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BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > Suspension | Chassis | Brakes > Why Bilstein B6/B8s Change Your Ride Height
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      02-19-2020, 10:48 AM   #23
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Quote:
Originally Posted by DriveS View Post
Ok. There is no doubt that when out of the box the shocks will return to the extended position when compressed. In installation of rears I used a strap to hold the piston in the compressed position.
From what you are saying, if held at this position, the pressure in the tube will equalise after a period of time and the position will not extend back to the original position without being pulled. If this is the case, then I agree that piston force had nothing do do with ride height as there wont be any force after a certain period.

Is this what you are saying?
The force that causes the piston/piston shaft to extend is the gas force, and that is the force I'm saying is "lifting" the car higher than the OE damper (which has lower gas force, or even none if totally worn).

Over a long time (and when the damper is worn out) the gas inside the damper that creates that force will leak and you're right that the shaft won't extend back out unless pulled.
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      02-19-2020, 01:06 PM   #24
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I agree. I think we were saying the same thing in different ways.
In that case it's a simple explanation.
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      02-19-2020, 03:31 PM   #25
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Quote:
Originally Posted by FaRKle! View Post
Over a long time (and when the damper is worn out) the gas inside the damper that creates that force will leak and you're right that the shaft won't extend back out unless pulled.
How often have you seen this happen to a Bilstein?
Anyone?

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      07-10-2021, 05:56 PM   #26
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How many miles does it takes for the B6's to fully settle.
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      07-15-2021, 01:37 AM   #27
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Quote:
Originally Posted by M4UFO View Post
How many miles does it takes for the B6's to fully settle.
Should be a few weeks at most. Then its the slow steady decline until replacement

Mine settled after a few back and forth commutes to work (250 miles or so).
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      07-25-2021, 11:25 AM   #28
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Pretty easy to verify if the change in ride height is a result of the gas pressure or some dimensional change. Measure from the shoulder that the strut rests on in the knuckle, to the spring perch. If that dimension is different, there is your answer.
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      07-26-2021, 09:34 AM   #29
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Quote:
Originally Posted by Gen13 F36 View Post
There so much inconsistencies on the information posted about shock/springs combo. I wish we could have a concise thread for all applicable combo with photo.
I've seen comparisons around, but since content is driven by unpaid volunteers, it can be dated. For me, I create own notes as I pour over forum posts. Yeah, it's a pain but I'm kind of picky so I resign myself to fact an informed purchase is going to take time.

Ultimately forums are repository of experience. Does product X fit on my car? What happened post install? Guy says "Put those struts on my car two weeks ago and it's great" That answers the question of fitment but hard to say if I'd be satisfied with it. Guy says "Put that on my car 2 years and it's feels great" More useful, even if 'feel' is subjective. The second poster is revealing information about reliability and fitment.

Ultimately it'd be great to see a retailer like ECS Tuning, FCP Euro, etc do comparisons but even then, what would they say "This product is terrible but we sell it anyway." Anything they sell, they sell because there is customer for it. Skeletor says "Product X struts and springs shattered my bony a$$ drving down LandMine Alley" but Fat Albert says "Hey, hey, hey feeling a-ok on Jello Pudding Drive". Once you get your list of products, ideally you find users who use their car like you, and see how they reacted to the product.

I do agree with Farkle that there is indeed a lot of hyperbole (aka bullsh*t) but there is treasure among the trash. In fact, it's one reason why I prefer bimmerpost over some other forums. You can find significant useful info. It just takes time.
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Last edited by casualDIYer; 07-26-2021 at 09:42 AM..
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      07-26-2021, 09:56 AM   #30
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Quote:
Originally Posted by thatBimmerBloke
Interesting! FaRKle! , if you check out this post, B6 with stock springs lowered the car about 10mm, while as the height increased for you:
https://f30.bimmerpost.com/forums/sh...3&postcount=11

Now I've no idea how the B8s will alter the ride height of my car, B8s are shorter than B6 In the same thread there are numbers
related to B8 vs B6 length:
https://f30.bimmerpost.com/forums/sh...6&postcount=10

EDIT: Updated links
I though B6 vs B8 was as simple as B6 = OE replacement and B8 = any lowering spring.
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      08-03-2021, 02:26 PM   #31
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Quote:
Originally Posted by casualDIYer View Post
I though B6 vs B8 was as simple as B6 = OE replacement and B8 = any lowering spring.
I think that was the general consensus. I went with coilovers, didn't want to get stuck with a height that I didn't like. There are a few variables in play, springs, wheels/tires. Just by choosing a different tire you can close the wheel gap by about 10mm. I wanted to keep the diameter close to OEM.
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      08-03-2021, 04:35 PM   #32
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Quote:
Originally Posted by casualDIYer View Post
Quote:
Originally Posted by thatBimmerBloke
Interesting! FaRKle! , if you check out this post, B6 with stock springs lowered the car about 10mm, while as the height increased for you:
https://f30.bimmerpost.com/forums/sh...3&postcount=11

Now I've no idea how the B8s will alter the ride height of my car, B8s are shorter than B6 In the same thread there are numbers
related to B8 vs B6 length:
https://f30.bimmerpost.com/forums/sh...6&postcount=10

EDIT: Updated links
I though B6 vs B8 was as simple as B6 = OE replacement and B8 = any lowering spring.
Not quite.

B4 = OEM Replacement.

B6 = HD design, firmer/sportier. Can handle slight lowering but designed for stock springs.

B8 = HD design, firmer/sportier. Designed for lowering springs.

The B6 and B8 are the exact same damper with a different length body.

Source: Bilstein

Last edited by sspade; 08-03-2021 at 06:57 PM..
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      08-03-2021, 06:44 PM   #33
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Quote:
Originally Posted by thatBimmerBloke View Post
I think that was the general consensus. I went with coilovers, didn't want to get stuck with a height that I didn't like. There are a few variables in play, springs, wheels/tires. Just by choosing a different tire you can close the wheel gap by about 10mm. I wanted to keep the diameter close to OEM.
Agreed and well said.

That's why coilovers is the only answer if there is a requirement to either select a precise suspension height or change the height after initial installation.
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      08-03-2021, 08:38 PM   #34
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Quote:
Originally Posted by sspade View Post
Not quite.

B4 = OEM Replacement.

B6 = HD design, firmer/sportier. Can handle slight lowering but designed for stock springs.

B8 = HD design, firmer/sportier. Designed for lowering springs.

The B6 and B8 are the exact same damper with a different length body.

Source: Bilstein
What’s HD? I assume B6 costs a bit more than B4? How about ride quality?
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      08-03-2021, 09:19 PM   #35
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Quote:
Originally Posted by gameson View Post
What’s HD? I assume B6 costs a bit more than B4? How about ride quality?
B6 shocks are valved about 20% firmer than OEM shocks, according to the source below. The best source of course is Bilstein.

https://www.potn.co.uk/bilstein-range-explained/

While the ride quality can be subject to interpretation, B6 shocks will noticeably improve cornering ability and reduce body roll.
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      08-05-2021, 02:32 AM   #36
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Just installed B4 m-sport shocks paired with H&R Super sports, and they definitely raised the ride height slightly as well compared to stock shocks.

Had B8 shocks on my last car an noticed the same thing, so seems it's not only a BMW thing.
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