[///M2CS]

Originally Posted by LukasM2CS

I totally agree with you. CCB reduce weight (looks good), works very good for normal use but you must be very careful on track days. One friend of my have M2CS with CCB and after 3 track days (normal careful driving - same as me with normal brakes) he have to replace 2 sets of brake pads and now eve the disc don't look very good. He will definitely replace the CCB.
It's simple, if they were as good as they say so why wouldn't they have them on M2CS Racing

Exactly !
CCB discs last 3 track days you should know !!!
13 k€

[Bimmed Out]

Originally Posted by LukasM2CS

I totally agree with you. CCB reduce weight (looks good), works very good for normal use but you must be very careful on track days. One friend of my have M2CS with CCB and after 3 track days (normal careful driving - same as me with normal brakes) he have to replace 2 sets of brake pads and now eve the disc don't look very good. He will definitely replace the CCB.
It's simple, if they were as good as they say so why wouldn't they have them on M2CS Racing

Originally Posted by ///M2CS

Exactly !
CCB discs last 3 track days you should know !!!
13 k€

The irony is that any benefit in braking is going to be much more noticeable on the track.

[///M2CS]

[Acetech]

Come on this is total BS, it's hearsay stories like this that get the misinformation going.
As a track veteran and service professional I can tell you I've never seen this happen.
For example I've a friend with a M4 GTS that's 4 years old got over 20 thousand miles and 5 or more track days, his pads are just past 50% worn and his rotors are just fine.
Another customer with a 997 GT3, 10 or more track days per year 4 years no issues, I replaced his pads annually at approximately 50%
Simple rule, occasionally tracking CCBs is fine. If your a track rat doing 20 plus days a year then steel is the smartest choice unless you've got enough $$$ that you don't mind the expense

[///M2CS]

Originally Posted by kepler

The irony is that any benefit in braking is going to be much more noticeable on the track.

this is indeed paradoxical and makes these BMW carbon discs a marketing product some in this forum have been fooled by this proving that dealers are very good at selling unnecessary options

[///M2CS]

Originally Posted by Acetech

Come on this is total BS, it's hearsay stories like this that get the misinformation going.
As a track veteran and service professional I can tell you I've never seen this happen.
For example I've a friend with a M4 GTS that's 4 years old got over 20 thousand miles and 5 or more track days, his pads are just past 50% worn and his rotors are just fine.
Another customer with a 997 GT3, 10 or more track days per year 4 years no issues, I replaced his pads annually at approximately 50%
Simple rule, occasionally tracking CCBs is fine. If your a track rat doing 20 plus days a year then steel is the smartest choice unless you've got enough $$$ that you don't mind the expense

you are very poorly placed to answer you know what a conflict of interest is I guess

[AxM2CS]

Originally Posted by ///M2CS

this is indeed paradoxical and makes these BMW carbon discs a marketing product some in this forum have been fooled by this proving that dealers are very good at selling unnecessary options

To my SA's credit, he discussed it with the knowledgeable staff at the dealership and advised me against CCBs. I had told him the car will be year-round use. They advised I would likely be unhappy with cold/wet performance.

[Acetech]

Originally Posted by ///M2CS

you are very poorly placed to answer you know what a conflict of interest is I guess

I don't understand what you mean?
I have no potential benefit in any outcome

[///M2CS]

Originally Posted by george.ax

To my SA's credit, he discussed it with the knowledgeable staff at the dealership and advised me against CCBs. I had told him the car will be year-round use. They advised I would likely be unhappy with cold/wet performance.

finally a supposed opinion outside the marketing discourse!

[///M2CS]

Originally Posted by Acetech

I don't understand what you mean?
I have no potential benefit in any outcome

I am not a car professional but I do 10 track days a year with a share with all the other participants if carbon discs were the panacea, it would be known

[Acetech]

My post is in response to the suggestion that 3 mild track days would result in 2 pad replacements and potential rotor damage.
Im not debating about tracking superiority.

[///M2CS]

Originally Posted by Acetech

My post is in response to the suggestion that 3 mild track days would result in 2 pad replacements and potential rotor damage.
Im not debating about tracking superiority.

Ok you’re right mild track days are not a problem
But in mild use what’s the interest of CCB brakes vs Steel brakes ?

[GimmeanM]

This has been debated over and over again. Good to see more input but as far as I can tell it comes down to this:

1. Price?
2. Track rat? Better to not select them. Street car? then see question 1.

My car will spend most of it's time in the canyons, so I'm excited to have the lightest M2 possible (going with MT also) and no brake dust on the gold wheels.

