[usc335]

PROBLEM SOLVED (8/8/2023): The details are in post #24. A quick summary is the noise was from excessive bushing wear in my Ohlins front struts. Ohlins replaced the bushings under warranty. I re-installed my Ohlins front struts today and the noise is gone!
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I need some advice on whether the front suspension clunking I have is possibly from my Ohlins R&T struts or steering rack. Please weigh in.

Background: I have a 2021 M2C purchased new in May 2021. I purchased and installed Ohlins Road & Track coilovers (BMS MR40) in October 2021 with 2600 miles on the odometer. In January of 2023 (about 15 months later), I started to hear a clunking/knocking noise from the front suspension or steering rack going over small bumps at slow speeds when the car is warm with 12,000 miles on the odometer. When the car is cold it is barely perceptible or not at all – it only happens after the car warms up (I typically have to drive the car for about 20 minutes before it starts). I also have a creaking noise when I turn the steering wheel back and forth (about 45 degrees left and right) that comes and goes – I’m not sure if it’s related or not.

In the video below, the first 7 seconds are the clunking/knocking sound as I roll over a slightly bumpy road. From 8 to 14 seconds, that is the creaking noise as I turn the steering wheel left and right:
https://youtube.com/shorts/0zMbpWfhhv8

Although the following videos aren’t my car, but they sound exactly like what I’m experiencing (these videos are better than the one I took of my own car):
https://f80.bimmerpost.com/forums/sh...6&postcount=56
https://f87.bimmerpost.com/forums/sh...&postcount=113

My car isn’t too low – it’s set at 600mm front and 605mm rear. I also have Titan 7 T-S5 wheels (Front = 19 x 9.5 ET27 with Michelin PS4S 255/35-19 tires) with 5mm Turner spacers (w/ integrated hub extender) so the tire clears the strut.

I searched though Bimmerpost and have already checked the strut nut torque (they were fine) and replaced the front strut pinch bolts and nuts torqued to 41 ft-lb (with anti-seize on the mating surfaces only (not the threads) to eliminate the possibility of the clicking noise that many people experience). I’m thinking it’s one of two things:
(1) The steering rack gear bolt (Racer20's deep dive into the strut clunk):
https://f80.bimmerpost.com/forums/sh....php?t=1637057

(2) Ohlins R&T Bushings (Ohlins knocking):
https://f87.bimmerpost.com/forums/sh...2&postcount=90

I’m still under warranty so I took the car to the dealership, but they could not find anything. Unfortunately, I took it to the dealership in March and it happened to be a cold week (even for California), so they could not duplicate it. I want to make sure it’s not my Ohlins before taking it back. I’d rather not spend the money to have a shop put my stock suspension back on just to diagnose the problem if it’s the steering rack. But, I'll do it if it's the only way to isolate it.

Does anyone have any suggestions on how to isolate where the noise is coming from? Thank you.

[WedgeSalad]

Are you running any camber plates?

[usc335]

Originally Posted by WedgeSalad

Are you running any camber plates?

No.

[Jakef100]

Im currently experiencing exactly the same issues apart from i have Millway camber plates. Im hoping its not free play in the strut itself. Currently replacing everything other than the strut itself to see if i can eliminate. Its got to the point when driving slow speeds i have no confidence in the steering with the feedback i get through the wheel.

[Rub1con76]

I have exactly the same problem.
Most of the time the car has to be driven for a while before it occurs. I have this problem now for over a year and took ik multiple times to different shops inclusief bmw dealerships and tuner who installed the ohlins. Nothing to find …..

Even after a year I can’t trigger the sound when I am at a shop . So they don’t hear the sound like I hear it at home on my driveway mostly

[atlas]

I think it's the OEM top mounts not playing nice with the coilover. I had a similar situation with JRZ RS2, which I installed with OEM top mounts. A year or two after install, knocking started which turned to into clunking.

My mechanic checked it over several times, and JRZ even replaced the front struts but the issue remained.

Finally JRZ replaced my entire setup with JRZ RS2 Pros, which included JRZ top mounts. Problem disappeared. At the same time I also had them replace all the one time use bolts.

[ZM2]

Originally Posted by atlas

I think it's the OEM top mounts not playing nice with the coilover. I had a similar situation with JRZ RS2, which I installed with OEM top mounts. A year or two after install, knocking started which turned to into clunking.

My mechanic checked it over several times, and JRZ even replaced the front struts but the issue remained.

Finally JRZ replaced my entire setup with JRZ RS2 Pros, which included JRZ top mounts. Problem disappeared. At the same time I also had them replace all the one time use bolts.

Any idea if new OEM top mounts would have fixed this?

[ddnmkun]

Have you checked the sway bar end link tighten up to torque spec? The first time I did my own installation and didn’t have the correct tool to dial in the bolts and ended up a little lose and created clunking sound.

