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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Suspension | Brakes | Chassis > Mushy suspension



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      07-10-2023, 10:10 AM   #1
gvisockas
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Mushy suspension

Although a similar question has been posted recently, I feel that the problem is elsewhere, hence a new thread.

My suspension feels as if it were made from jello- light, precise steering input does not have an effect. When maneuvering similar to the moose test, it seems as if either the shocks are blown or the whole suspension is shot. Same goes for potholes or other unevenness of the road- lots of deflection to the point that the car feels broken- wheels hitting the pothole seem to stall the car a bit, similar to cow's feet on ice going into separate directions.

I would suspect tire sidewall deflection to be the culprit, but for one, the sidewall isn't that high, second to that, pressure does not seem to have an effect.

My setup:
-New M3 lower control arms;
-New Meyle HD tension struts;
-New shocks (standard TRW);
-SE suspension otherwise;
-225/45 R17 tires;
-Six cyllinder N57 engine;
-Sedan body;

Do all standard suspension setups feel so disconnected?
Are my tires too high?
What would you suggest? I am considering sport struts-springs (ST), 80ShA polyurethane tension strut bushings (I shied away from M3 ones as I felt the solid rubber bushing to be too stiff).

Any input is greatly appreciated.
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      07-10-2023, 11:52 AM   #2
Tambohamilton
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Did you torque the bushing (inboard) ends of the tension struts with the suspension at ride height?
How is the geometry?
Other parts in good condition? Tie rods/ends, top mounts, bump stops, rack?
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      07-10-2023, 01:15 PM   #3
gvisockas
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Since roads get salted where I live, tie rods and end links had to be replaced. Everything else is in order, although I don't suppose bump stops have a great effect on it since suspension is far from bottoming out when this happens.

Top mounts and springs are the only parts that haven't been changed.
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      07-10-2023, 01:41 PM   #4
Hockey7269
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Just a thought...

Have you checked to make sure your strut bars are not bent and tightened correctly. I forgot to tighten mine back up after doing some work once, and the car felt really loose.
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      07-11-2023, 02:17 PM   #5
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Your shocks might be under dampened to your springs
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      07-11-2023, 02:40 PM   #6
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Quote:
Originally Posted by gunnerxq View Post
Your shocks might be under dampened to your springs
How do you pair them properly without buying genuine BMW parts? Reason I ask is that even aftermarket shocks and struts are all listed as fitting nearly all E9x models, but not all E9x models come with the same springs.

I'm dealing with a similar weird possibly under-dampened feeling in my E93. This car has D8 front springs. Bilstein shows the same struts fitting nearly all E9x models, and I know my 330i sedan has the D6 springs up front which are softer. How does the same damper work for two different springs? Or is it a case of "it works" but it's just not optimal?

I even looked at aftermarket kits with struts and springs, and they all use the same "sport" spring for the sedan, coupe, wagon, and convertible.
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      07-11-2023, 06:41 PM   #7
Tambohamilton
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Quote:
Originally Posted by lowrydr310 View Post
How do you pair them properly without buying genuine BMW parts? Reason I ask is that even aftermarket shocks and struts are all listed as fitting nearly all E9x models, but not all E9x models come with the same springs.

I'm dealing with a similar weird possibly under-dampened feeling in my E93. This car has D8 front springs. Bilstein shows the same struts fitting nearly all E9x models, and I know my 330i sedan has the D6 springs up front which are softer. How does the same damper work for two different springs? Or is it a case of "it works" but it's just not optimal?

I even looked at aftermarket kits with struts and springs, and they all use the same "sport" spring for the sedan, coupe, wagon, and convertible.
You're exactly right; it works but it's not ideal. If you want to get a better match, you probably need to go custom tune/adjustable
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      07-11-2023, 07:04 PM   #8
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Quote:
Originally Posted by lowrydr310 View Post
How do you pair them properly without buying genuine BMW parts? Reason I ask is that even aftermarket shocks and struts are all listed as fitting nearly all E9x models, but not all E9x models come with the same springs.

I'm dealing with a similar weird possibly under-dampened feeling in my E93. This car has D8 front springs. Bilstein shows the same struts fitting nearly all E9x models, and I know my 330i sedan has the D6 springs up front which are softer. How does the same damper work for two different springs? Or is it a case of "it works" but it's just not optimal?

I even looked at aftermarket kits with struts and springs, and they all use the same "sport" spring for the sedan, coupe, wagon, and convertible.
You'd have to start with shocks like Koni Yellow. They're the cheapest and the best for adjustability for the price. Not cheap but doable.


But I rechecked your original post. What tires do you run and what PSI?
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      07-11-2023, 09:28 PM   #9
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Quote:
Originally Posted by gunnerxq View Post
You'd have to start with shocks like Koni Yellow. They're the cheapest and the best for adjustability for the price. Not cheap but doable.


But I rechecked your original post. What tires do you run and what PSI?
I don't want to hijack this thread, but I think I posted my tire setup on my post. Brand new Michelin PS4, 225/40-18 front, 255/35-18 rear. 32 front 39 rear to start, but I experimented with all sorts of pressures. 40/40 then lowered gradually.


To the OP here, I'm told some of this mushy feeling might be due to improperly torqued suspension components. Did you feel yours after installation of new suspension components because that's when I first noticed it. I'm leaning toward that but haven't driven the car and haven't inspected and retorqued yet.

In your case it sounds like it could be the steering column u-joint pinch bolt. The do loosen and cause that sloppy disconnected feeling. I'm going to check that on my car too.
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