Twitchy steering 35is - Update now FIXED!

[jelmok]

Hey all,

I an new to the forum and been spending a long time lurking around - some really great information on here. I recently traded in my Z4M Coupe and bought a nearly new 35is. I loved my M, but needed something a bit more useable day to day, and I often felt like I finished a journey having been beaten up by it! I knew the 35is would be a bit of a compromise, and for the most part I am very happy with it, but I have noticed that when driving at motorway speeds that I am constantly having to make small corrections to the steering. It doesn't so much as pull to either side, just isn't quite happy running straight - like it's 'twitchy'. Seems to do it irrespective of whether the car is in normal, sport or sport +. I didn't notice this on any of the test drives, but then I didn't spend a lot of time on the motorway at the time. Did a forum search, and I saw a lot of comments about the E85's doing this, and people blaming the run-flats e.t.c, and talking about tram lining but haven't seen much about this on the E89 forum.

I just wondered has anyone else experienced this, and what did you do to eliminate it (if indeed it can be)?

Thanks in advance and look forward to contributing what I can to the forum.

Cheers,

John.

[metal licker]

Hi and welcome
Havent had that problem myself but i'm on 17 " rft and think the 35i has a different suspension set up

[JDM]

This is more than likely the characteristics of the RFT's. Obviously your M didn't have them. Have to say though that I haven't noticed the problem with my E89 and that's on RFT's.

[kevinmarkwhite]

This probably not relevant cos its not an E89, but I used to have an E90 3 Series with run flats and that tramlined quite a bit. When the time came, I replaced the tyres - with the same tyre, run flat etc and the tram lining stopped!

Didn't make sense, cos they were the same make/model of run flats!

Prior to that I had an E46 without run flats and that didn't tramline. Then after the E90 I;ve had another E46 with non run flats...and that did tramline!

Not sure what my experiences show...probably nothing, but thought I'd chip in.

[Nickm]

If you're close to London, you're welcome to come and try my car out if it helps mate

[Maniac]

The 35is has unique steering in the e89 range so only another is owner can really comment however I would strongly suggest getting the front tracking checked at least as this will be an obvious place to start.

[Z4andy]

My 35iS is rock solid at speed and runs true and straight.

I did however drive a new 5 series that constantly needed correction of the straight ahead positon on the motorway.

Very annoying trait but my iS does not suffer from anything like that.

Just as a matter of interest. Does the car steering firm up ok in sport and sport+ modes?

[jelmok]

Thanks for all the replies everyone. From what I have been reading of similar complaints on the E85 Z4, a lot of it has been blamed on the run flats. Having read a few online reviews of the Potenza's that my car is fitted with, there seem to be a lot of people saying it's not a great tyre and that tram lining is a problem with it.

However, given that so far no-one else on here has had this problem, makes me wonder if there is a problem with the car? Can I ask are all your cars fitted with these Bridgestone Potenza tyres, or are there brands fitted to the Z4?

@Z4andy - to be honest the steering does feel light to me no matter what mode it's in - but I kind of expected that coming from the M coupe. I am not convinced that changing to Sport + actually makes much of a difference to the steering on my car. Is it noticeably firmer in your car?

@Nickm - thanks for the offer - very kind! I am actually in London, so may take you up on this if the problem persists thank you!

[Nickm]

Def firmer in sport mode, and yes my car also has the Potenza Runlats....and on same wheels I assume as yours. 326 M Sport Alloys....

You're welcome to test against mine, I'm in West London....

[ChuckB]

If it had an alignment done and they did not center the electric steering first, then the alignment may be off. The electric power steering always tries to pull the steering straight, so if this is off, even though the steering wheel and tires are straight, then it will feel a bit wonky. Fund this out after an alignment at a non BMW shop.

[Gargybloke]

Wouldn't hurt to have a full alignment check at a place wth a Hunter or KDS machine. My z4m was twitchy lke this. Toe at front and back out. A big difference after. Cost around £45 I seem to recall.

[SuZ4]

Not sure if this is relevant or not but since we changed the tyres on our coupe from rf's the Michelin ps3's I've not been happy with the steering, sort of vague at higher speeds, it has been suggested that the tyres need to bed in and settle to the suspension settings. I also have a 350 e sport which I was guted with as anything over 80 required constant input, not ideal for European high speed travel, however this did improve massively,can't really remember when but it was after a few thousand miles, (coupe has only done a few hundred since the tyre change). I have to add I've never checked the wheel alignment on either car but am definitely going to have a four wheel alignment done on the coupe.

Corrie Phil

[MikeS]

I have the RF Bridgestones and 19" tyres and have no problems with the steering. Had the car from new and even at 150 mph (in Germany ) the steering was solid.

[jelmok]

It's good to hear that so many of you are finding this unusual - gives me some hope that I can improve things. As a first step I have booked the car into my dealer to have everything checked over - just to make sure nothing is amiss. If they find nothing, then will have an alignment done - does anyone know of a good specialist near London to do the work? I was thinking of trying Birds BMW specialists in Iver? Incidentally I dropped them a line about the issue and Kevin, the owner, wasn't surprised. Reckoned he has a demonstrator that does the same thing, and recommended ditching the run flats as a started for ten then suspension work if still not good enough! Sounds expensive....

[Andrew*Debbie]

Reckoned he has a demonstrator that does the same thing, and recommended ditching the run flats as a started for ten then suspension work if still not good enough! Sounds expensive....

Ouch. I'd start with the basics. Tyre inflation, alignment check, tyre check. Next thing to check is for slightly damaged or bent suspension parts.



I've had cars that didn't center well because of tire pull. The tread on one of the tires was very slightly off. Even though the car showed up perfect on the alignment machine, it didn't drive right. This was with non-RFT tires too.