[NRudy]

Im curious to wether anyone else has experienced this.

When driving my car on smooth roads it drives perfectly no vibrations or shakings or anything.

However when driving around streets with less than perfect surfaces or ones with any groves, or even road markings it seems my steering tries to follow the line and can pull quite abruptly in either direction.

Any idea what can cause this?

[pmmcbl]

So on perfect roads the car doesn't pull at all to left or right? The car should at least follow the camber which is left. If that's the case then I wouldn't worry about it. Around town and bad surface it's normal especially if you have an m sport.

[NRudy]

On smooth roads its fine, it does generally follow the camber left but it doesnt pull either way unless there is something on the road.

It isnt an M Sport, its a SE running 18" run flats.

[djgandy]

Mileage? Probably some part of the front suspension worn out a little. Control arms or similar. All the rubber bushes lose their stiffness and the road tells the car where to go over time.

[achu]

tramlining... usually caused by either toe (check the cars alignment) or tyres - i know some pirellis do it...

[old grey steve]

As I'd say has even said above could be anything, from tyre's to worn lower tension struts.

On smooth roads as you say the car seems to steer true, but tough ground will change things.

Firstly your 335i will have MSport spec suspension even if it's an SE, though its nothing to write home about. Start with tyre's if they've worn down say to 4mm or a tad lower even on 18's their behaviour will change, even more do iif the tyre are feathered on their inner or outer edges (again quite common) feathering is where the tyre starts to deform slightly the tread blocks wear and they'll be a small but noticeable step in the tread blocks (if you were to have the car in the air and rotate each wheel-standing behind each wheel remaining perfectly still if the tyre's feathered you'll see the steps in the deformed tread) it is again fairly common usual suspects are slight under inflation that put more stress if that's the right word on the outer/inner tyre section the centres if under inflated usually have mote tread if your tyre's shown these symptoms then it's a start.

Other contributory factors may centre around the front tension struts(Swann neck arm ball joint facing downwards) and the lower rear wishbone (Straight arm balljoint facing upwards) the tension strut can be felt if you tap the foot brake and you feel a jolt for instance (as your road wheels will be moving forward and back ward as loads applied for instance) if this is the case then it'll also lead to a lose front end and possible tyre wear due to the arms basically moving. The front end will also feel a wee bit unstable, wishbones seem to when they wear promote more of the above but also a tad more of a nervousness which again could be where your coming from, you'll be constantly making oh so slight steering inputs which again you'd class as tramlining.

So look at your tyre's check what they look like turn the fronts lock to lock (if unsure take a couple of photos say with the wheel on lock so that you can see both tyre's full tread width) post the pics then at least visually we can see what these look like.

Suspension wise more difficult of course but to a degree BMW's have always been a bit pointy but if it's too severe as said checks those arms out if you're unsure get them looked at carefully

[un1eash]

My old Z4 on Bridgestone runflats would do the same, would tramline all over the place.

[bhurd320]

Glad i looked here as the thing steve says above about the tyres being under inflated and last 4mm of tread is possibly what i have as the outer edges on the run flat potenza tyres is what I have, and it tends to follow the road slightly, they near to needing replacement but not sure if to junk the runflats but want grip and decent mileage and dont know what to run next

[Bigivo1]

Same thing was happening to mine. I had all four wheels aligned and it turns out the rear ones were miles out. It's much better now.

To be honest it was quite scary before I had it sorted, especially on the motorway. The car would seem to steer one way then the next.