Lowering springs and Bilstein HDs ... possible?

[Marvin_Hecht]

My 325e has a new pair Bilstein Sport's on the back ... I called Bilstein and they had said that I can run sports even with the stock springs...in the back.

For the front, I currently have Monroe's in there that I want to swap out for the brand new Bilstein HD's (non-sport) from my (for-now) parts car.
I know this would work without any issues on my current OEM springs..

But...from reading here and other places I am told that you can't use Bilstein HDs with lowering springs (eg H&R) since that might break the shock...is this true? Eg Bilstein HD in the front with H&R lowering springs.

In another post on this board someone said it was OK to use e30 M3 springs with Bilstein HD's...while there is not much lowering with M3 springs, if that is true...that might be a good compromise?

[Mystikal]

Word on the street is HD's have the same compressed length AND valving as the Sports. They are good to go for lowering springs, as much as Sports are.

[Henna Red]

all bilsteins have rebound, any gas shock does.

Theres a set height and loaction for the valve in the shock tube. So if it is too compressed/low in the shock, it will constanly try to return to medium [constant rebound] thus wearing out the seals inside the shock. As well as causing it to have a floating feeling in corners [too much rebound]

Altho, i have a set of HD's on h&r sports that have not worn out in about 6 years of use. So, i guess not :?

[Bavarian3]

I would do some more searching... though this board (and others) has a lot of mis-information....

The HD's are not made for 'lowering' springs...[final]

If you want to use E30 M3 springs, you can use HD shocks, since they are 'stock' springs.

If you want to use aftermarket 'lowering' springs (stiffer than stock rates) then use Bilstein sports.

HTH

[Mystikal]

I would do some more searching... though this board (and others) has a lot of mis-information....

The HD's are not made for 'lowering' springs...[final]

If you want to use E30 M3 springs, you can use HD shocks, since they are 'stock' springs.

If you want to use aftermarket 'lowering' springs (stiffer than stock rates) then use Bilstein sports.

HTH

This is what marketing would lead you to believe, but someone on the forum(can't recall who) actually spoke with Bilstien and discovered that they have the same compressed length. It's already well known that the valving is identical, but the length info isn't common knowledge.

[bmwdude]

Valving is the same on both.

I remember this question being asked in the Roundel' s "Tech Talk" also, and Mike Miller writing something about Bilstein advising against installing the HD's with shorter springs. Unfortunately, I don't remember the actual facts as to why.

If you are someone out there who wants to go ahead and do this, I would suggest to first pick up the phone tomorrow, call Bilstein's 1-800 number, ask for the tech. department, be firm with your question(s), and hope that you are talking with an actual tech/engineer on the other line, and go with that.

[Marvin_Hecht]

Thanks. I will call tommorow. I had spoke to the tech person about whether I could install Sports on the rears on OEM springs and they were right...it worked. So they should know.

Also..would the car actually sit higher in the front with the HD's--because the shock is pushing back wanting to push back to a taller position..i can tell this is probably negative since it's the springs that are responsible for the ride height...:(

What is the best place to buy Bilsteins cheap? The lowest price I can find is about $105 each for a front HD sport shock.

[Bimmerfanatik]

Thanks. I will call tommorow. I had spoke to the tech person about whether I could install Sports on the rears on OEM springs and they were right...it worked. So they should know.

Also..would the car actually sit higher in the front with the HD's--because the shock is pushing back wanting to push back to a taller position..i can tell this is probably negative since it's the springs that are responsible for the ride height...:(

What is the best place to buy Bilsteins cheap? The lowest price I can find is about $105 each for a front HD sport shock.

Just out of mild curiosity, since Bilstein sports are known and proven to be ok to use with lowering springs....and you already have bil sports in the back....

WHY ARE YOU TRYING TO BUY HD's? Why not just buy a pair of friggin sports and be DONE with it? Is it because they're cheaper? Maybe they're cheaper for a reason.

