Bilstein & H&R Parts - What is correct?

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TimU
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Bilstein & H&R Parts - What is correct?

Post by TimU »

Hi gang,
Help a brother out - I keep flipping and flopping between suspension setups.
I've tried to read as much as I can about the various options, but I'm getting stuck in analysis paralysis.
Help me out of my rabbit hole please?

Car: 1986 635csi Euro (Aussie)
Wheels: 17" Alpina reps
Current Suspension: Factory original.
Car use: Strictly weekend cruising only.

Goals:
- Refresh with modern components while doing a broader overhaul of other suspension components.
- Circa 1" drop from current height to match the new 17" Alpina rims.
- Improved handling, but still a comfortable ride.

Current thinking:
- H&R Springs, part # 50428 (Front & Rear kit)

- Bilstein B6 shocks
Front: 24-006088 / 34-002339 / 34-002292 / 34-002339
Rear: 24-007276 (Shorter rod) / 24-006088 / 24-008020
OR
- Bilstein B8 shocks
Front: 24-006071
Rear: 34-181546

Questions:
1) Bilstein B6 or B8s with the H&R springs? Conflicting reports about a harsh ride with the B8s.
2) Which part numbers are correct? There are so many options listed around the web, I'm struggling to identify the right parts.
3) I've read that B6 rear shock model 24-007276 has a shorter rod to prevent the spring falling out of the perch when the car is up on a hoist. True?
4) Any other feedback?

Thanks in advance.
04/1986 635csi Euro spec
Australian Delivered, RHD
TimU
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Bilstein and H&R Parts - Correct Part Numbers

Post by TimU »

Here's an update with Part Numbers (and I'm happy that it's not just me that's confused)

Springs:
H&R Spring Kits have different part numbers for North America vs Europe.
To suit vehicle: >1982-89 BMW 635CSi E24 (E28 based)
  • North America product: 50428
  • Europe product: 29534-2
The rear springs are the same in both kits.
The front springs of the US part number is about 5 N/mm harder.
Both parts have the same drop, ~30mm / 1.25"
Source: H&R Tech Support via email.

Front Shocks:
  • 34-002339 = Bilstein B6 Front
  • 34-181546 = Bilstein B8 Front
Rear Shocks
  • 24-006088 = Bilstein B6 - 3 Perch rings (Use with caution: Reports of springs dropping of perch at full extension)
  • 24-006071 = Bilstein B8 (Softer) - 6 Perch rings with 160/80 damping parameter
  • 24-007276 = Bilstein B8 (Firmer) - 3 Perch rings with 270/100 damping parameter
The "parameters" are compression and rebound, so the stiffer version would have significantly more compression damping and slightly more rebound damping.

FWIW, most E24 suspension kits use the softer 24-006071 B8's.

Typical pairings:
Bilstein B6 for use with with standard ride height springs (+/-25mm)
Bilstein B8 for use with lowering springs >25mm
  1. Front & Rear B6 shocks with standard springs all around.
  2. Front & Rear B6 shocks with MTech springs all around. (TBC)
  3. Front B6, Rear B8 shocks with H&R springs all around.
  4. Front & Rear B8 shocks with H&R springs all around.
More info about the different rear shock B8's at https://www.mye28.com/viewtopic.php?t=146121
Bilstein now offers a softer rear B8 (160/80 damping), and a stiffer rear B8 (270/100 damping) for our cars (E28).
Their German-language catalog recommends the stiffer version for 535's and the softer version for all other E28.
This recommendation is lost in the English catalog and many "parts house" listings, which adds significantly to the confusion.
Last edited by TimU on Thu Jun 02, 2022 1:26 pm, edited 1 time in total.
04/1986 635csi Euro spec
Australian Delivered, RHD
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Slownrusty
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Re: Bilstein & H&R Parts - What is correct?

Post by Slownrusty »

On my '86 635 (goldie): I am running B8s with BAV springs (very similar to the H&Rs) and very satisfied with the ride.

On my '84 M635 (pumpkin): I am running B8s with H&R springs and also very satisfied with the ride.

B8 rear shocks have a c-clip on the body where you can adjust the height of the spring perch.,,which is a clever feature.
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Sbeaud
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Re: Bilstein & H&R Parts - What is correct?

Post by Sbeaud »

Tim, thanks very much for bringing clarity to a very confusing subject.

Scott
1988 M6
wattsmonkey
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Re: Bilstein & H&R Parts - What is correct?

Post by wattsmonkey »

I just saw this after posting my findings above! Great info here.

Just a quick clarification - standard M635CSi has B6 length shocks with shorter bumpstops.

