Anyone running Bilstein B8 (from B12 Pro Kit) with H&R Springs?
- Thread starter 99ron
- Start date
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.
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.
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.99ron said:
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.
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-5100-coilover-bmw-z4m-custom-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.
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-5100-coilover-bmw-z4m-custom-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.
beanie said:
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.
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.
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.
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.
