Suspension/Ride Height Thread

E28 technical advice asked and given! Troubleshooting, modifications and more.
Nebraska_e28
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Post by Nebraska_e28 »

theseeker411 wrote:
bmwm3n528 wrote:C.J....Hope you don't mind...



Bavarian Autosport springs
17x8"? s32s/s32 Replicas?
Yeah, I don't mind. But the wheels are actually 18X8 style 32 replicas. Sold those and it's now on 16X8 BBS RSs.
CJ, do you have any updated pics with the RSs??
Nebraska_e28
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Post by Nebraska_e28 »

bump. Calling CJ
fbr
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Post by fbr »

Racing Dynamics Greens
Bilstein Sports
Remotec 16x8 +20
http://imageshack.us/photo/my-images/651/e28q.jpg
cek
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Post by cek »

Doing wheel/tire research found this thread. Thought I'd post some before/after pics & specs.

Model/Motor: '87 535is/B34

Before:
Springs: Stock
Shocks/Struts: Bilstein HD
Other Suspension modifications: None:
Wheel/Tire size: Style 8, 16x7.5" ET15 225/50-16
Image

After:
Springs: H&R
Shocks/Structs Bilstein Sport, K-Mac Stage 1 front camber plate, K-Mac rear camber kit
Rear shocks on lowest spring perch.
Image

After (try #2):
Springs: H&R
Shocks/Structs Bilstein Sport, K-Mac Stage 1 front camber plate, K-Mac rear camber kit
Rear shocks on highest spring perch.
Image
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Re: Suspension/Ride Height Thread

Post by cek »

Let's continue this. First what Bentley says:

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16" rims would be .5" or 13mm greater, so

Front: 589±10mm (23±3/8")
Rear: 527±10mm (20 3/4±3/8")

The difference between these is: 62mm (1.6"). Thus, in general, the front fender measurement should be about 1.5" more than the rear, in order to have the Bentley (Factory?) suggested rake. The smaller the difference between front & rear equates to more rake, which is counter-intuitive at first blush until you remember the front fender lip is higher than the rear.

Try #3 on Vlad. Previous posts were with M30B34 and K-Mac rear camber kit. Now with M30B35 and IE adjustable toe/camber kit on rear. Still with K-Mac up front and Billie Sports all around.

Front: 560mm
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Rear: 549mm
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Difference: 21mm

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Conclusion: Vlad should have less rake. About 20-30mm lower in rear, technically. Right?

Regardless, I love the way it looks and drives so this is all academic.
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Re: Suspension/Ride Height Thread

Post by cek »

Got Maytag back from being aligned:

Front: 568mm
Image

Rear: 545mm
Image

Difference: 23mm
Mike W.
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Re: Suspension/Ride Height Thread

Post by Mike W. »

Wow, cool metric tape measure Charlie, where did you find that???

I forget where I read it, it was some time ago, but the best way of measuring I've ever heard about is from the center of the hub to the bottom of the fender arch. That takes tires and wheels completely out of the equation and in essence just measures springs. You can have 14" wheels, or 19" wheels, and it will take all that out of it and how far the wheels/tires make it off the ground and tell you how much the springs changed things. Brilliance, but outside of where I read it and my writings it seems to be just as quirky as I am. :cool:
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Re: Suspension/Ride Height Thread

Post by cek »

Mike W. wrote:Wow, cool metric tape measure Charlie, where did you find that???
Our resident metric-Nazi, Mr. Grau gave it to me for Christmas. I figure now that I have it I gotta use it.

Regarding measurement technique, my suspicion is "it's all relative" and what you really want to know are:

- Is it even (or appropriately even given driver weight) side-to-side
- Is the rake (back-to-front) not obnoxious one way or another
- Is it loooow, 4x4, or "just right"

None of these really require the same measuring technique car-to-car. We have Bentley as a baseline for what a stock setup should be, and it appears from an absolute height perspective, that's a lot higher than most E28 enthusiasts are willing to go. In addition the Bentley prescribed rake seems non-existent (more below).