The importance of the shorter rear bumpstops can't be stressed enough, or you'll be riding on the bumpstops even with the mild drop the M springs give.
"Most of it necessary; all of it enjoyable." LJKS
'84 635CSi, dogleg...itbs and supercharger????? Eaton Mess
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Re: Bilstein & H&R Parts - What is correct?

Post by ByronB »

Are rear bump stops necessary with stock euro springs on an E12 based car when replacing original Boge's with Bilstein B6's? The rear Boge's do not have bump stops, so just wondering if I should add the ones that came with the B6's in or not. Stock (euro) ride heighet. E12-based 2/81 production euro 635.
1981 Euro 635csi Dogleg 5-speed, Recaros, LSD, Sunroof & A/C
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Re: Bilstein & H&R Parts - What is correct?

Post by 1bhp »

Slownrusty wrote: Thu May 26, 2022 12:59 pm On my '86 635 (goldie): I am running B8s with BAV springs (very similar to the H&Rs) and very satisfied with the ride.

On my '84 M635 (pumpkin): I am running B8s with H&R springs and also very satisfied with the ride.

B8 rear shocks have a c-clip on the body where you can adjust the height of the spring perch.,,which is a clever feature.DSC_0010.JPG

DSCN2790.JPG
Any chance you could measure the distance from centre of hub to bottom lip of wing, front and back on either set-up please? 🙏🏼

My front end seems ok, but back is on one of the higher spring perches, so I want to know what to aim for when we drop it to one of the lower ones...

I have B8's with FritzBitz custom springs (i had H&R on there but swapped them out as they left the front end way too low with extra weight of the Highline spec).

Many thanks in advance. BP
London
'89 635csi
'72 914
'96 850R
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Slownrusty
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Re: Bilstein & H&R Parts - What is correct?

Post by Slownrusty »

Sure..I'll pull a tape and let you know.
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Re: Bilstein & H&R Parts - What is correct?

Post by bpoliakoff »

Slownrusty wrote: Thu May 26, 2022 12:59 pm On my '86 635 (goldie): I am running B8s with BAV springs (very similar to the H&Rs) and very satisfied with the ride.
On my '84 M635 (pumpkin): I am running B8s with H&R springs and also very satisfied with the ride.
B8 rear shocks have a c-clip on the body where you can adjust the height of the spring perch.,,which is a clever feature.DSC_0010.JPG
DSCN2790.JPG
I am running Koni oil filled strut inserts up front and Koni gas filled in the rear. H&R springs all around with somewhere around a 1.25-to 1.35 drop and 17" tires. The car rides firm but by no means harsh and sits just right for my taste and by no means looks like a low rider.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
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jps635
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Re: Bilstein & H&R Parts - What is correct?

Post by jps635 »

Sine you’re in Aus you may want to check out Pedders offerings. My setup after some trial and error:

Rear
- Strut mounts
- Bilstein B8’s
- H&R springs
- Kmac adjustable camber kit (stands wheels up)
- Whiteline 19mm?? (can’t recall) sway bar
- Dog-bones - I forget?
- 255/40/17’s on 9” rims at 32psi
- 15mm spacers (retained on wheel mounting face)

Front
- Fixed -ve 0.5 degree (BMW) top mounts
- Bilstein B8’s.
- 3mm spring pads (initially had 9mm)
- Pedders SportsRyder springs - Was the lower of their offerings - the H&R’s sat too high. 
 (See my post from some time ago “springs, springs, springs")
- Bump steer correction strut spacers
- Whiteline 24mm?? sway bar with poly bushes
- IE strut brace
- 235/45/17’s on 8” rims at 34psi
 - 15mm pacers fixed as above

Have Lemforder arms (lower aluminium) with the Meyle HD inserts. PO had poly bushes but they were too hard and deformed

Car sits relatively low, but not too low which I know is subjective. Corners quite flat with good grip, inspiring confidence. Ride is good on good roads but can be harsh if potholes or scabby road surface. If both front wheels hit the same bump or dip at speed, like a bad bridge expansion joint, can be very harsh, but some of our roads are in very poor condition. Perhaps the 9mm spring pads could go back in.
Have Lemforder arms (lower aluminium) with the Meyle HD inserts

If you replace the strut mounts car will settle about 1/4 inch over time.
'85 635csi JPS (RA2-66)
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Re: Bilstein & H&R Parts - What is correct?

Post by 1bhp »

Slownrusty wrote: Tue Jun 06, 2023 1:49 pm Sure..I'll pull a tape and let you know.
Did you ever get chance to measure the rear hubcentre-to-lip distance?
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'89 635csi
'72 914
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