Z4MR suspension refresh- advice

bigwinn

bigwinn

Elite
 Lincoln UK
Site Supporter
Evening all

I’m looking to refresh the oem shocks on the M.

It’s got eibach springs all round and rides well at the moment.

I’m looking at B6 or 8s as a starter for ten. I’ve heard bad things about how hard the ride is on b12s so steering clear of them.

I’m not keen to do coilovers as my perception is they are crashy (change my mind :rofl: )

What’s people’s experiences- should I look elsewhere brand wise?

Cheers

Stuart
 
bigwinn said:
I’m looking at B6 or 8s as a starter for ten. I’ve heard bad things about how hard the ride is on b12s so steering clear of them.
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The B12 is just a kit containing B6 or B8 shocks and Eibach springs, so if you want to avoid the reputation of the B12 kit then don't pair your springs with B6 or B8 shocks.

Your best bet if you like your current ride would be new OEM spec shocks, but unfortunately the only option for the Z4M is to buy these from BMW. As far as I know there are no aftermarket shocks available that are a close match.

There are coilover options available that are designed for road use and use very high quality dampers, but perceptions differ and you will find many different opinions on what constitutes a good ride. I recently fitted this to my car, and first impressions are very very good and not at all crashy, but it is noticeably firmer than the 80k mile OEM suspension I removed: https://balancemotorsport.co.uk/ast-5100-coilover-bmw-z4m-custom-kit.html

In any case, your rear shocks at least are probably toast, so it's definitely worth replacing or upgrading them.
 
Is that right? Great to know on the bilsteins as I thought the 6 and 8s were different spec

I’ll get a price for the bmw spec ones, but thanks for the link- good recommendation if you are saying that’s better than old oem fitment.

Cheers!

Stuart
 
..yes B12 pro kit is B8 dampers and Eibach springs. B8 is a shorter B6 damper. Nor sure if slightly firmer too.
 
According to Bilstein's website the only options for the M seem to be B6 or the B12 Pro Kit.

Good to know you like the Eibachs because a couple of people on here couldn't get on with them on the front, and went back to OE front springs.

If you were to consider coil-overs I would recommend avoiding H & Rs if you want any sort of refined ride! In fact I can't see the point of any coil-overs if the only adjustment is the ride height, because to allow for the reduced suspension travel the springs are bound to be shorter and presumably stiffer.

And coil-overs with adjustable compression and rebound get expensive. I made an enquiry out of curiosity at Bicester last year and was quoted £2,700 for supply and fitting a set of KWV3s. :o That sort of set-up may be a bit overkill if the car is only ever going to be driven on the road, although it does allow for adjustment to suit personal preference.

Otherwise it looks like it's OE or B6, unless Koni make something suitable?

After a ride in a 20K miler a couple of years ago if I take the plunge on renewing mine I'll be going back to OE. Compared to my car it felt like a magic carpet!
 
Mr Tidy said:
After a ride in a 20K miler a couple of years ago if I take the plunge on renewing mine I'll be going back to OE. Compared to my car it felt like a magic carpet!
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I’ve been surprised how well it handles from an ‘everyday’ perspective that doesn’t cr4p the bed when pushed.

It looks like oem will be the route on that basis… thanks for the input!!
 
The rears seem fairly standard and can fit other brands- is that correct?
 
There are no B8 shocks, period,

If you go the b6 route you need to cut the bump stop to 38mm. I would advise against lowering unless you do it right.

I have H&R coils which are a pure progressive bilstein shock, I cut the bump stop but kept the ride height stock and used a linear spring,

It work ok but the harshness is still there as they have high gas pressure
 
I had the same dilemma last year when I was looking to refresh my 18yr old stock suspension on my Z4MC.

Given that I wanted the set up for road and not track I wanted to buy new OEM. Whilst the rear struts were readily available from BMW, one of the front struts was showing as NLA and it appeared there was no stocks overseas too, and given such a low production model my local dealer was saying it was highly unlikely that BMW would be make another batch. I then thought about fitting a set of OEM struts for the roadster, but likewise the same issue, one of the front struts was NLA.

The good news is I got a call from my dealer last month to say that BMW have made another batch of front struts, however these are for the M Coupe, so not sure about availability for the roadster but surely worth a check??

Price wise, with a little discount I got the front struts for £660 and the rears for c£400 so just over a grand - not cheap but pleased with the result. Spring wise I opted for fresh Eibach's which IMO work well with fresh factory struts.
 
My entry-level BC BR coilovers both ride better and handle (vastly) better than the OEM parts they replaced, albeit the OEM dampers were almost certainly past their best. I've not experienced a car with fresh OEM dampers, however the criticisms published in reviews when the car was new were consistent with my experience (choppy and wayward rear combined with a weirdly soft and imprecise front).

The rear on BC BRs is still quite bouncy on rough tarmac, but I'm not sure that's entirely curable given limited suspension travel and how close the seat is to the axle.

The BC RM and DS series have better dampers than the BR still. Pick the default 5/8 spring rate for the road. And you can run OEM or higher ride height with BCs.
 
@bigwinn genuine BMW shocks all round will set you back a fair chunk and not much improvement.

Besides, it looks like the fronts are on back order until December 2025…although you may still be able to get them if you shop around…

A set of KW V3s will cost a fair chuck but if they are dialled in properly they will ride much better than any damper/spring set up.
 
KWV3’s on mine, yes expensive but adjustable for ride height, bump and rebound, transforms the car and worth it for the admittedly fair outlay. :driving:
 
KWV3 on mine as well, had to get used to the difference but after a few miles now I like the road holding. In the beginning it felt a bit crashy on the road. The parts bill was £2500 though
 
Stuart

How about you meet me somewhere between Lincoln and Manchester and we have a ride out in your car then mine to see the difference back to back

Everyone that changes the shocks and springs are changing worn out ones for new ones of whatever type make or model so 99% will be an improvement plus if you just spent 2K and a full day fitting them your wallet will tell you they must be better
 
PDJ said:
Stuart

How about you meet me somewhere between Lincoln and Manchester and we have a ride out in your car then mine to see the difference back to back

Everyone that changes the shocks and springs are changing worn out ones for new ones of whatever type make or model so 99% will be an improvement plus if you just spent 2K and a full day fitting them your wallet will tell you they must be better
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That sounds like a plan Paul- good idea (and great roads to blast on too!!)

I don’t think I have your mobile any more. If you can pm me it we can sort something?

Best

Stuart
 
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