[spyro512]

Originally Posted by das340i

Have you guys tried replacing the hubs too? I haven't tried this yet but, I am tempted to before I replace the brakes again

F30 320i Msport with brembos 340mm

After 38000Km with the original rotors and pads, it’s started vibrating and I changed rotors and pads as a result: Zimmerman + TRW pads.

After 7000Km aprox. it started vibrating again and I went full nuts: new rotors and new hubs. Worked flawlessly but around 20000Km after… here I am again, vibrations are back.

Can’t be warping, can’t be hubs. I suspect on the calipers now but I’m not sure.

I might go to some pads that have less material transfer such as Ferodo DS2500, but other than that, I am very lost.

[Dynamites]

Originally Posted by spyro512

F30 320i Msport with brembos 340mm

After 38000Km with the original rotors and pads, it’s started vibrating and I changed rotors and pads as a result: Zimmerman + TRW pads.

After 7000Km aprox. it started vibrating again and I went full nuts: new rotors and new hubs. Worked flawlessly but around 20000Km after… here I am again, vibrations are back.

Can’t be warping, can’t be hubs. I suspect on the calipers now but I’m not sure.

I might go to some pads that have less material transfer such as Ferodo DS2500, but other than that, I am very lost.

So wouldn't you recommend the TRW pads? They were on my basket, just doubting at the moment between TRW and Brembo (BMW pads at the moment). DS2500 depending on your use couldn't be the best choice.

[spyro512]

Originally Posted by Dynamites

So wouldn't you recommend the TRW pads? They were on my basket, just doubting at the moment between TRW and Brembo (BMW pads at the moment). DS2500 depending on your use couldn't be the best choice.

for you and for everybody else suffering from this, I might have found at least an answer that makes sense now:

https://www.otto-zimmermann.de/en/service/faq/

See FAQ question Nr. 10.

I'll copypaste it here:

10. Warped brake disc

If vibrations occur under thermal load, the cause is often a "warped brake disc". If the measurement of the brake disc thickness also delivers differing values, the following diagnosis will be regarded as confirmed: Brake disc bent, brake disc "wobbles”, brake disc non-circular, brake disc warped, etc.

But the actual cause of the above stated phenomenon is a different one:

State-of-the-art brake pads are designed for adhesive friction. During a correct run-in braking of the brake disc/pad system a very thin, homogeneous layer of brake pad material is formed through a diffusion processes, on the friction surfaces of the brake disc. Thus there are two friction surfaces (brake disc and pad) which in the marginal zone more or less consist of the same material (particles); a shifting may occur in both directions (diffusion). Thus, the chemical bonds between casting and pad materials can break apart or develop new. This process takes place continuously since there is a smooth transition threshold between the friction surfaces of the brake disc and brake pad.

Failure to observe the brake-in process as well as a non-observance of the run-in phase will cause the formation of uncontrollable and uneven deposits of friction material on the braking surfaces which will result in a partial thermal over stressing of the braking surface. The irregular deposits, which protrude from the surface of the disc will be warmer than the surrounding cast iron. During each contact (once per revolution) of the brake pad with the leading edge of a deposit will increase the temperature at this point. At a temperature between 650° C and 700° C, the cast iron under such a deposit will transition to cementite, and deposits of very hard iron carbide (Fe3C) will form in the crystal lattice of the cast iron. Under very high mechanical and thus thermal loading of the brake, this process is facilitated even more - causing an escalation effect. With an increasing temperature, the cementite will build up and simultaneously penetrate deeper into the brake disc material. Ultimately this process will lead to the above described symptoms, such as rubbing, beating or pulsation of the brake. This can only be remedied through an exchange of the brake discs and brake pads.

It should be noted that the actual cause is not due to a faulty disc. The process described above set into motion through assembly errors, failure to observe the run-in regulations, etc. which damage the originally flawless brake disc.

Additional note:
If you attempt to remove deposits which are not or only barely visible without optical aids through abrasive measures (such as emery cloths, sandpaper, etc.), the condition of the brake disc will worsen even more, since the abrasive particles (mainly alumina) penetrate into the edge layers of the brake disc’s friction surface. For the same reason, these deposits should not removed by sand blasting.





I'll go ahead and change the discs AGAIN, buy proper pads and be extremely careful with the break-in.

[B58Noob]

Did you ever get to the bottom of this. I too am experiencing the same EXACT issue now and am about to replace the front pads and rotors to see if this is causing it . I go to the bmw dealership for service and they did a test ride with me and observed the vibrations but wasn't sure without further diagnostics. He said to replace the front brakes and go from there....

BMW 440i xDrive 2018

[f30.jd__]

Nah fr