[Pbdeed]

Hello,

This weekend I went to a track and I´ve heard a noise in both left and right front wheels when I turn right or left respectively (the wheel with most of the weight).

The noise just appears after some driving, not first laps, like when some part gets temperature (don´t know if brakes, tyres, ...). it has to be a closed turn (for example, a roundabout) with significant speed, just to load weight in the outside of the car.

Its a noise only heard with windows down (it´s not heard inside the car with windows closed). And it is not a continuous noise, its like a rattle and its increased as I turn more.

Just to give more context I have TS+LCAs , does any one had a similar problem? As its in both sides and when suspension is compressed it seems that maybe TS+LCAs changed geometry and something is touching. It could be the metal part behind the rotors?

I also have Ferodo DS2500 (this pads dont have a counterweight in the back of the pad as stock ones have). Just in case it could matter.

In a workshop they didnt´see anything relevant.

I know its difficutd to identify the cause with this description but maybe someone had a similar problem.

Regards

[Pbdeed]

I was be able to extract and filter sound from a recording someone took from the padook.

https://vocaroo.com/dH3H0270pbh

It´s like the "jingle" sound at 0:01.

[Maynard]

look for signs of tire rubbing, especially if on nonstandard wheel/tire sizes. LCA does move wheels off-center in the wheelwell (I think they are prone to rub on the inner fender liner?).

[Pbdeed]

Its a metalic intermitent sound, it doest sound to tire rubbing (i use standard wheels amd tyres)

[Pbdeed]

I´ve tried this morning with stock front brake pads and rattle when turning is still there .

We have checked all the joints and so and everything seems ok.

I wonder if:

- Just LCA + TS geometry modifcation could generate clearance issues (stock wheels and tyres), and some parts are touching when load is on one side of the car.

- Maybe the metal plate behind brake rotors is touching something when rolling.

It is not a continuous noise, its more like a metalic rattle (like with every wheel spin) and when turning hard, for example in a roundabout.

Anyone experiencing something similar? I´m getting crazy

[accs]

It sounds similar to a noise I had when a weight on my rear wheel was hitting the brake pad weights.

[Pbdeed]

Originally Posted by RyonC

It sounds similar to a noise I had when a weight on my rear wheel was hitting the brake pad weights.

The DS2500 have no weight. I changed to stock pads in front wheels, as it is where the noise comes from.

I also tested removing the metal plate behind the rotor (the protection) and the noise is still there.

It appears after some hard turns (i did some roundabouts and tyres squealing in some of them), but no in the first ones, and after that every time I have to turn the steering wheel like 60° with some speed,

I´m even thinking in installing the stock TS+LCAs to see if this is the "problem" and the rattle dissapears, but I don´t know if it really makes sense as the sympthoms , from my little understanding, are not related to TS+LCAs (and the cost of installing the old stuff and then the TS+LCAs again).

I would appreciate any help or comment from other TS+LCAs users.

[Pbdeed]

Originally Posted by RyonC

It sounds similar to a noise I had when a weight on my rear wheel was hitting the brake pad weights.

What was exactly the problem? how did you solve it?

Thank you

[Pbdeed]

I found this post which is the exactly same problem:

https://www.2addicts.com/forums/show...php?p=23721033


Do you know if there is that Service Bulletin?

[pikcachu]

usually just re-torquing the wheels fixes it...it can also be the brake shield

[Sonertial]

Originally Posted by pikcachu

usually just re-torquing the wheels fixes it...it can also be the brake shield

For me, torquing the wheels has no or little effect.

I have my own theory about this. I don't think it's wheel bolt torque, or micro slipping of hub surfaces. Here's my chain of events and my reasoning.

I recently discovered that it is affected by tyre pressure.

Both myself (M240i) and a colleague (M2) experience this ticking sound. We both only get it with summer tyres, he has had the hubs cleaned and friction plates installed according to the service bulletin. He still hears it occasionally, a year or so later.

For me it started (or was noticed) after a hard track session. I had mounted Michelin Pilot Sport Cup 2 tyres a couple of years ago, with a 10mm front spacer and noticed the sound when leaving the track, noted it, but didn't think much of it. I pumped up the tyres to street pressure for the ride home and completely forgot about it.

I run at ~2 (30 psi) bar on track, ~2.4bar (35psi) for daily driving.

While testing and bedding new brakes the next summer, I reduced the tyre pressure to boost grip in some warm weather. The ticking sound was very apparent and triggered a frenzy of testing, torquing, and arguments with the dealership which resulted in no conclusion. I could not figure it out. I did not make the connection with tyre pressure.

Around that time I mounted M2 LCAs, (only, no TS) removing the spacers. Still ticking. I drove for a few weeks before switching to winter tyres. The ticking sound disappeared.

I had at this stage gotten used to it.

This year, when I switched back to PS2s for summer, I was not even thinking about the sound. It was completely gone.

The place where I store my tyres over winter had pumped them up to 2.6 (38psi) bar cold. I think they do this for fuel economy reasons. I saw this when I reset the tyre monitor, but could not be bothered to reduce the pressure, I only had short trips to do.

As the weather improved and I got more focused on driving again, I finally dropped the pressure to a more appropriate 2.2bar cold.

On the very first corner, tick tick tick tick tick tick tick tick...

My purely speculative theory is that it is related to front grip. I think the DSC or ABS unit is activating when the wheels turn at different rates. When the grip is low, like with thinner winter tyres, or the tyre patch is smaller when the tyre is pumped up, I don't think the DSC/ABS unit needs to work as hard if at all. The ticking sound reminds me of when you trigger ABS and lock up the front tyres, it pulses at a similar frequency. My guess is that the DSC unit is doing something with the brake lines, similar to the way the brakes are pretensioned if you let off the gas suddenly.

There might be a way to affect this with coding thinking about it.

That's how I see it. Not wanting to spread misinformation, but this issue quite literally has no known solution, service bulletin or not, so I don't feel bad throwing out another hypothesis.

[Pbdeed]

This is happening to me with DSC off too (in track) so DSC unit should be doing nothing about it.

[Pbdeed]

Originally Posted by pikcachu

usually just re-torquing the wheels fixes it...it can also be the brake shield

I´ve checked, recheked all of this. In fact, the brake shield you is the metalic plate I refered to in a previous post.

[Sonertial]

Originally Posted by Pbdeed

This is happening to me with DSC off too (in track) so DSC unit should be doing nothing about it.

Yes, me too. I am not talking about DSC-off mode, I am talking about the DSC unit.

It still does things even in DSC off mode. Brake Fading Compensation, Brake Standby, Hydraulic Brake Assist, some discussion of this here:
https://www.2addicts.com/forums/show....php?t=1231483

The DSC pulse generator may still be active, even if it's not actually applying hydraulic pressure.

https://www.realoem.com/bmw/enUS/sho...diagId=34_2126

https://www.realoem.com/bmw/enUS/sho...54#34526791223

[Pbdeed]

They applied the solution in the Service Bulletin and the problem was gone. The solution
was adding a friction plate between brake rotor and bearing:

https://static.nhtsa.gov/odi/tsbs/20...46758-9999.pdf

I´ve tested in a track and everything OK.