Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

"M" Specific discussion
User avatar
99ron
Member
Member
Posts: 287
Joined: Tue Oct 28, 2014 6:25 pm
Location: Hampshire

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by 99ron » Sat Aug 13, 2022 5:22 pm

Front bump stops cut. Asked for 25mm off so still leaving a decent chunk of bump stop but at least compensating for the 20mm lower front springs.
Only driven about 30 miles since but seems a bit better. It still bottoms out on the harsher bumps but not with quite the violence of before. I tend to try and avoid the worst lumps in the roads but not always possible and without hitting them the car is generally better than before. I can live with it.

It miffs me that the B12 kit is specifically for the Z4M yet with the B6 shocks isn't really ideally paired with the Eibach springs. Not really fit for purpose as a kit straight out of the box. So more expense to remove them and trim the bumpstops and more expense to recheck the alignment again. Should have done my research better and realised there isn't a B8 shock for the Z4M that would work better with the lower spring and they instead give you a B6 designed for the OEM strings. Should have bought the KWv3s maybe. Shame ST suspensions don't do a Z4M kit. Lessons learnt. 🙄
Z4MR E85 for sunny day Hooning. 8)
Now with added joy of Gruppe M.

Matt.13
Member
Member
Posts: 185
Joined: Mon Jun 11, 2018 3:53 pm
Location: West Malling

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by Matt.13 » Sat Aug 13, 2022 7:22 pm

Would you say its worth doing ? I dont think the kit is that bad tbh, more so the roads where i live . I was booked in with eta motorsport last week but they had to cancel so i planned on doing it myself
2nd gear sideways

User avatar
99ron
Member
Member
Posts: 287
Joined: Tue Oct 28, 2014 6:25 pm
Location: Hampshire

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by 99ron » Sat Aug 13, 2022 7:35 pm

Well I guess running 19s probably doesn't help but before the bumpstop shortening I found the violence of some impacts were so unforgiving and used to make me wince. So stressful to drive. Now there's a bit more travel the eventual impact seems less severe and perhaps no worse than when I ran OEM shock with the H&R springs. Need to try it two up but so far I am glad I did it.
Z4MR E85 for sunny day Hooning. 8)
Now with added joy of Gruppe M.

Matt.13
Member
Member
Posts: 185
Joined: Mon Jun 11, 2018 3:53 pm
Location: West Malling

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by Matt.13 » Sat Aug 13, 2022 7:38 pm

Thanks nothing to lose i suppose
2nd gear sideways

User avatar
99ron
Member
Member
Posts: 287
Joined: Tue Oct 28, 2014 6:25 pm
Location: Hampshire

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by 99ron » Tue Aug 16, 2022 1:12 pm

Unfortunately do not have photos but Indie doing the bumpstop work said the stops were not the same as the ones in the pictures above. Much shorter, about 50mm which they then chopped in half. That seems a bit strange. I bought these brand new. Have Bilstein changed the design? Be interested to see what you find Matt.13
Z4MR E85 for sunny day Hooning. 8)
Now with added joy of Gruppe M.

maupineda
Member
Member
Posts: 139
Joined: Fri Apr 24, 2020 4:46 pm

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by maupineda » Tue Aug 16, 2022 6:56 pm

My photos are from H&R Bilstein struts. So they may be tuned to a different length. I think tunes to 25mm is as good as it can be

Bilstein shocks just have too much gas, and are valved ver aggressive.

Matt.13
Member
Member
Posts: 185
Joined: Mon Jun 11, 2018 3:53 pm
Location: West Malling

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by Matt.13 » Wed Aug 17, 2022 1:03 pm

Mine was the same i just put them back in as im not sure id want them that small. Lucky id only done one side at a time . Not he easiest of jobs to do with out a hydraulic spring compressor.
The kit is very firm no doubts about that and on smooth roads its great . I think you options are really to go back to standard front springs as a few on here have already done .
For me i think the z4m coupe is already stiff car and the b12 kit makes it stiffer.
2nd gear sideways

plenty
Member
Member
Posts: 327
Joined: Tue Sep 10, 2013 11:59 pm

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by plenty » Wed Aug 17, 2022 1:29 pm