And to everyone who says they're identical in valving and compression to sports...why would Bilstein call them HD's and sell them seperately? If they're identical to sports...just call them sports. There's gotta be a reason they're labelled as different shocks.

[sovann]

This is what marketing would lead you to believe, but someone on the forum(can't recall who) actually spoke with Bilstien and discovered that they have the same compressed length.

I suppose you need to be careful with definitions here tho. Compressed length is typically measured at a metal on metal condition (ie. damper fully compressed without a jounce bumper). Maximum effective jounce (MEJ) is a compressed length measurement that includes the compresed jounce bumper solid height.

Afaik, the problem with the HDs and lowering springs only applies to the fronts. They're an upside-down monotube design (as are the Sports) with an internal jounce bumper. From what I've heard, the HDs have longer, more progresseive internal jounce bumpers than the Sports and are therefore more prone to bottoming.

And Henna Red, I don't think you know anything about how dampers work. Modern damper valving is speed sensitive, not position sensitive.

[Bimmerfanatik]

From Bav's site:

BILSTEIN HD's:
Bilstein street shocks will give you an unparalleled combination of comfort and control when paired with BMW springs.

BILSTEIN SPORTS:
Engineered specifically for use with lowering (sport) springs. Years ago, sport shocks had a reputation for providing a harsh ride. That’s not the case with the new generation of Bilstein sport shocks. Patented “digressive valving” delivers exceptional road handling and cornering stability with sport springs… without the harsh ride.

Hmm.

[Xmarksthespot21]

From Bav's site:

BILSTEIN HD's:
Bilstein street shocks will give you an unparalleled combination of comfort and control when paired with BMW springs.

BILSTEIN SPORTS:
Engineered specifically for use with lowering (sport) springs. Years ago, sport shocks had a reputation for providing a harsh ride. That’s not the case with the new generation of Bilstein sport shocks. Patented “digressive valving” delivers exceptional road handling and cornering stability with sport springs… without the harsh ride.

Hmm.

Didn't you know bilstein is a retarded company? They like wasting money engineering and designing "supposedly" different shocks (HD and Sport) when in actuality they are really the same shock. Bilstein is just trying to scam us by selling the same shock for the SAME price.

[Marvin_Hecht]

Beemerfanatick:

As stated near at the beginning of the thread, I can get a set of 1-year old HD's out of my non-running/parts car that i have already "paid" for. If I went with Bilstein sports I would have to buy them new or find someone sellling them here. The cheapest place I can find is eapparts (or similar ULR) for like 104 each thus slightly over 200 with shipping. Wouldn't have to take them out the HDs from the parts car then either (saves my time and labor). I have a pair of used M3 boges that i would put into the parts car if removing the HDs so that it is still intact/would be able to be parked on the street. As I am typing this I am realizing that it is not worth the hassle to take the HDs even for my own time doing this BMW stuff as a hobby....plus will add to the selling features of the parts car which will most likely get resold as a beater/roller/project car. I thought of parting it out (see seperate thread) but that will take too much time and labor and I don't have the space in my garage-need to park it on the street and keep it looking decent...

[Bimmerfanatik]

Didn't you know bilstein is a retarded company? They like wasting money engineering and designing "supposedly" different shocks (HD and Sport) when in actuality they are really the same shock. Bilstein is just trying to scam us by selling the same shock for the SAME price.

OOOOOOOOOOOOOOOHHHH.

I totally forgot. My bad.

[Bimmerfanatik]

Wouldn't have to take them out the HDs from the parts car then either (saves my time and labor)....As I am typing this I am realizing that it is not worth the hassle to take the HDs out even for my own time doing this BMW stuff as a hobby....

I, sir, rest my case. :)

[AdamF 88iS]

HDs won't last long on a lowered car; and this I know from experience. You'll need sports. Quit being so paranoid about and marketing schemes and stick with what is known to work.