[Juice247]

I swear I'm not crazy. At super low speeds, like 5mph or so, there is a very slight knocking sound from the suspension. You can hear it from time to time at higher speeds, but it's really hard to focus on. I can't get my dealer to hear it or understand what it could be, but I don't hear this particular sound on any of my other cars. Does anyone know what could cause this, so I can point my mechanic in the right direction?? Is there a point that commonly fails on the adaptive suspension?

[FaRKle!]

When does the knocking occur (types of surface features, front or rear, only high speed, ect.)? It's unlikely it's active suspension specific.

[cfm56d7b]

There are no known common M adaptive suspension weak points. The shocks are quite sturdy and have a decent life span - well beyond 50K miles.

Few questions (while acknowledging that remote diagnostics are rarely effective):

- When did the sound start?
- Is there a distinct metal-over-metal pitch or something more dull?
- As FaRKle! indicated earlier: front or rear?

Also - measure the gap between the wheel and the fender. If the gap is substantially different, this is worth investigating. The shock (more probable) or spring (less probable) could be failing.

[frchdragon]

Could also be any suspension part, control arm, sway bar link.
My front M adaptive suspension were leaking badly but were still handling better than the stock F30 suspension, they did make a noise that I thought was a bad ball joint, but it was the shock because the noise went away when I replaced them with Bilsteins B4.

[Juice247]

I have had the car for only 2500 miles of it's 25k miles. It has had this sound for as long as I can remember, but it's really faint so I blamed it on the run flats until I changed them to go-flats and had an alignment done. Now the noise is more clear. It happens over slightly uneven pavement and can be heard best going slowly around a parking lot. It is definitely coming from the front and the sound reminds me of a poorly fitting knuckle or ball joint.

The wheel gap measures 4.875" on all but the front passenger side, where it measures 4.75". This is from the top of the rim to the to of the fender arch on an X-drive car with factory adaptive suspension and springs.

[Skyhigh]

Unrelated, but could you please measure your distance(s) from the centre of the wheel vertically to the arch? Just want to compare...

On-topic: I have the same suspension and have bought the car new. Already at the beginning I heard a knock a few times when going over speed bumps. Not every time and obviously very dependent on the speed (I never go too fast over them). It was a single knock coming from the front, like metal hitting metal. I have not heard it for quite some time now....

[rooosh798]

Originally Posted by Juice247

I swear I'm not crazy. At super low speeds, like 5mph or so, there is a very slight knocking sound from the suspension. You can hear it from time to time at higher speeds, but it's really hard to focus on. I can't get my dealer to hear it or understand what it could be, but I don't hear this particular sound on any of my other cars. Does anyone know what could cause this, so I can point my mechanic in the right direction?? Is there a point that commonly fails on the adaptive suspension?

Does it sound like something is loose? had a similar situation to you recently where low speed bumps would make slight knocking noises. Sounded almost like something was loose in the front suspension and made a very faint sound. My SA at the dealer diagnosed it to be a faulty front strut which was replaced under warranty and solved the issue. Happened on both sides so now I have new 2 new front adaptive suspension struts installed at 35k miles. Try to drive around in sport mode to see if it makes the sound louder. In my case, the stiffer damper settings of sport mode made the noise distinctly audible.

[franky818]

I have the same problem with H&r springs on though ... thinking it's that

[rooosh798]

Originally Posted by franky818

I have the same problem with H&r springs on though ... thinking it's that

There's a bunch of threads on here about aftermarket springs not playing nice with the stock strut top mounts. Maybe that could be your issue.

[Stucks]

I have the same thing with my 17 340i xdrive with adaptive suspension. faint knocking sound at low speeds. had a driver side front strut replaced and the issue was still present. also replaced leaking thrust arms, still present. right side front strut is next thing on the list, as it is leaking a little bit but not sure if its enough to cause the noise. the springs have been stock.

[Uni-Rapide]

Originally Posted by Juice247

I swear I'm not crazy. At super low speeds, like 5mph or so, there is a very slight knocking sound from the suspension. You can hear it from time to time at higher speeds, but it's really hard to focus on. I can't get my dealer to hear it or understand what it could be, but I don't hear this particular sound on any of my other cars. Does anyone know what could cause this, so I can point my mechanic in the right direction?? Is there a point that commonly fails on the adaptive suspension?

