There is a slight problem with tramlining and Active Steering, and this is probably my only complaint about Active Steering on our 325i.

If you hold the steering wheel firm and resist the tendency for the low-profile tires to tramline, the Active Steering also compensates for the uneven road surface. So it's kind of doing double duty, so it can be very creepy driving on uneven road surfaces. Sometimes the steering wheel will want to tug hard left/right, or the vehicle will veer left/right by itself although you have no actual steering input.

do you have the bridgestones ? I asked my dealer to swap out these #@$^#%#$ tires for Michelin's....makes a world of difference.

whoah... how's that, FREE???
I wanted michelins from the start and was told I get what ever factory puts on and there is no choice... Although no tramlining or at least after extremely wide ones on my sporty e46 i dont feel it at all.

it was part of the deal. I said no bridgestones and if car comes in with them (which it did) they would need to put michelins...if you pay this type of money for a vehicle - it should come with safe tires. I think the bridgestones are unsafe. I had the infamous recall with my ford, and even a TSB recall with my 330i where they replaced the bridgestones after 16K miles with continentals due to cupping and hydroplaning. the continentials are significantly safer and more comfortable on 330 as are the michelins versus bridgestones on the X5. I'd be curious if BMW exports the X5 with bridgestones for the German market or do they use Michelins?

I have got mine with Continental run flats (cant wait to replace them to normal ones).

Anyone please explain what does "tramlining" mean?

TIA

lol, beat me to it :)
the most descriptive information on internet i have seen so far...