I’m driving in extreme wind sometimes. Pushing me back and forth. I remember I had this problem on my mini cooper and put on larger front and rear sway bars and it corrected the issue. Along with adjustable rear camber links.

does it feel that the "butt" is not stable? could be rear subframe bushings - at least that's what it was for E53 with similar symptoms...

Yeah it seems like the rear is swaying a bit. The front seems to be fine. You think its the rear bushings? Is there a way I can tell by looking?

on E53 there are 4 tubular support things, one set aft of the rear wheel, the other set is rear of the rear wheel... when you look through the wheel well into those tubes, you will see that they are "filled" with bushing(s)... those are rubber bushings, and sometimes you can just see rubber crumbling out of the tubes, sometimes you see the rubber is half gone or otherwise being "sick"... before replacing them with OE bushings, check to see if PowerFlex makes bushings for your car...

That is for E53, not sure about your ride...

Up to 4 passengers (which is a reasonable load in an X3) the manual calls for 32 psi/35 psi front/rear. The 35/41 is for maximum GVW. If you are travelling loaded to the gunwales, then I would expect it to not be as planted, due to the shock absorbers. If you are not running with more than 4 people on board most of the time, try 32/35 and see if it feels any different. At the very least, drop the rear tire pressure so that it is closer to the fronts. Lifting the rear by overinflating changes the alignment settings.

Worth trying before starting to change out suspension parts.