Twitchy steering 35is - Update now FIXED!

Hi there my 35i runs on 296 with run flats in the summer and i
Got a set of 18" with winter tyres as you can't get 19" winter
runflats
And have to say this car runs straight and true in all situations
On both wheels/ tyre combinations bit softer on the 18" but
Not worth changing for comfort as the improvement in ride
Is negligible ohh I've got adaptive sports suspension don't
Know if that would make a difference to a standard 35i
Without it.
 
Sandygate128 said:
Hi there my 35i runs on 296 with run flats in the summer and i
Got a set of 18" with winter tyres as you can't get 19" winter
runflats
And have to say this car runs straight and true in all situations
On both wheels/ tyre combinations bit softer on the 18" but
Not worth changing for comfort as the improvement in ride
Is negligible ohh I've got adaptive sports suspension don't
Know if that would make a difference to a standard 35i
Without it.
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Good to know, and evidence to back it up. :thumbsup:
 
Maniac said:
So OP, did you get anywhere on this?
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So, dealer did the KDS and found settings out. However the tech verified the problem is still there. Reckon everything is as it should be so they are stumped and have raised a Puma case with BMW. Based on the number of people on here and on another forum telling me this is unusual, I am hopeful and have some good evidence to go back to the dealer should they start telling me it's normal or a 'characteristic'!

Nickm said:
I've heard a tyre dealer I know say that once you take the run flats off, the car is all over the place, and very slippery when driven....am sure this may compound the problem if the run flats are off.
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I was worried about changing them on my car but did so on the advice of Birds tuning. I must say the handling is no different in the sense that this issue is no better. The car seems a bit less unsettled by mid corner bumps though. One thing I had to do was make sure I got extra load tyres - apparently very important. Ride is far improved however. I have kept the run flats though just in case it does turn out to be related!

Nickm said:
You're still welcome to try mine, drop me a PM
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Thanks! Should the dealer tell me this is normal, I'll be in touch to have your car as some evidence. In the meantime I am going to point te dealer to this thread and the one on the other forum to give some ideas of what to check.

Kryton said:
OP, my old Z was a 35iS and there wasn't any twitchy steering at all

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Beautiful car! I Really hope I get this sorted - I really love my car in every other respect and don't want to change it. Thank you for all the suggestions - will keep topic updated!
 
Hi all,

Thought I would drop a quick update on this for anyone that is interested.  Had the car into a 3rd party BMW tuner to provide an independent report and initial analysis, and they confirmed the problem is there (so I'm not going mad)!  The owner even has a 35i himself which doesn't exhibit the same problem as my car.  They visibly checked all the obvious mechanical things and everything looked good, and confirmed that the KDS was done correctly.  So my car is now back with BMW.  Went out with one of the Master Technicians and he confirmed the problem was there, but warned it may take a while to diagnose and cure, as most of the obvious things have now been checked and even double checked!  Really hoping they can cure this problem - but at least they are taking me seriously and concur that there is something amiss.  Last I heard they were going to try disconnecting as many electronic aids as possible to see if it is some kind of erroneous interference from the adaptive dampers or the servotronic steering.  Hopefully I'll get an answer soon - don't really want to get rid of the car, but if they can't fix this, I can't keep it as it is....so fingers crossed!

Thanks for all the feedback and insights from everyone!   :)
 
I took my 35i in to have the tracking done as it pulls to the left.

Full laser alignment at a recommended place in Leicester, it was a fair bit out and they could not bring the rear camber into spec (I think that's the 1 they couldn't do)

Still pulling to the left abit though.... :cry:
 
Funny you should say that - the tech who took mine out today reckons many BMWs pull to the left slightly as a characteristic. Can't say I have noticed it with any other BMWs I have owned though.
 
Cars do pull to the camber side and as most roads have outer camber the cars pulls left, if you overtake you can feel right camber pull.

Having said that my car runs straight as a die and does not pull one way or another on acceleration or deceleration. I do get occasional steer when braking which is simply dirt on the brakes.
 
Maniac said:
I do get occasional steer when braking which is simply dirt on the brakes.
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I'm betting your not getting too much of that after your cars recent detail - looks beautiful btw :thumbsup:
 
jelmok said:
Hey, Just get rid of the runflats and put on Michelin Super Sports. What a diffence! Doesn't even feel like the same car. It will handle like a BMW should.

