Still no joy - self steering Z4

J

jnwright71

Member
All,

I posted a week or so ago about my self-steering Z4 (wondering, wobbly rear end, tramlining etc) and possible tyre choices to help address this. Hopz121 kindly suggested that I also get the RTABs looked at and potentially replaced. So yesterday my car was checked over by my trusted local indie and all suspension bushes and ball joints etc found to be rock solid. Indie also suggested that tyres were unlikely to be the issue (Pirelli P Zero Rosso 225/40 R18 92Y XL on the front and Pirelli P Zero 255/35 R18 94Y XL on the rear). Having driven the car, my indie has recommended a full alignment (done twice last year using a Hunter machine and less than 1,000 miles driven since - no potholes hit etc either) as he feels it is the only possible cause.

I am happy to do this, but my dilemma is the car has done 54K (2006 2.5si roadster), so should I just replace the RTABs anyway before paying for alignment ? any thoughts welcome. Have others replaced RTABS that are visibly OK and don't move much with a pry bar, and found a significant improvement ? If so; poly, OEM only, Meyle HD only, OEM + limiters; Meyle HD + limiters, AN Other ? I do around 1,500 miles per annum of reasonably sensible driving.

Cheers :thumbsup: :thumbsup:
 
electronic steering is the big issue, steering torque angle & sticky steering is the common problem, do a search on here for it. Run flats do cause tramlining
 
I have also posted, and added to other similar posts, several times lately on this subject. Having renewed everything there is to renew on the suspension (front and rear) and had 2 Hunter alignments carried out by two different specialists (just in case) I still had the symptoms you describe. I have standard M sport 18" staggered wheels (108's) and new non run flat vredestein vorti's fitted. I had about given up when I purchased a set of 17" alloys with winter Michelins on and put them on the car (couple of months ago). Guess what! problem gone. I have read many times that zeds are very fussy on tyres, particularly once up to 18" wheels, now I know just how true this is and your specialist may just be wrong. Your car may simply not be happy on Pirelli P zero's, just as mine is not on Vreds. Both great tyres, but something in the pattern or otherwise that doesn't suit our cars, who knows? If you are able to borrow a set of 16" or 17" wheels and tyres to try, I would recommend you do this before spending lots of money trying to solve the problem (like I did!). As long as all suspension is tight and the steering angle sensor is not at fault, my bet is the problem would be gone or at least very much reduced.
 
Another tyre models tramlines more than other. Good tips from midhurstman. 16-17" alloys will always be better to drive than 18".. less tramline, and more comfortable.
I have goodyear eagle f1 asymmetric 2 in my e46 17" and those are great..
 
Thanks Guys.

I know tyres can be a real issue, so was planning on getting GY Eagle F1s, but at circa £550 a set was looking to check other more affordable options first.

Does anyone in the Peterborough have a set of 16 or 17" wheels I could try ?

I would still appreciate feedback on the RTABs as I may do these anyway if the evidence suggests it is worthwhile.

cheers, James
 
All I can say is that I read all the stuff on RTAB movement, there are a couple of videos on You Tube with a camera attached looking straight at one of the bushes. When the car is driven you can see a lot of side movement as it goes up through the gears under hard acceleration. The contention is that this alters the geometry and can cause a type of rear wheel steering effect. I also read turner motorsports page on the limiter shims that they offer. I fitted new Meyle RTA bushes and side shims and it made absolutely no difference. My old bushes were still in good condition however and probably still doing their job well. I am sure that if the rubber has split and the centre steel part of the bush is no longer captive and solid, as usually happens with failed RTAB's, there would be a noticeable difference with new bushes fitted. Hopefully someone nearby will come up with a winter set of 17" wheels that are now off the car for you to try. I am in Midhurst West Sussex but if you are ever down this way, give me a pm and you are welcome to stop by. It wouldn't take long to put mine on for you and I have a nice straight bit of the A272 road within a mile of the house.
 
Cheers Midhurstman.

Hopefully some kind forum member will offer me a spin on their 17" wheels. The whole RTAB thing is a bit of a mystery. Some suggest it transforms the car whilst others state no difference.

I will definitely be getting the alignment done next Thursday and may be able to stretch to new front Goodyears by then. If I don't get a better feel for the value of replacing the RTABs then I will give changing them a miss. Should all this fail, I will be selling and using an awaited bonus + the Z4 money to get a Boxster or 3.2 TT. I would much rather keep the Z4 as I prefer the looks, but if I cant get to a stage where I enjoy driving it, then it will need to go.

Thx.
 
Joy, oh joy ....

Took my Z4 into my local tyre specialist this AM and had Goodyear Eagle F1 ass 2 tyres fitted to the front. Just completed a 20 mile test drive and what a difference !! More forgiving ride, feels more planted, steering more precise and little tramlining / wandering.

Time will tell if this is truly the whole answer, but very positive so far.

The tyre specialist also showed me that both tyre walls on the Pirellis ripped when the bead breaker was applied. In his opinion the sidewalks were rock hard which probably helps explain things.

Very happy so far and will report back after putting on a few hundred miles - Goodyear Eagle F1 ass 2 - great investment (only £198 fitted as well). :thumbsup: :thumbsup:
 
Cheers Grumpyowl,

Very relieved. It has taken some time, money and research, but hopefully there now.

Definitely a must for anyone experiencing the same issues.

Cheers, James
 
Midhurstman - feel free to say no as the offer wasn't aimed at me, but I am nearby and if it were possible would be extremely interested in a comparison with 17" wheels. And the A272 is one of my favourite roads :D

The Z4C is currently on 19" wheels. They look amazing and the grip is sublime, but the jumpy tramlining (which my Roadster on 18"s also had) drives me nuts and I knew it would be one of the first things I'd want to look at.

No worries at all if not :thumbsup: but thought I'd jump in and ask as it's on my mind and I saw your post!
 
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