Twitchy at speed

[2bmws]

Hi fellas not posted for a while been busy with work.
Wondering been chasing this for a while now when the car gets above 60ish she feels a bit light twitchy and like tramlining. Read on here couple of people have had this problem. Been with the car since I've owned it but just plodded round at 60 but would like to try and get to the bottom of it now.
So since I've had it I've replaced all 4 tyres had the tracking done on a hunters machine. New track rod end new inner tie rods, new bottom arms plus the rear lollipop bushes if that's what they are called lol also changed the front shocks and springs with good second hand ones as my passenger side one was leaking. And anti roll bar drop links although there's no banging or untoward noises underneath drives well the twitch(tramlining) still remains I've also experimented with tyre pressures run them at 29psi as per Google 32 psi as that's what I always run the other bms I've had also tried 36 in rear still the same. Any advice would be appreciated also seen that some have changed the uj on the steering but I can't see any play between the steering and the wheels

 

[Althulas]

I had this but was down to tyres but knackered suspension, tired bushings and linkages would not be helping but changing from a directional patterned tread cured the problem in my case. Have you checked the wheel bearings for play? Have your rear beam bushes been changed?

 

[2bmws]

No mate rear beam bushes haven't been changed, the tyres on car have less than 2000miles on them so wouldn't want to change them for the problem still to be there and bearings passed mot but will jack car up and have a look at that cheers

 

[Althulas]

When you check the rears see if the rear beam is sitting on its bottom plates. Mine where but the change in tyres made the difference but with the knackered components at the rear made the camber worse and didn’t take many miles to prematurely wear them out. Do the symptoms resolve above 60? What tyres did you have fitted?

 

[NZ00Z3]

The original BMW design of the front control arm, rear bushing (lollie pop) has lots of air spaces in it. Once they get a few mile in them the are actually quite loose. I fit the Z3M concentric lollie pop bushing part number 31129069035 (no not fit the eccentric Z3M bushing).

Others fit poly bushings to achieve the same thing.

If that does not sort the problem, then turn your attention to the rear suspension. Change the rear subframe and trailing arm bushings to eliminate any rear end steering.

Original Bushing design

Z3M bushing design, part number 31129069035

 

[Mad2718]

Check your wheel bearings I had this on my 1 series and tightened the wheel bearings and all sorted out now

 

[Eddie Zedder]

If you had the tracking done after changing the tyres but before changing the suspension components I would get it done again.

Personally I would fit new shock absorbers and top mounts, I found that changing the top mounts totally eliminated tramlining on my car.

 

[2bmws]

Ok thanks for advice

 

[AirOps]

If you haven't done the rear subframe bushings I would start there, based on your description of the rear, I think the back of the car has/is settled and that is unloading the front suspension causing the twitching at speed as more air is getting under the front of the car. The M style front control arm bushings will limit movement of control arms improving the steering feel. Polyurethane bushings will provide the best response from the suspension but depending on the hardness (Durometer) they will increase the amount of Noise, Vibration, and Harshness felt in the car.