Z4 2.5si handling issue

[Reddy]

Hi guys,

I have a z4 2.5si, with 19in rims.
After changing my rear tyres, I have noticed the handling around corners is very unstable? The same feeling when there is a strong wind blowing.

I have also had the shocks tested. The front drivers side shock needs to be replaced soon as well.

Any ideas guys?

 

[MikeR]

is it still under Motor Plan ? then they will replace shocks.
what tyres did you put on, possibly they dont grip so well.

 

[Reddy]

Hi MikeR
No motor plan.
I have Achilles on. Doesn't feel like a grip issue. It's more like the feeling when a strong wind hits the car from side.

 

[jcwdrop]

Can you think of any other way to describe this problem? Is it an issue of too much body roll?



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[sherwinZ]

Have you checked the tyre pressure?
May be over inflated when they fitted the tyres.

 

[tinovittee]

Have your alignmnet checked... did you do so after you changed tyres?

Also, with brand new tyres on the rear, it's not unsual to have it feel a bit light for the first few 100kms... had the same issue with new bridgestones on my e86. It apparently has something to do with the camber, although the camber angles are configured to increase grip in the corners, so not too sure.

If the shocks and the alignment are both right, then give the tyres some time to bed in first and if the problem persists then investigate further. :dunno:

 

[Blue Shirt]

The Z4 is notorious for nervous handling and tram-lining unless everything in the suspension is set up correctly. From your description, I suggest the following:

• Different brand tyres front/back - replace all four tyres at the same time or at least with the same brand.
• Wheel alignment needs to be done
• Incorrect tyre pressures
• Worn shocks
• Loose wheelnuts

I also had some nervous handling issues with my Z4, after replacing LCB's and shocks in the front, a decent alignment and setting correct tyre pressures, the problem disappeared.

 

[moranor@axis]

If alignment was not done its probably the tires... different sidewall construction can cause issues because the sidewall affects the dampening properties of the tire...

If alignment was done then they could have not done a good job

1st step is to check tire pressure this has a great effect on how a tire behaves under lateral load

2nd is to do alignment and make sure it is spec

also shock testers are not really a reliable way to test shocks... general rule is if a damper is close to 100 000km it is finished...

 

[MikeR]

:rollsmile: these cars are very twitchy around corners to start with.
Well mine is especially under acceleration in corners all the time. :rollsmile:

 

[Reddy]

Gents,
Thank you for the feedback.

Does anyone have the correct wheel alignment and camber specifications? I believe my rear cambers are set quite negative. Could this be an issue?

Nb: same spec tires all round.

Appreciate the responses thus far.
Thank you.

 

[moranor@axis]

should not be the tires if they the same all round...

PS did you get my quote on dampers? been having trouble with my email...

 

[Reddy]

should not be the tires if they the same all round...

PS did you get my quote on dampers? been having trouble with my email...

Hi there,
Gonna check wheel alignment again. Tighten up loose bolts,etc

Thanks I did get the quote.

 

[S1NGH 911]

A long shot here, what's the current state of the control arms ?

 

[moranor@axis]

Great let me know if you need the dampers

 

[sash]

what tyres did you have before? could it not be that the achilles is quite a step down to your previous tyres in terms of grip?

 

[Reddy]

Gents,
Went to Tiger Wheel. Found out that the front passenger tyre is "separating". The front driver tyre has slight uneven wear. So I am going to change them.
Let's hope after that, balancing and alignment, the issue goes away.

Btw: Blue Shirt, the feeling I get can be described as "tram-lining" or nervous handling.

Moranor: thanks for the specs.

With regards, to shocks. Considering my car is out of motor plan any suggestions and views on replacement shocks?

Nb: car has been lowered using AC Schnitzer springs. Was done by JSN.

Thanks

 

[andrewbuch]

Get all replacement suspension stuff from moranor

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[Blue Shirt]

Glad you found the problem. Let us know if the new tyres have solved the handling issues.

 

[moranor@axis]

Glad you sorted

Achilles seem to separate way to often for my liking...

you wont be sorry with the Koni Sport I quoted on :rollsmile:

 

[Reddy]

Gents,

The new Achilles 2233 are much better, softer ride and grip is back.
No instability issues around corners.
One of the front rims has a slight buckle, picking up a slight vibration after 120kmh. Will sort that out, thereafter I will sort the shocks out.

Ciao