Bilstein b6 with stock springs
- Thread starter Sajk
- Start date
I have just been through this. I had eibachs and stock shocks. I too was fed up with the ride and was considering going to stock springs, to see if that helped because I thought my dampers were fine and I thought OEM couldn’t be this bad. However as the springs control the height and not the ride and as my car has done 50k and is 16 years old I took a punt that the shocks were shot. Anyway long story short putting on the Bilstein dampers raised the height of the car considerably over the standard dampers. I had many conversations with Bilstein saying this wasn’t correct but in the end had to concede that the height I had was actually as specified, all be it at the top of their tolerance. The thing is that my dampers although seemingly fine were obviously well past their best and the ride now is amazing, I did change all the mounts etc at the same time so this will have helped. I was also unhappy with the new raised look and so have bought some bigger tyres which have a larger side wall which of course helps. But my point is, if you are running with original OEM shocks, the chances are that they are ruining the ride and need changing.
LawrenceW said:
No longer listed on the Sachs online catalogue so I assume not. For normal fast road driving you can't got wrong with the Bilstein B12 kit which is Eibach springs and Bilstein B8 dampers, 100% improves the ride and predictability of the car. Ride height of my car with the B12 kit and OE CSLs attached.
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GT Spec said:
I was interested to see that in your B12 kit came with B8 dampers. I wonder if this has changed as all the B12 kits that I saw came with the B6 dampers (https://www.larkspeed.com/bilstein-b12-pro-kit-suspension-kit-837666/). It would explain why my ride height was high and more OEM. I had endless discussions with Bilstein through Larkspeed, and they insisted that the height was correct, and at no point mentioned that the dampers should have been B8. If the ride hadn't been so good I would have sent them back, instead I bought some bigger tyres that look great, make the ride even better and give me the look I am after. I was running 265/30/19's on the back and wouldn't recommend this kit to anyone running that tyre size, unless they like the 4x4 look!
I’m no expert, but in theory yes, as the springs control the height. However as Maupinda said and I agree with him, the b6 have too much gas and control the height along with the springs. Of course if you removed the springs altogether then the dampers wouldn’t hold up the car so the springs do influence the height and therefore you would imagine that changing back to stock springs would raise the height slightly, but my guess is not by much. Below are two pictures one before changing so stock dampers and eibachs. The second picture the same springs but B6 dampers. Everyone has their own opinion, but personally I hated the arch gap. To close the arch gap I have ended up changing the tyres and now love the look, but added expense that I wasn’t expecting.
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TheTJunction
New member
Just been through the exact same thing. My Z4MC cracked a rear OEM spring last year, and having researched this topic extensively I decided on spending money to move to the Eibach Pro Kit, consisting of brand new Bilstein B6's and new Eibach springs. Initially I felt that the front end vagueness and lift that the car always suffered from improved hugely, with greater balance and fluidity between the front to rear wheelbase. It didnt seem any harsher. However living with the car became very difficult given the state of our roads.
The dreaded "BANG" when hitting the bump-stops when cruising over a pot hole, low iron works etc on the UK roads led me to rethink it. I inspected the now removed stock shocks, and they seemed fine (all 4 would retract consistently after compression), so I was going to put the old stuff back on.
Now bearing in mind that the car only has 44k on the clock, but is 16 years old, I instructed my Indy last week to keep the new B6 shocks on the car, but replace the Eibachs with new OEM springs.
All I can say is that the car is a joy to drive again. The front end lift on standard shocks appears to have gone completely. It feels almost as planted as with the Eibachs, but no longer hits the bump-stops, and I can take speed bumps again with confidence that it won't bottom out.
The Z4MC appears to be very low already, and my honedt advice having been through this is NOT to lower it further. It will in all likelihood totally ruin the cars dynamics on UKs roads.
The dreaded "BANG" when hitting the bump-stops when cruising over a pot hole, low iron works etc on the UK roads led me to rethink it. I inspected the now removed stock shocks, and they seemed fine (all 4 would retract consistently after compression), so I was going to put the old stuff back on.
Now bearing in mind that the car only has 44k on the clock, but is 16 years old, I instructed my Indy last week to keep the new B6 shocks on the car, but replace the Eibachs with new OEM springs.
All I can say is that the car is a joy to drive again. The front end lift on standard shocks appears to have gone completely. It feels almost as planted as with the Eibachs, but no longer hits the bump-stops, and I can take speed bumps again with confidence that it won't bottom out.
The Z4MC appears to be very low already, and my honedt advice having been through this is NOT to lower it further. It will in all likelihood totally ruin the cars dynamics on UKs roads.
Also running the B12 kit. Previously ran standard shocks with H&R springs. Ride was harsh and on a bumpy b road found myself slowing as the car tries to throw me out of the seat. Probably knackered shocks rather than the lowered springs. B12 kit seemed perfect for my needs. My issues were the same as reported here. Rear in particular seemed much higher, although Eibach is a 10mm drop vs 25mm of the H&R. Looked just like ShaunKCs picture. Haven't got a recent picture and the car is filthy after a trip to goodwood last week so not.going to post one now but 1000+ miles later and the height seems to have settled a little. Most of the time the ride and handling is excellent and has improved with miles. Certainly doesn't throw me around like the old setup did previously and some bumps you wince in expectation of a thump but the car shrugs them off. Its sharp hits, like raised drain covers that really cause the problems. Not enough travel in the suspension. The front really the issue. I am also on 19s so I'm sure that doesn't help but really the kit should come with a B8 designed to work with the lower springs. Also thought about standard springs with the B6 shock but they are known for snapping and don't seem that great an option. Checking on cutters it seems the same issue with the E46 M3 also having the B6 in the B12 kit. It does improve with miles as I said but you're constantly eyeballing drain covers and pot holes. State of our roads we'll all be driving with 60 profile tyres on 17s soon... 
BTZ461 said:
I went for 275/35/19 on the rear, I had 265/30/19 previously and after spending some time on http://powerdog.com/tiresize.cgi it was a toss-up between 275/30 or 275/35 I went for the latter because the difference in tyre wall was only 4mm from what I had if I went for 275/30 and by the time of purchase I was desperate to close the gap in the arch. I'm glad I did because this tyre size fills the arch perfectly, and there is no tyre stretch which is something I was keen to get away from plus the wide tyre looks great from the rear! Having said this, some may prefer the smaller tyre wall of the 275/30's, to give more wheel arch clearance. With the wider, taller tyre I now need to do something with the front, either spacers or wider tyres to balance up the look, so more expense is on the way!
Sajk said:
When I was disputing the height, Bilstein sent (via Larkspeed) this information...
I’ve spoken with Eibach and their official data collected post fitment of their pro-kit during development was;
Front 348mm
Rear 358mm
These are from wheel centre to top of arch lip and also carry a +/-5mm tolerance.
My car is (as best I could measure) 364mm, so at the top end but basically within tolerance (+1mm). Eibachs are supposed to drop the car by 10mm. So on standard springs assuming the same tolerance at the rear 368mm +/-5mm