99ron wrote: Sat Aug 13, 2022 5:22 pm It miffs me that the B12 kit is specifically for the Z4M yet with the B6 shocks isn't really ideally paired with the Eibach springs. Not really fit for purpose as a kit straight out of the box.
Exactly why I dismissed the Bilstein kit and opted for coilovers. First I didn't want to lower my ride height at all, not only because ground clearance is needed for the roads we have in the UK but also because in my experience lowering promotes body roll unless you add other mods such as roll-centre adjustment balljoints.

Second, a reduction of 20mm wheel travel is unacceptable to me on a car which doesn't have a lot of travel to begin with.

beanie
Member
Member
Posts: 834
Joined: Sun Aug 05, 2012 9:57 pm
Location: Bournemouth/Turin

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by beanie » Wed Aug 17, 2022 5:11 pm

It’s not the first time I’ve heard of bilsteins being labeled as a bit harsh.

I always thought it strange that something a bit more compliant hadn’t been developed given that ride quality is a common complaint and the majority of these cars will now benefit from new suspension. I know it’s a small market, but it seems so many owners want a smoother ride.

Then I stumbled upon this kit a little while ago.

https://balancemotorsport.co.uk/ast-51 ... m-kit.html

AST 5100 ‘comfort kit’ developed by AST and Balance Motorsport. I’ve no idea what’s been done in terms of spring rates etc but on paper it sounds a decent direction for a road driven Z.

I’ve not come across anyone using it and although it’s not cheap, it’s not crazy money either.

Edit- Curiosity got the better of me so I’ve sent them a mail asking for a bit more info. Hopefully they’ll go a bit deeper than the website does.
Image
RUBYIMOLACARBON

mmm-five
Lifer
Lifer
Posts: 12714
Joined: Sun Nov 30, 2008 1:03 pm
Location: Liverpool
Contact:

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by mmm-five » Wed Aug 17, 2022 7:32 pm

beanie wrote: Wed Aug 17, 2022 5:11 pm It’s not the first time I’ve heard of bilsteins being labeled as a bit harsh.

I always thought it strange that something a bit more compliant hadn’t been developed given that ride quality is a common complaint and the majority of these cars will now benefit from new suspension. I know it’s a small market, but it seems so many owners want a smoother ride.
That's why I went for the B16 PSS10 kit, rather than the more basic Bilstein options :P
Trigger’s Z4MC
Some bits now over 163,000 miles, some less than 1,000 miles.
Individual Ruby Black, Individual extended champagne leather, plus many options

Image

User avatar
abar121
Member
Member
Posts: 499
Joined: Tue Apr 26, 2011 9:14 pm

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by abar121 » Thu Aug 18, 2022 2:47 pm

beanie wrote: Wed Aug 17, 2022 5:11 pm It’s not the first time I’ve heard of bilsteins being labeled as a bit harsh.

I always thought it strange that something a bit more compliant hadn’t been developed given that ride quality is a common complaint and the majority of these cars will now benefit from new suspension. I know it’s a small market, but it seems so many owners want a smoother ride.

Then I stumbled upon this kit a little while ago.

https://balancemotorsport.co.uk/ast-51 ... m-kit.html

AST 5100 ‘comfort kit’ developed by AST and Balance Motorsport. I’ve no idea what’s been done in terms of spring rates etc but on paper it sounds a decent direction for a road driven Z.

I’ve not come across anyone using it and although it’s not cheap, it’s not crazy money either.

Edit- Curiosity got the better of me so I’ve sent them a mail asking for a bit more info. Hopefully they’ll go a bit deeper than the website does.
That is quite interesting. I also wondered if there are any other rear springs from the non-M Zeds, stock or otherwise that might help ride comfort, with matching shocks.

19" wheels are totally the wrong way to go for me, but I understand it's personal preference.
'07 Z4M Interlagos Blue. All options except extended leather.