[ThreeStripes]

Had a clunk coming from the front suspension after some miles/track days on mine. Ended up being the lower ball joint on the FR coming loose. Got it tightened up and the clunk is gone and everything feels solid again.

TC Kline kit with Bimmerworld monoball thrust arm bushings for reference.

My wrench said he had another F82 M4 customer on MCS that had the same issue and fix.

[omasou]

Originally Posted by ddnmkun

Have you checked the sway bar end link tighten up to torque spec? The first time I did my own installation and didn’t have the correct tool to dial in the bolts and ended up a little lose and created clunking sound.

+1

[allinon72]

The suspension on the F8x platform is VERY sensitive to torque specs, especially the top bolt. That is the first thing I would check. The other unfortunate thing is OEM top mounts are just kinda junk and sometimes start to make noise as soon as you disturb them (i.e. installing a new coilover).

[doughboy]

ARB / sway bar drop links if adjustable are prone to coming loose and knocking under light bumps straight ahead, loaded in corners it will stop as ARB in under pressure.

[HP Autosport]

Originally Posted by allinon72

The suspension on the F8x platform is VERY sensitive to torque specs, especially the top bolt. That is the first thing I would check. The other unfortunate thing is OEM top mounts are just kinda junk and sometimes start to make noise as soon as you disturb them (i.e. installing a new coilover).

We often go straight to camber plates or recommend new OE top mounts for in-house installs. Those plastic bearing races just don't hold up at all.

[usc335]

Originally Posted by HP Autosport

We often go straight to camber plates or recommend new OE top mounts for in-house installs. Those plastic bearing races just don't hold up at all.

Thanks for the advice. So you think camber plates are actually less noisy than OE top mounts? Which camber plates do you recommend and which do you think are the quietest? I’m less interested in running aggressive camber than wanting something quiet.

[Sequence_]

Originally Posted by usc335

Thanks for the advice. So you think camber plates are actually less noisy than OE top mounts? Which camber plates do you recommend and which do you think are the quietest? I’m less interested in running aggressive camber than wanting something quiet.

Any camber plate is going to be noisier than oem as they all lack a big chunk of rubber like the standard. Street millway is pretty dammn quiet. a little more tire noise etc no clunking though.

[atlas]

Originally Posted by ZM2

Any idea if new OEM top mounts would have fixed this?

It's possible - the problem did develop over time. I might take photos of them and put them up here to see if anyone can see an issue.

[usc335]

Originally Posted by atlas

It's possible - the problem did develop over time. I might take photos of them and put them up here to see if anyone can see an issue.

My problem occurred over time. It took about 9,500 miles for the clunk to develop. I called Ohlins and they think it might be the strut bushing issue. I'm having the struts removed next week so I can ship them back to Ohlins for bushing replacement if that's what it is. I'll be putting my stock struts back on, so that'll be the first test to see if it goes away. I'll take a look at the top mounts as well. I'll report back as things progress...

[ZM2]

Originally Posted by Sequence_

Any camber plate is going to be noisier than oem as they all lack a big chunk of rubber like the standard. Street millway is pretty dammn quiet. a little more tire noise etc no clunking though.

Aren't they limited in how much negative camber you can adjust into them?

[Sequence_]

Originally Posted by ZM2

Aren't they limited in how much negative camber you can adjust into them?

Still reaches a max of -3.2 which is plenty IMO.

[David.m]

Originally Posted by Rub1con76

I have exactly the same problem.
Most of the time the car has to be driven for a while before it occurs. I have this problem now for over a year and took ik multiple times to different shops inclusief bmw dealerships and tuner who installed the ohlins. Nothing to find …..

Even after a year I can’t trigger the sound when I am at a shop . So they don’t hear the sound like I hear it at home on my driveway mostly

Almost certainly it's the strut bushing shown here
https://f87.bimmerpost.com/forums/sh...2&postcount=69

I had the knocking early on, the bushings were replaced under warranty and knocking immediately gone (I also have Millway Street plates). About 45+K km later the knocking returned, only very faintly, but worsened/got louder over time plus happened from cold rather than just after a drive. There was a change in importer/distributor here which caused a delay for parts but I eventually had the bushings replaced again & like before the knocking went (I've also had the Ohlins serviced, initially the bushings weren't changed and the knocking remained, went back for the bushing change & knock immediately gone).
Sadly after 4K km the knocking is back, I think accelerated by a track day as it was loud driving in the paddock after 20min sessions I'm speaking with the shop that replaced the bushings, wondering if they were supplied the problematic version.

[David.m]

Originally Posted by ZM2

Aren't they limited in how much negative camber you can adjust into them?

I'm at the stock Ohlins ride height (10mm lower than oem), have -3.5 camber with the Millway Street plates, there is maybe 1-2mm of adjustment left.

[usc335]

UPDATE: I removed my front Ohlins Coilovers and replaced them with my stock setup. The noise is now completely gone. I shipped the struts to Ohlins today and I will report back when I get them back and re-install them.