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.
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It's the tires. Runflats give a terrible ride. The only cure is to get high performance tires. The OEMs have no grip and give a hash ride aside from tracking. Shame on BMW. Get real tires. You can't put a shine on a sneaker! Allign all you want, but it won't help unless it indeed needs an allignment. However, it will always drive weird alligned or not. These Potenzas get terrible ratings. Not made for anyone not using the Autobahn. Even their I have my doubts. They are not performance tires period. Aside from that they are seriously overpriced crap.
 
Brian1 said:
It's the tires. Runflats give a terrible ride. The only cure is to get high performance tires. The OEMs have no grip and give a hash ride aside from tracking. Shame on BMW. Get real tires. You can't put a shine on a sneaker! Allign all you want, but it won't help unless it indeed needs an allignment. However, it will always drive weird alligned or not. These Potenzas get terrible ratings. Not made for anyone not using the Autobahn. Even their I have my doubts. They are not performance tires period. Aside from that they are seriously overpriced crap.
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Hey Brian,

Yep that was the first thing I did - car is on Continental Sport Contact 5p's now - still not handling right :(

Thanks,

John.
 
I think we should stop blaming the RFTs for every so called handling problem. I have my original RFTs and have never had any handling problems - in fact my 3 series on standard tyres tramline frequently on the worn parts of the local motorway and my Z is as steady as a rock on the same stretch. :poke:
 
Only thing wrong with the RFT's is the slightly harsher ride (certainly on 19's). My e85 tramlined all over the shop on 18" 108's, on my 19" 296's on the e89, no issue at all. As I said before only time I get any steering change is a slight pull left or right on heavy braking which is just dirty brakes as it stops doing it after a second or so of braking. A good clean usually sorts that.
 
Mine runs RFTs on 19" rims. It has absolutely no problems in tracking, running straight as a die, or braking and does not tramline in the slightest. I have only two criticisms of the RFTs. Firstly the rears tend to hop sideways a bit during tight cornering on very broken surfaces - I put this down to the tyres just being too stiff in the sidewall to cope with such rutted surfaces. Secondly, the traction drops off markedly below about 5 degC, the back end will slide in the bone dry with very little provocation at these temperatures - again, probably a combination of the normal drop off in grip of the tyre compound coupled with the stiff tyre walls getting stiffer still at low temps.
 
Mine is the same, 19" with run flats and no movement at all, runs straight on motorway, can hold with one finger, and no tramlining or pulling under braking. I was actually pretty impressed with the ride with 19". I do notice in the wet the tyres can loose traction quite quickly, and the only downside is road noise can get a bit high on certain surfaces.
 
MikeS said:
I think we should stop blaming the RFTs for every so called handling problem. I have my original RFTs and have never had any handling problems - in fact my 3 series on standard tyres tramline frequently on the worn parts of the local motorway and my Z is as steady as a rock on the same stretch. :poke:
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Must admit although my car isn't handling right, and I have only had a short time with my car, I do resonate with this. Having come from an M car without RFTs I was a bit predisposed to thinking the tyres could be a problem when I bought the car. This despite the fact that my old M coupe used to ride as hard a nails on standard tyres! In fact when I first test drove my new car, one of the things I liked about it was the fact that it actually rode quite well on the RFTs. When a specialist, who to be fair hadn't driven my new car, suggested the tyres were probably at fault with this issue on my new car, it played into my predisposition, and I just changed them, in the hope it would fix the problem. It didn't - just cost me more money, but admittedly gave me a nicer ride!

What I should have done is trust my instincts that BMW wouldnt have released a car that handles like mine is doing, and just been persistent with the dealer. Everyone who has driven my car admits its not right, but they just have no idea how to fix it. However, I am now quite certain that the RFTs are not to blame, at least in my cars circumstances.
 
Nickm said:
Jelmok what did you with the tyres you took off?
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So far nothing. I figured if BMW tried to tell me that the problem was somehow because of the tyres I would have them ready for them to test to prove otherwise. Also if they don't get the car fixed, I will return it to the original dealer with the original tyres and sell the Continentals.

Are you interested in buying them? if so drop me a PM and let me know. If they do fix my car, which I am hoping, will sell them on as they are virtually new!
 
Mate I'll take them off you, either the run flats or the non run flats..either way am easy. I just got two used ones for the rear thinking I will switch all mine over when they wear out....but the fronts are pretty new still, so may as well get some in and leave them in the garage
 
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