E89 suspension

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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Pbondar
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E89 suspension

Post by Pbondar » Wed May 15, 2019 9:45 am

A-minor wrote:
Mon May 13, 2019 7:12 pm
Having had my E89 for a couple of months now I have to admit the ride is not quite as forgiving as I was hoping for. It seemed a little firm on the test drive before buying, and on good quality roads I have no issues with it. However, there seem to be plenty of 'bumpy' roads in this part of the country and on longer drives it does become a bit tiresome. I've already removed the runflats, and whilst that has taken the harsh crashy edge off the bumps, it didn't make the overall difference I was hoping for.

Now perhaps I'm just getting too old for this sports car malarky, but before arriving at that conclusion I'm considering whether at 113k miles some of the suspension parts are worn and need renewing. Could worn shocks could be give a harsh ride? It's seems counter intuitive but I wonder if an underdamped car results in a 'bouncier' ride, i.e. bumps are felt due to shocks allowing more vertical movement.

Another thought is that I noticed the rear springs were changed at an indie around 18 months ago. The cost was £95 per side including fitting; at that price I'm wondering if they were cheap non-original springs that have affected the ride. The car does look slightly lower at the back, perhaps they were cheap lowering springs? If anyone could help rule this out I'd be grateful, I've measured a vertical distance of 352mm from wheel centre to underside of arch, if anyone can give me a comparison measurement on their car it would be appreciated.
Well IMHO you have a perfect storm...

If you have not had the shock absorbers replaced than at 115k miles they will be unbelievably shot...

Somebody putting lowered springs with a higher spring rate to compensate will severely compound the problems.

The money spent would not have paid for new shocks...

So I suggest you need new shocks at a minimum...ideally you would do the springs and shocks as a matched exercise..

At least what you could do is go for Bilstein B8 shocks which are matched to reduced height springs..

I replaced my shocks at 40k miles and there was a dramatic difference...

For comfort B6 and OEM length springs would give you the most comfort...

What wheels/tyres are you running?
2012 E89 20i MSport Auto Atacama Yellow Changes (Wheels/Tyres/Spoiler/Steering Wheel/Shock Absorbers/ARB/Diff/Diffuser/Brakes) Upcoming changes (Speakers) Full Whippy here!

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E89 suspension

Post by Player 1 » Wed May 15, 2019 9:56 am

I've also been thinking it might be worth changing shock absorbers as time goes on, I've got no leaks and it doesn't bounce at all if you push down on them but after nearly 10 years and miles of punishment there's no way they can be close to 100%.

I think these cars do just sit quite low at the rear naturally as on mine below, also seems to be common for the drivers side rear to be a bit lower than the passenger side. That's not something unique to the Z4 either, a lot of other BMW's being the same.

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2009 E89 35i, Black Sapphire with lots of toys and the correct gearbox :P

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E89 suspension

Post by Player 1 » Wed May 15, 2019 9:58 am

Out of interest, does anyone know who make the OE shock absorbers for E89's? I had Sachs in mind?
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Pyranha
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E89 suspension

Post by Pyranha » Wed May 15, 2019 1:10 pm

A-minor, Do you have run flat tyres on the car? I just ditched the run flats and went to 4 normal tyres and it made a big difference to the ride quality. It is more more compliant now, especially on poor road surfaces.

Also is the ride just too hard or are you getting noises when you you hit an uneven road surface that is making it seem worse than it is. I was just thinking at 100k+ miles the bushes and suspension mounts might be worn.
Last edited by Pyranha on Thu May 16, 2019 9:25 am, edited 1 time in total.

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E89 suspension

Post by A-minor » Wed May 15, 2019 7:26 pm

Pbondar wrote:
Wed May 15, 2019 9:45 am
If you have not had the shock absorbers replaced than at 115k miles they will be unbelievably shot...
So I suggest you need new shocks at a minimum...ideally you would do the springs and shocks as a matched exercise..
I might whip a wheel off at the weekend to see if there are any markings on the springs, but either way I think I am leaning towards the suggestion of doings shocks/springs as a set, it just makes sense at this mileage.

The wheels/tyres are 18" staggered as per stock specification, except for the tyres are non-RFT.
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E89 suspension

Post by enuff_zed » Wed May 15, 2019 7:32 pm

Pyranha wrote:
Wed May 15, 2019 1:10 pm
A-minor, the bushes and suspicion mounts might be worn.
Are you sure or do you just have a sneaking suspension? :wink:
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E89 suspension

Post by Pbondar » Wed May 15, 2019 7:41 pm

A-minor wrote:
Wed May 15, 2019 7:26 pm
Pbondar wrote:
Wed May 15, 2019 9:45 am
If you have not had the shock absorbers replaced than at 115k miles they will be unbelievably shot...
So I suggest you need new shocks at a minimum...ideally you would do the springs and shocks as a matched exercise..
I might whip a wheel off at the weekend to see if there are any markings on the springs, but either way I think I am leaning towards the suggestion of doings shocks/springs as a set, it just makes sense at this mileage.

The wheels/tyres are 18" staggered as per stock specification, except for the tyres are non-RFT.
WELL IMHO, that’s a good approach, 18 rims with most non rft tyres in themselves should offer a reasonable ride...as other posters mentioned at that mileage the various linkages of which there are many may have perished rubbers..up on a ramp it becomes more obvious..

I’m impressed with the bilsteins but there are others..they do a kit with a German spring supplier..
2012 E89 20i MSport Auto Atacama Yellow Changes (Wheels/Tyres/Spoiler/Steering Wheel/Shock Absorbers/ARB/Diff/Diffuser/Brakes) Upcoming changes (Speakers) Full Whippy here!

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E89 suspension

Post by flybobbie » Wed May 15, 2019 8:48 pm

I have Bilsteins, B6 i think, the ride is great and they are manufactured to a much better quality than what came off. My standard shocks looked cheap and worn at 45k. Liked them so much also changed the front. After replacing the RFT, probably the best mod.

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