Steering "Wobble" at 70mph+

G

gordongecko500

Member
Hi All,

Newbie here to Zed ownership but not to BMWs - I need some guidance!

I've just purchased a AUC Z4C Sport with Bridgestone RFTs all round, brand new at the rear and nearly new at the front, 44k miles.

I have experienced the dreaded tramlining, however last night as I was driving home, I experienced a strange oscillating movement in the steering at 70+ mph (particularly round sweeping bends). It's not a vibration but the wheel has a tendancy to swing gently from left to right. I end up fighting with it to keep it straight.

While I was researching before buying I had read that there is an element of aerodynamic lift at the front which causes the steering to be a little vague? I'm not convinced that pressing the sport button gives any benefit.

Is this a normal characteristic of the car or is there likely to be some fault? I'm not sure this is tramlining as I've driven the same route in an E92 with RFTs and it was much more surefooted.

Any advice will be welcome!

(Apologies - I know there are zillions of threads on this but most point toward a fault and I'm not entirely sure that it is.)

Thanks
Paul
 
Hi Paul, welcome to the forum, I am sure someone better qualified than me will give you some clues but, it does sound like runflat tram lining however if you are convinced otherwise I would look at one of two other things, firstly the bushes in the suspension may have excessive play?, or something as simple as tyre pressure?. Either May caused your wandering. I hope you get it sorted quickly. Jon
 
Similar problem when when i testdrove my Z coupe
Obviously ditch the runflat rubber :oops:

Check wheels are balanced correctly ?
Check tyres are wearing even ?
Or as with my ZC when i bought it / grab hold of front wheel each side & shake , if any movement obviously try wheelnuts but if still feeling play then front control arm,s are shot :thumbsup: approx £120 all done with OEM parts
 
csm180 said:
Hi Paul, welcome to the forum, I am sure someone better qualified than me will give you some clues but, it does sound like runflat tram lining however if you are convinced otherwise I would look at one of two other things, firstly the bushes in the suspension may have excessive play?, or something as simple as tyre pressure?. Either May caused your wandering. I hope you get it sorted quickly. Jon
Click to expand...

+1 What he said,

Mine was horrible when I got it, ditched the RFTs, had a 4 wheel alignment and all was cured, a full inspection of the suspension found no problems on mine but tyre pressures are always worth checking particularly on RFTs. Keep us updated :thumbsup:
 
Thanks everyone for the useful advice!

It may well be tram lining - I'm so new to the car it's takes getting used to! Loving it though.

I've read all the threads and debates re the RFTs. As they're brand new I'll probably rack up a few miles on them before replacing them - I'll get the wheel alignment done at the same time then take it from there.

I'll keep you posted on my progress!

(Now I'm hoping it'll brighten up at some point so that I can actually see the car in daylight!)
 
Are you saying you can feel a twitch left to right almost like the electric pas is twitching the wheel ? Giving you a really spooky feeling ?
 
As most say, balancing is a place to start. After that I'd perhaps have a garage check over the suspension/arm bushings because if these are worn you will have slack in the system which can result in some odd outcomes.
 
Sounds like a balancing issue, particularly if it starts at a certain speed.

You've read about run flats. Can't emphasise enough how big an improvement you get by ditching them

Z4 sounds nice, lets see some pics :)


Sent from my iPhone using Tapatalk
 
lotus791 said:
Are you saying you can feel a twitch left to right almost like the electric pas is twitching the wheel ? Giving you a really spooky feeling ?
Click to expand...

Yes!!! Do you have the same experience?

I'll check the balance and get a wheel alignment done and see where I go from there. Changing the RFTs definitely on the agenda. May do that sooner rather than later.

The car has been washed this morning - so pics soon!!
 
had the almost identical issue on my M3, rebalanced at BMW 3 times, went to my Indy tire shop at the other end of the block, fixed perfectly the first time. took the bill to BMW (they sold me the new tires !)
 
I had this and all the balancing and tyre changes did nothing. Turns out the shocks were dead, so not rebounding or absorbing road bumps. At low speed it was just a little stiff and crashy, but got a serious wobble on between 60-80.
 
Personally I don't think it's tyres , try steering angle sensors not sending correct signal to ecu so the electric pas is hunting for centers thus the funny feeling ....Just a hunch !
 
Thanks for all the feedback!

I'm going to get an Indy I trust and is very knowledgeable to take a look over it and give me a diagnosis.

I'll let you know how I get on!
 
Rather than considering random possibilities I'd start simple to complex if you want to avoid wasting time and money,
Tyre pressures
Tyre condition including mishape, uneven wear, bulges on the tread (run your hand round)
Wheel condition, knocks, buckle (jack the car and spin against a fixed reference), whilst it's jacked tug the wheel for movement on the hub (wheel bearing) or sloppy bushes.
ALL FREE SO FAR, then,

Wheel balance.
Proper garage inspection of all suspension components particularly bushes (before an alignment or you may be wasting time/money).
Get a 4 wheel alignment done, preferably hunter. Make sure you discuss weight (fill tank) and the exact suspension spec you have (SE, sport, custom lowered)
Get the indi to check for fault codes, particularly EPS (electric power steering) steering sensor or system low/high voltage which can affect the EPS.

If you still have the issue ditch the RFT's, the above checks and relatively small cost will not have been wasted if you change your tyres, all a good idea to avoid uneven wear on the new rubber.

Good luck :thumbsup:
 
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