User avatar
99ron
Member
Member
Posts: 287
Joined: Tue Oct 28, 2014 6:25 pm
Location: Hampshire

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by 99ron » Sun Aug 28, 2022 10:03 am

Quick follow up if it helps anyone else. I had the alignment done again. front -1.4 camber and 0.04 toe. Rear -1.5 and 0.06 toe. A few hundred miles later and things are getting better. Ride and handling is definitely better than what I had before, improved ride confirmed by the missus as passenger. I read elsewhere that others had reported +500 miles before it settles and softens just slightly. The bump stop mod has certainly given the front more travel and is helping. Two up with luggage trip to the Silverstone Classic yesterday and the car felt great again. If I made the decision again I would pay the extra and go coilovers but this isn't too bad once the bump stops are sorted and you avoid the worst potholes. Gary.
Z4MR E85 for sunny day Hooning. 8)
Now with added joy of Gruppe M.

maupineda
Member
Member
Posts: 139
Joined: Fri Apr 24, 2020 4:46 pm

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by maupineda » Mon Aug 29, 2022 4:00 pm

Glad to hear, I had the same findings. Modifying the stops makes a noticeable difference for the better. My H&R coils rode like s**t. I also left the ride height same as stock.

belcom
Newbie
Newbie
Posts: 3
Joined: Wed Apr 29, 2020 4:40 pm

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by belcom » Sun Sep 25, 2022 5:17 pm

I run this exact setup with Bisltein B6 all around and H&R springs. Shocks I bought new without Eibachs but inherited the H&R springs with the car and decided to keep these since I did not have originals. I did cut the internal bump stops in front shocks before install as Maupineda suggested. Mine were about 40mm to begin with and it made sense to simply cut them in half to 20mm because of their shape. So I have been driving the car around on the street for a while and have done a few track days/sessions with it. Although its actually a very decent suspension there are some fundamental problems with it.

1. It takes small bumps and cracks, road imperfections and smooth bumps with plenty of suspension travel and I'd say quite comfortably. However as OP states once you hit something fairly deep at speed you get a big boom through the shock tower as it bottoms out. Not a nice feeling at all.

2. The car sits too low for my liking on the H&R springs. Nothing you can do other than replace with Eibachs (to gain just a bit more clrearance up front) or go with coilovers, or potentially get a coilover conversion spring kit for Bilstein from Ground Control. I scrape my front lip on steep driveways at certain angles.

3. Disclaimer. I am not a pro track driver by any means... but I do have an opinion and some experience. On track it performs decent but at the end of the day I do not like it. The progressive nature of these springs makes them fairly soft on initial compression however the further it goes the harder it becomes and Bilsteins just don't work as well in those conditions under those extreme limits. And also because of the H&R's initial softness I get a fair amount of body lean in hard turns which is not ideal and I think it affects grip negatively. Weight transfer is also affected I believe and not ideal when you have to steer side to side in quick succession. It just kinda wobbles too much if that makes sense.

I had driven my friends Z4M with KW V3 and another friend's E46 M3 with Bilstein PSS10 and its completely different experience. Even though KW v3 are fairly soft you just don't experience similar body lean and there's plenty of grip, PSS10 are stiffer (well they're setup this way as its a dedicated track car) and also plenty of grip and no nonsense of any kind.

At this time I am on the fence. I do like the Bilstein B6 shocks and thinking the ground control coilover conversion kit might solve majority of my track "issues" at a fair price point. But you still don't get any type of shock adjustment and front shocks are still not the correct length for lowering springs. Or save up some cash and get proper coils. I do like the Ground Control school kit. I think its the most fairly priced kit on the market, 1-way adjustable Konis specifically shortened for Z4M, any spring rate you want, camber plates included etc.

But for street only B6s are awesome in my opinion probably more so with stock springs if you don't mind the gap.

Compaqnx
Newbie
Newbie
Posts: 20
Joined: Sat Oct 07, 2017 11:09 pm

Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?

Post by Compaqnx » Tue Dec 06, 2022 10:33 am

Can anyone send links to where to buy the shocks from?

Post Reply