Here's pics I took today of Maytag. I re-did my measuring because I really wasn't very careful last night for the pics above.
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Left Front: 568mm,
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Left Rear: 545mm
Image

Right Front: 565mm
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Right Rear: 538mm
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Summary:
Left Front: 568mm, Left Rear: 545mm (23mm)
Right Front: 565mm, Right Rear: 538mm (17mm)

Avg: 567mm F, 542mm R

Recall from above, stock should be (with 16" wheels):
Front: 589±10mm (23±3/8")
Rear: 527±10mm (20 3/4±3/8")
Diff front to rear: 62mm

Thus Maytag is about 22mm (.9") lower than stock in the front and 15mm (.6") HIGHER than stock in the rear.

FWIW, I measured bottom of rockers as well. Front was 185mm and rear was 210mm. So a 25mm rake rear-to-front (1"), which is why I believe the Bentley (factory?) spec is for there to be NO rake.
sansibar
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Re: Suspension/Ride Height Thread

Post by sansibar »

Image
euro M535i DC71 3,4 ltr
H&R coilovers screwed on highest position
7x18 ET20 RC090 225/45R17 PSS on all four corners
10mm spacers on front axle
rear M5 swaybar
LCA/UCA combiantion of moosehead and E31
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Re: Suspension/Ride Height Thread

Post by tschultz »

cek wrote: Summary:
Left Front: 568mm, Left Rear: 545mm (23mm)
Right Front: 565mm, Right Rear: 538mm (17mm)

Avg: 567mm F, 542mm R

Recall from above, stock should be (with 16" wheels):
Front: 589±10mm (23±3/8")
Rear: 527±10mm (20 3/4±3/8")
Diff front to rear: 62mm

Thus Maytag is about 22mm (.9") lower than stock in the front and 15mm (.6") HIGHER than stock in the rear.

FWIW, I measured bottom of rockers as well. Front was 185mm and rear was 210mm. So a 25mm rake rear-to-front (1"), which is why I believe the Bentley (factory?) spec is for there to be NO rake.

Great detail here Charlie.
I measured my car after changing rear springs.

Front is about the same as you at 577mm, rear is currently at 560mm. We will see if they settle at all, but I suspect the height is being partially influenced by my larger sway bar. Even though it has some rake, is looking about right to me (eibachs gave me a saggy bottom).
EDIT: Rear settled to 550mm average. So my rake is very similar to Charlie's.
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Re: Suspension/Ride Height Thread

Post by cek »

Anyone else do this and care to post their findings?

I'm re-dialing in Minerva right now that I've got the right springs for the H&R coil-over setup finally...
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Re: Suspension/Ride Height Thread

Post by cek »

Update on Maytag:

This is with Bilstein Sport struts (6 perch) and Spax springs:

Front Left: 560mm
Image
Front Right: 567mm
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Rear Left: 523mm
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Rear Right: 533mm
Image

Last time I measured (Jan 2015 with the BC Racing Coil Overs) she was:
Front Left: 568mm
Front Right: 565mm
Rear Left : 545mm
Rear Right: 538mm

I hate how low the rear looks now. I'm shooting for

Front: 570mm
Rear: 550mm
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Re: Suspension/Ride Height Thread

Post by tschultz »

I did not like the saggy bottom and hence why I used some taller springs on Burt the 535is.

I'll see if I can remeasure soon here since springs have been on the car for about two years. Still they were taller than the Eibachs and maybe slightly taller than stock, but the 550mm seems about right to my eye.

Image
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Re: Suspension/Ride Height Thread

Post by cek »

Minerva is back with new springs. The kit:

H&R Coilover 28808-9 kit
Front: HRF200060 springs (200mm length, 60N-Rate), ZF-100-12.5 tender springs
Rear: HRF250060 springs (250mm length, 60N rate) ZF060-025 tender springs

Front: 558mm L / 559mm R
Rear: 545mm L / 545mm L

I think that's about perfect.

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topher800
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Re: Suspension/Ride Height Thread

Post by topher800 »

I am running about 553 front and 530 rear.

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