Scary/Twitchy feel over 65mph!

Unfortunately not. I've spent a few hundred now on new tyres, wishbones, bushes. Luckily the tracking check was free!

Until I'm more certain what the problem is, I'm putting up with it.

Spoken to a few mechanics and a few Z4 owners, some say it's down to the tyre width, tyre pressures, bad bushes etc.

Having a look on E46 forums, they mention the steering 'guibo' (steering coupler).

I think on every car, each has 1 or more of these issues, always leading to the same effect. This is why it's so difficult to diagnose!

Some have said it's because it was BMWs first attempt at electric steering, but I pulled the fuse out and drove with no assistance from the electric motor and it still happens, so it's definitely more mechanical.
 
Yea I agree, think it is a combination of issues including old bushes and joints.
So far I have replaced tyres, wheels, lolipop bushes, RTAB, rear droplinks and had 2 alignments.
I have ordered a set of Meyle wishbones, front droplinks and track rod assemblies. Not sure when I will find time to fit them but will let you know if I make any improvement.
 
I'd be interested to see how you get on with the track rods, that's the one thing I can think of which would make a difference. It's either this, wheel bearings (doubtful, easy to check) or something in the steering column....or just the width of the tyres & the geometry of the car.
 
Yea im hoping track rods will make a difference as not many seem to say that they have replaced them when having these type of problems. I doubt its the tyres as its exactly the same with my winter tyres and summer tyres which are different sizes. Plus you would think that everyone would have the same issue with the wide tyres
 
carl2990 said:
Unfortunately not. I've spent a few hundred now on new tyres, wishbones, bushes. Luckily the tracking check was free!

Until I'm more certain what the problem is, I'm putting up with it.

Spoken to a few mechanics and a few Z4 owners, some say it's down to the tyre width, tyre pressures, bad bushes etc.

Having a look on E46 forums, they mention the steering 'guibo' (steering coupler).

I think on every car, each has 1 or more of these issues, always leading to the same effect. This is why it's so difficult to diagnose!

Some have said it's because it was BMWs first attempt at electric steering, but I pulled the fuse out and drove with no assistance from the electric motor and it still happens, so it's definitely more mechanical.
Click to expand...
Could I ask that when you had the wheel alignment done did they reset the electronic self centering steering?
 
They didn't actually adjust it when I went, checked it all out in the hunter system, generated the report and showed me everything was within specification. If I remember rightly the rears had slightly different camber but it was miniscule, nothing that would even effect tyre wear never mind steering twitchyness!

Is resetting the self-centred system something which is usually done during an alignment? I need to get it rechecked now I've had the wishbones changed, but thought I'd wait until id had a few more parts swapped to try alleviate the issue before paying for the alignment.
 
adam1985 said:
Yea im hoping track rods will make a difference as not many seem to say that they have replaced them when having these type of problems. I doubt its the tyres as its exactly the same with my winter tyres and summer tyres which are different sizes. Plus you would think that everyone would have the same issue with the wide tyres
Click to expand...

I think it's more the profile than the width sorry. Apparently people with 16" don't seem to get the issue as much as the 18"
 
Took it to an indie today and he had a good look at the front suspension, wheel beearings, steering etc.

The only thing he could identify after a road test was slight play in the steering rack, which felt notchy towards full right lock. It's not too expensive to replace but want to be fairly confident this will fix it! Will keep this thread updated.
 
I had exactly the same problem with my Coupe after removing the run flats. After much advice on here it was cured by a 4 wheel alignment.
And without a doubt it was scary until it was sorted.
It's now 100 times better.
 
I put my winter tyres & wheels at the weekend (Pirelli snow sport at the front and Blizzaks at the back) on BMW alloys, can't remember the code of the rims.

This has stopped 95% of the problem. Can still *just* feel it through the steering, but never pulls the car off-line anymore.

The summer tyres (Goodyear Eagle F1s) where on set of 108 split rims in bad need of a reburb. So in summer I'm going to put the F1s onto my winter alloys and see if that has any effect.

