[onebadmofo]

I looked and I can't find anything in the search.
Here's the problem:
2007 335i e92 with 52k miles. On a smooth surface the car behaves just fine.
BUT
If the road has "grooves" or "tracks" from, say, semis and buses (kinda like this) car becomes VERY unstable. It kicks side to side, the steering is unpredictable and it's simply scary to drive like that.
If the road is concrete with grooves (like this, like some highways in and around NYC) the car "shifts" side to side once a second or so. Pretty scary too. Especially when you're making a turn at 60mph and feel how the whole car wandering side to side as you're making a turn

Yes my tire setup is out of whack. I have Kumho ECSTAS in the front and no-name tires in the backs. I don't have $ to replace them with RFT as of now so have to use them for now. Would that be the problem? I was recently changing oil and checked front end suspension since both wheels were off the ground. There's no play in any components.

[boymonkey]

Change your tires to the same make and speed rating. They don't have to be RFTs, just need to be the same.

I think a little bit of side-to-side shifting is normal, as I've experienced it in all of the cars I've been in, but a lot of shifting or feeling out of control is not normal.

[BMW-NC]

uhm.... I would blame the grooves..... and your softer non rft tires....

[IancoleTX]

Pretty sure the only thing that would help that is running road slicks man.

[cb1111]

Tramlining is a tire issue. Your mismatched rubber is the cause.

[335BBS]

Cars with sport suspension and low profile tires ALL do this when you get in tracks or grooves on the road. Always have and always will.

[Oulixes]

What you've described is normal for the tire setup you run. The car will tramline to a degree even with OEM tires on it. Motorcycles are even worse.

[galahad05]

You could take it to a shop and have them remove some of the camber from your suspension geometry. This would reduce tramlining (what you're seeing). However, it would also (slightly) decrease cornering grip and normal high-speed stability.

[tony20009]

My car did that with RFT all around. It's just physics. I just try to put all the wheels in or out of the "groove."

[Maestro]

Actually mine did it with the RFT when they were worn, the RFT do not wear evenly so they are really bad on less than perfect road surfaces. When I first started noticing the tacking issue I figure it was the tires since my winter tires did not have much of an issue until recently. Here is the other thing, alignment. If the tires are not right and the alignment could be out and both together will cause this problem.

I just replace my RFT with Conti Extreme DW and had them check the alignment as well it was was way out of whack, both front and rear. The shop said and I believe them, BMW is very sensitive to worn tires which in turn whacks the alignment and they suggest having it checked at least yearly. I could not believe how out whack the alignment was I have owned a number of cars and either never aligned them since they were not out or just had minor adjustments.

Anyway, since replacing the tires with 4 new and getting it back in alignment I am no longer having the tracking problem you described.

[ctuna]

RFT or not some high performance tires are more subject to tram lining than others. Also because high performance tires have more grip they are more subject to this in general.