[HighlandPete]

Originally Posted by tiberiuenache

I believe that the issue is from tyre thread/compound/XL as on some types of asphalts the car is whisper quiet, even on +60mph higher speed than on bad asphalt.

Tyres do seem to be the sound 'generator', when you can be whisper quiet on good asphalt. It's the experience with all tyres, to different degrees.

My question, why is the tyre road noise different to what we are used to on various surfaces? Has to be the 'pathway' to the cabin.

F40 suffering the same unusual tyre noise?

[tiberiuenache]

Yes F40 seems to have same issue. Altho I still do not get it why the noise is softer and more normal (bearable) with my 16" Winter tyer and ugly rims ? And with the 17" brand new Michelin Primacy 4 ( Same with the OEMs Goodyear Eagle F1 As3) the noise is higher?

A good read below. Might be also the rims model too.

https://global.honda/innovation/tech...cturebook.html

[HighlandPete]

Originally Posted by Liamjay

Mines a staggered set up too albeit 18”.

Judging by your signature, you’ve owned quite a few previous BMW’s too and I’m guessing like me, there’s been no sound like this on the previous which you would consider ‘road noise’.

At last some seat time in a G20. I've been driving a G20 318d M-Sport for a couple of days, driven about 190 miles on all types of road surfaces.

My observation, there is something about how the car is built/insulated that gives a different sort of road noise than previous BMWs.

In my 535i, tyre noise is felt "all around the car", as it were. In the G20 in some situations according to the road surface, it seems to concentrate a different type of noise to the passenger front. It sounds to my ears, as if it is in the front passenger footwell. Weird!

My honest opinion, there is nothing mechanically wrong, as the car can be near silent at a wide range of speeds, on surfaces where the tyres don't generate much noise. Definitely involves the tyres. I was on Pirelli P7, 18" staggered set. M-sport suspension.

If this is the issue many have highlighted, I don't see it as anything more than an unusual tyre/road noise. If it is this concentrated sound, I can see why Tech's are saying 'road noise'.

[pmgoliv]

Originally Posted by HighlandPete

At last some seat time in a G20. I've been driving a G20 318d M-Sport for a couple of days, driven about 190 miles on all types of road surfaces.

My observation, there is something about how the car is built/insulated that gives a different sort of road noise than previous BMWs.

In my 535i, tyre noise is felt "all around the car", as it were. In the G20 in some situations according to the road surface, it seems to concentrate a different type of noise to the passenger front. It sounds to my ears, as if it is in the front passenger footwell. Weird!

My honest opinion, there is nothing mechanically wrong, as the car can be near silent at a wide range of speeds, on surfaces where the tyres don't generate much noise. Definitely involves the tyres. I was on Pirelli P7, 18" staggered set. M-sport suspension.

If this is the issue many have highlighted, I don't see it as anything more than an unusual tyre/road noise. If it is this concentrated sound, I can see why Tech's are saying 'road noise'.

Totally agree with your analysis.

I came from a E61 530d and road noise was "all over the place". Much of it appear to come from the rear axle.
In the G21 it really appears to enter into the cabin in the front passenger side. I totally confirm this.

As I mentioned previously, one of the tests made in my car was to switch my wheels (19'' with Bridgestone Turanza RFT) with the wheels of a different car (18'', no idea which tires).
The noise was there but it was noticeably lower tone.

[radoslavp]

I'd like to leave this thread on the X5 forums here:
https://g05.bimmerpost.com/forums/sh...1698738&page=8

Could it be that G20/G21 chassis is plagued by the same design issue - where the cure, the "vibration absorber" is not available as an option at all ?

[tiberiuenache]

Originally Posted by radoslavp

I'd like to leave this thread on the X5 forums here:
https://g05.bimmerpost.com/forums/sh...1698738&page=8

Could it be that G20/G21 chassis is plagued by the same design issue - where the cure, the "vibration absorber" is not available as an option at all ?

Huh...this is not good, but looks like is a engineering flaw somewhere with these new BMW. I was testing an X5 the other day and noticed that it has more tire noise than my old E60 .

Also seems that for 1 series F40 diesel versions it is a vibration absorber (230HZ it says) on rear axle, but not for gasoline ones. Maybe this is the issue, I'll check with my dealer.

[HighlandPete]

Originally Posted by tiberiuenache

Also seems that for 1 series F40 diesel versions it is a vibration absorber (230HZ it says) on rear axle, but not for gasoline ones. Maybe this is the issue, I'll check with my dealer.

BMW have been fitting frequency vibration absorbers on rear subframes and diffs, for many a year. Depends on specification and drivetrain. I recall an LCI E61 535d I had for a week, having one on the rear subframe.

[MosquitoLT]

Hi all,

Big update - my car was fitted by the dealer with M Performance Accessory Brakes in the front.