It's definitely not the alignment as this has been checked. Good to hear it solved it on your car :thumbsup: very difficult to diagnose when different issues create the same problem!
 
I had this problem too, changed all bushes, drop links, lollipops etc to meyle HD, multiple alignment checks, finally got rid of it by changing front tyres (despite them looking fine) think the combination of overly sensitive EPS and even slightly mishappen tyres causes quite dramatic handling issues on these cars.
 
So decided to update this thread as I had my new front wishbones, droplinks and track rod assemblies fitted a couple of weeks ago and also a 4 wheel alignment.
I am glad to say that so far I am not getting the wheel wobble/twitch at higher speeds. I haven't been for any long motorway drives, which is where it was most noticable, but have been up to 75 on roads where i could feel it before.
Fingers crossed this has fixed my issue and if it was the track rod assemblies the MOT tester in 2012 (2 years before i got the car) was right and there was play in the inner ball joint. Although not sure why no subsequent tests or services picked this up.

cant wait for the warmer weather now for some more spirited driving :driving:
 
Did have similar at 75-80, left wishbone changed now no problem. Did feel like wheels needed balancing
 
tried all sorts to solve this

new tyres
new track rods
changed for powerflex lolipops/back to Meyle HD
RTAB's
4 wheel alignment (after each of the above chages)

Im almost certain its the electronic power steering - shite design, only way to erradicate it would be to go for an e46 rack or Z4m one if it'll fit... so I've just got used to it :thumbsdown:
 
zedfourthreelitre said:
tried all sorts to solve this

new tyres
new track rods
changed for powerflex lolipops/back to Meyle HD
RTAB's
4 wheel alignment (after each of the above chages)

Im almost certain its the electronic power steering - shite design, only way to erradicate it would be to go for an e46 rack or Z4m one if it'll fit... so I've just got used to it :thumbsdown:
Click to expand...
Working on the conversion !
 
Update from my Zed too...

In order; powerflex bushes fitted, none-RF tyres (eagle asymmetric) fitted, tracking checked (slightly out, nothing to cause this problem), lower control arms changed, steering still 'pulls'. Removed fuse for power steering, still pulls, so unrelated to the electronic power steering.

Now on a new set of wheels with winter tyres, still pulls (same size rims).

Tracking fully aligned by Revolution in Gateshead (would definitely recommend them!). Only difference from stock geometry is could 1.5 camber was the max on the rear (should be 2.5), image attached. :thumbsup:

Myself and multiple mechanics are at a loss! No play in the tie rod ends. Shocks seem in very good condition.

Only thing one mechanic spotted is a very slight notchy feeling present when the car is off the ground, full RH lock, manually turn the right/left wheel a few degrees and you can feel a notchyness in the steering. Doesn't happen with the wheels straight or LH lock. May be wear in the rack and pinion but only at RH lock, not a reason for the steering to feel twitchy on motorways!

So..... Any suggestions welcome :headbang:
 

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Even if you remove the fuse from the power steering it'll still have the electronic rack, I presume installing a hydraulic rack will solve your problem

It defo feels related to the EPS rack to me.
 
I thought removing the fuse would remove any electronic assistance, it's back to just a none power assisted rack and pinion system.
 
carl2990 said:
I thought removing the fuse would remove any electronic assistance, it's back to just a none power assisted rack and pinion system.
Click to expand...

You mentioned previously you are running the PSI indicated on the car door plate ? Is that still the case ?
 
zedfourthreelitre said:
Even if you remove the fuse from the power steering it'll still have the electronic rack, I presume installing a hydraulic rack will solve your problem

It defo feels related to the EPS rack to me.
Click to expand...

No it's a a traditional mechanical rack but with electric assistance, pulling the fuse on the EPS leaves you with an unassisted rack and very heavy steering. This doc explains all - Page 6 re the EPS :thumbsup:

http://www.bmwclub.lv/files/06_E85_Chassis_Dynamics.001.pdf
 
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