How old is your car?
I've heard that early F-series with adaptive suspension had noise/sound issues.
My 340i (10-2018 production) with adaptive suspension is fine, no strange sounds from the suspension

[Juice247]

Originally Posted by Uni-Rapide

How old is your car?
I've heard that early F-series with adaptive suspension had noise/sound issues.
My 340i (10-2018 production) with adaptive suspension is fine, no strange sounds from the suspension

Mine is MY17, 10/16 production, so it's an early LCI. I have an appointment with an Indy in my area to take a drive and a look on Wed so I'll report back!

[Juice247]

So I now have had 3 shops look at this, along with an alignment, and there is nothing wrong. The slight knocking sound is just that this suspension/tire combo is noisier than the stock non-adaptive setup. Crisis averted.

[BurtMacklin]

I had a knocking from the front left at low speeds over almost any type of road surface. Mileage is 69xxx.

I started with-
replacing the steering box bushing- no change
torsion arm- it was leaking/bad but no change
lower control arm and upper strut mount- no change despite the strut mount being utterly shot
strut- this was the culprit. I bought a pair of Bilstein B4 dampers so that I could save a few bucks over oem and I wasn't ready to commit more money for the b6. I'm so much happier driving it as it's been noisy since I bought it used in Feb of this year.

[Shred Sled]

I have a gravel driveway and hear the knocking sound everyday. Seems to be more prevalent in colder temperatures. The sound was there with my 2016 F31 328ix with adaptive and stock springs. Now running Eibach springs and the sound is still there. Dealership could not hear/replicate the sound. I thought I'd seen a thread some time ago with an SIB software fix for the adaptive struts. To me the sound is like shaking dice in cup with your hand over the open end.

[Watsey]

Sorry to contradict some of the replies that state that there's no known problems with the adaptive dampers, but...

To the contrary, there was/is a problem with these units, depending on the age of the car. The adaptive damper valves are known for their opening/closing to not be optimised with the inputs that they are trying to control, which results in a knocking/clunking noise. It's typically heard at low speeds, say up to 20mph.

There is a PUMA case on BMW's systems which (from memory) resulted in a QE (Quality Enhancement) which includes a software update to change the operation of the damper valves.

I had this update applied to my car and it cured the problem. Ironically this only happened after BMW replaced both front adaptive dampers because it couldn't sure the knocking noise.

Of course that's not to say that all knocking noises originate from the adaptive dampers, but it's certainly worth investigating.

[cfm56d7b]

Originally Posted by Watsey

Sorry to contradict some of the replies that state that there's no known problems with the adaptive dampers, but...

To the contrary, there was/is a problem with these units, depending on the age of the car. The adaptive damper valves are known for their opening/closing to not be optimised with the inputs that they are trying to control, which results in a knocking/clunking noise. It's typically heard at low speeds, say up to 20mph.

There is a PUMA case on BMW's systems which (from memory) resulted in a QE (Quality Enhancement) which includes a software update to change the operation of the damper valves.

I had this update applied to my car and it cured the problem. Ironically this only happened after BMW replaced both front adaptive dampers because it couldn't sure the knocking noise.

Of course that's not to say that all knocking noises originate from the adaptive dampers, but it's certainly worth investigating.

Very helpful. By any chance, is the PUMA case number available?

[Watsey]

Originally Posted by cfm56d7b

Very helpful. By any chance, is the PUMA case number available?

I checked my emails and I did ask (2016) the service manager (at the BMW supplying dealership that I used to take my car to) for the PUMA reference/number but he replied to say that he wasn't permitted to disclose it.

His reply does at least confirm that a PUMA case does/did exist on BMW's systems for this issue.

[cfm56d7b]

Originally Posted by Watsey

I checked my emails and I did ask (2016) the service manager (at the BMW supplying dealership that I used to take my car to) for the PUMA reference/number but he replied to say that he wasn't permitted to disclose it.

His reply does at least confirm that a PUMA case does/did exist on BMW's systems for this issue.

Thanks for checking - always appreciated.

[M140_BCS]

Puma GB 62569674-04