The rotor is 100% the last one in this post:

https://www.bimmerworld.com/About-Us...rakes-G20-G22/

Not sure about the caliper though, because mine is blue-colored.

Wheels are 18inch, and brakes fill the area completely.

The annoying grinding sound seems to be gone. Have to go to a silent area with good tarmac to confirm, but now I am 95% positive that this was a solution. I will confirm this shortly.

Brakes feel a little numb, but I guess it needs some more break-in.

[HighlandPete]

Originally Posted by MosquitoLT

The annoying grinding sound seems to be gone. Have to go to a silent area with good tarmac to confirm, but now I am 95% positive that this was a solution. I will confirm this shortly.

What's the thinking behind this change? The mass of larger discs damping out some of the vibrations/sounds...?

[McKrill]

As earlier posted the larger rotors/calipers were also fitted to my car and initially I felt there was a slight improvement but still not good but recently it has become unbearable again. Perfect on smooth, newly laid, asphalt but horrible on normal (Swedish) tarmac.

Are your new rotors dimpled and spotted? Mine are not.

Regardless, it clearly states 19" wheels are required with the 374 mm rotors.

If this is true I will have another issue with BMW since they have promised my 18" winter rims will fit (which I doubt since it is already extremely tight with my summer 19").

I guess we'll see in a couple of months time when winter arrives.

This is so sad on an otherwise very nice vehicle...

[MosquitoLT]

My new rotors are dimpled/spotted - attaching the picture.

[greekcs]

So this confirms the larger rotors fit behind 790M wheels. Good to know. I'm curious to see what the spacing is between the caliper and the barrel, mainly to prevent stones from getting lodged and wearing down the wheel.

[McKrill]

Is there any site with information on rim inner diameter measures?

I have the 793i 19" inch summer rims and Rial X10 winter rims (8x18 5/112 ET30).

Of course especially interested in the comparison between the 790M's and my Rials...

[HighlandPete]

Originally Posted by McKrill

Perfect on smooth, newly laid, asphalt but horrible on normal (Swedish) tarmac..

At least that proves it is not a mechanical fault. It is a generated noise from the road, which isn't supressed some way.

[HighlandPete]

Originally Posted by McKrill

Is there any site with information on rim inner diameter measures?

I have the 793i 19" inch summer rims and Rial X10 winter rims (8x18 5/112 ET30).

Of course especially interested in the comparison between the 790M's and my Rials...

Remember some aftermarket rims will have different internal dimensions (and forms) than OE rims. Not easy to know if they will clear the brakes without trying them.

[pmgoliv]

Thanks for the update.

Interesting to know that the larger brakes fit on the 18'' standard wheels. BMW claimed that 19'' were needed.

But the most important question is: can you confirm a noticeable improvement in the grinding noise?
Second most important question: did BMW offered this upgrade at no cost?

Thanks.

[MosquitoLT]

Hi,

so I drove around 700km in all speeds with the new brakes. I can firmly say that the annoying noise is gone. Changed now to winter tyres, the sound didn't come back.

But in general noise from tyres in this car is very noticeable, insulation is poor.

Dealer in Lithuania replaced the brakes free of charge.

The gap between caliper and brakes is worrying, but i really dont want to change to 19inch wheels, because the car is already very firm.

[McKrill]

My 18" inch wheels fit despite the new larger brakes :-)

And, when I was in for the test mounting a technical bulletin was performed.

Rivets were installed to better secure the front wheel housing fenders.

This might be placebo but I'm imagining the noise has become a little subdued...

Have searched the net but cannot find any additional information why this was done.

Technical bulletin number 10041090200.

Anyone with info?

[Yossi123]

Could someone please post the content of this bulletin?
And is fitting large brakes now a BMW approved procedure for this issue or just a courtesy/good will of the dealer?

[McKrill]

The bulletin is performed on certain vehicles due to risk of wear, paint damage and in the longer run corrosion on the painted panels behind the wheel housing fenders.

I.e. nothing to do with the noise and, in my case, probably just imagination/placebo.

[Kazuya1373]

Hey guys. I had the same issue with noise on bad roads. After some digging i found that part nr. 31106891829, Vibration absorber spring strut
150HZ / 220HZ,is missing from front suspension. Part is for cars with msport suspension and run flat tire functionality.
I have standard suspension with runflat tires and that part was missing.
After installing part on both suspension struts, i have to say, noise is gone. I can still hear when transition from good to bad asphalt is happening, but now is much more smooth and less noisier.

Part nr. 8 from link. http://a.realoem.com/bmw/enUS/showpa...diagId=31_1557

[erawamai]

Originally Posted by Liamjay

That is exactly the noise!

That's a weird noise.

I have a March 2020 330i M Sport Adaptive Munich built.

I confirm I've never had that noise (but I have other noises!).