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My impressions and suspension height measurements after 1300 miles on Bilstein HD struts / shocks with reused stock springs

2K views 3 replies 3 participants last post by  Rontgen 
#1 ·
This is not meant to be a scientific conclusion but the impressions of a long time E39 owner.
It's also important to mention that my wife and 9 year old daughter don't consider it harsh as many people on internet make the Bilstein B6/HD to be.
Obviously, it's different preferences with different people but I mention my family as non car enthusiasts liking the Bilstein suspension.
Also, I suspect that some negative reviews come from people who match wrong type of struts / shocks with wrong type of springs.

So first of all, according to catalog, these are 540i Bilstein 35-114086 / 24-028288 meant to be used with stock springs, not lowering springs. You can get all 4 of them for about $550 which I consider a great deal.

Also, and it's been debated here, these are not approved for M5 according to Bilstein even though they're 100% direct fit. Yes, the rear ones will be slightly higher due to different perch height but IMO they look not too high and more importantly car handles extremely well.

I also personally don't like the slightly lower rear than front but that's me.

It can be argued that even though it's direct fit, maybe Bilstein doesn't approve them because M5 is heavier than 540, the springs have different rebound etc... but I can safely say I don't feel anything unusual with this setup but only superior handling to stock suspension in every way.

I also have the same Bilsteins on my 528, X5 and i had them on 540 that I sold. I've literally driven over 100k miles on this setup in different cars.

My main comparison comes from tired stock struts / shocks with 108k miles on them but still, the difference is amazing. My #1 with Bilsteins is control. You point the car where you want to go with almost regardless of speed and curve and you will get there with no drama.

The car is firmly planted at just about any speed and rebound is firm and short but not harsh.

My info from TIS states that E39 M5 stock suspension height is 605 mm front and 578 mm rear. I'm assuming that includes full tank of fuel, 150 lbs in each front seat and 150 lbs in middle of the rear seat aand 50 lbs in trunk (500 lbs) total as specified in Bentley.

I thought I measured the stock height before installing the Bilsteins but I can't find the info.

Anyway, here are my current measurements with 3/4 full tank of fuel and without 500 lbs in the car. I want to do the proper measurement later because I'm sure 500 lbs will lower the car few mm.
But even without it, it's within 10 mm allowed difference up front but not in the rear. Even so, IMO car still doesn't look very high in the rear and I really have no complaints.
So, the current measurements of my car:
F- 615 mm
R- 607 mm
I will update these once I do the proper measurements with 500 lbs in the car.
Also, these are measurement form the bottom lip of the wheel to the edge of the wheel well as per official BMW way of measuring.
I hope this will help somebody in deciding of to or not to go with these according to his / her preference but I have no regrets.
I've also installed all new components: spring pads, wheel bearing up front, mounts, etc...





 
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#2 · (Edited)
Bilstein is an excellent choice for a lot of vehicles. Yiire probably correct regarding tge springs. Pretty sure Bilstein recommends using the original types springs. Surely you start swapping different springs in and it probably won't get better than that.

I'm considering them to replace the 150k mile shocks on my X5. I still have the 95k mile springs from my M5 and have been thinking of getting Bilstein shocks for it and replacing the GC setup I have now. I love the GC stuff but my tastes have changed over the years. I like the adjustable camber option in front, though.
 
#3 ·
Yes, it's easy: HD /B6 are designed for stock springs, B8 for lowered springs. I've read where people used B6 with lowered springs and B8 with stock springs. That's plain stupid.
The specific strut / shock has certain length and valving for a reason. If you compress spring past its designed point or don't compress it enough, you're not getting intended rebound.
These are basic facts of suspension work yet people ignore it.
I love Bilsteins on my X5 plus I got rid of rear air suspension. I found high quality German made Suplex rear springs that work well in conjunction with rear Bilsteins.
 
#4 ·
Correct. The key difference between the B6 and B8 is the length of the shaft, and therefore the spring it’s designed to be used with.

I have the B8 with lowering springs and I’ve been very happy with it overall
 
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