[///M2CS]

Originally Posted by GimmeanM

This has been debated over and over again. Good to see more input but as far as I can tell it comes down to this:

1. Price?
2. Track rat? Better to not select them. Street car? then see question 1.

My car will spend most of it's time in the canyons, so I'm excited to have the lightest M2 possible (going with MT also) and no brake dust on the gold wheels.

for your use it is consistent

[RideM]

Everything you need to know about BMW-M CCBs to make an educated purchase:

https://www.bmwux.com/bmw-performanc...mplete-guide/#

[MomoM3]

Originally Posted by VIsldBMW

Everything you need to know about BMW-M CCBs to make an educated purchase:

https://www.bmwux.com/bmw-performanc...mplete-guide/#

That was a good read. Now I want CCBs but it's too late.

[ND40oz]

Originally Posted by MomoM3

That was a good read. Now I want CCBs but it's too late.

Swap the pads and disks and you're there. But it's probably cheaper to buy the full retrofit kit: https://www.getbmwparts.com/oem-part...it-34112358378

[twboy1999]

Can someone confirm

1. It comes with stainless steel brake line for ceramic brake ?

2. Rotor size is 400mm for ceramic

Thanks in advance

[mikeyymonster]

Originally Posted by ND40oz

Swap the pads and disks and you're there. But it's probably cheaper to buy the full retrofit kit: https://www.getbmwparts.com/oem-part...it-34112358378

Damn

[medphysdave]

Originally Posted by ND40oz

Swap the pads and disks and you're there. But it's probably cheaper to buy the full retrofit kit: https://www.getbmwparts.com/oem-part...it-34112358378

That's another reason I got the iron brakes. If I get the itch I can try them out.

[CSBM5]

Notice they don't explain the details on rotational mass in the BMW link. For an engineer, it leaps right out at you when you see all the discussions on line -- a very important variable in rotational mass discussions is the radius of gyration. The radius of gyration is the radius where the rotational mass can be considered located in the basic moment of inertia calculation (i.e. I = m k^2, where m is mass and k is the radius of gyration).

Note that the moment of inertia is a function of the radius of gyration to the 2nd power; hence k has a large effect on rotational inertia as it changes.

In the case here a quick estimate of k for the front brake rotor is about 150mm or 5.9". If you wanted to compare mass located at that k versus say the same mass located at roughly the wheel k, it's k1^2/k2^2. If we consider a 19" wheel to have a radius of gyration located at about 8.5", then popping in these approximate numbers yields 0.48; hence the rotor weight is only 48% as important as the wheel weight in this approximate example.

Put another way, wheel weight contributes 2.1 times more to rotational inertia than disc weight.

This is all back-of-the-envelope quick estimates. However, the effect of radius of gyration is very important in moment of inertia calculations and shouldn't be left out of information any source is providing on "rotating mass" changes.

It's somewhat analogous to the way aero drag coefficients are bandied about by car makers, etc. Comparing two different cars, say one with a Cd of 0.30 and the other a Cd of 0.33 is perhaps "interesting" from an aero design perspective, but without the specified frontal area of the two cars, it tells you absolutely nothing about the aerodynamic drag comparison of the two as the car with the lower Cd could actually have a similar or larger aerodynamic drag...you just don't know without specification of the frontal area.

Sorry...pet peeves of two commonly misunderstood (marketing exploited too) things in the car world.

[MadBimmeRad]

Originally Posted by CSBM5

Notice they don't explain the details on rotational mass in the BMW link. For an engineer, it leaps right out at you when you see all the discussions on line -- a very important variable in rotational mass discussions is the radius of gyration. The radius of gyration is the radius where the rotational mass can be considered located in the basic moment of inertia calculation (i.e. I = m k^2, where m is mass and k is the radius of gyration).

Note that the moment of inertia is a function of the radius of gyration to the 2nd power; hence k has a large effect on rotational inertia as it changes.

In the case here a quick estimate of k for the front brake rotor is about 150mm or 5.9". If you wanted to compare mass located at that k versus say the same mass located at roughly the wheel k, it's k1^2/k2^2. If we consider a 19" wheel to have a radius of gyration located at about 8.5", then popping in these approximate numbers yields 0.48; hence the rotor weight is only 48% as important as the wheel weight in this approximate example.

Put another way, wheel weight contributes 2.1 times more to rotational inertia than disc weight.

This is all back-of-the-envelope quick estimates. However, the effect of radius of gyration is very important in moment of inertia calculations and shouldn't be left out of information any source is providing on "rotating mass" changes.

It's somewhat analogous to the way aero drag coefficients are bandied about by car makers, etc. Comparing two different cars, say one with a Cd of 0.30 and the other a Cd of 0.33 is perhaps "interesting" from an aero design perspective, but without the specified frontal area of the two cars, it tells you absolutely nothing about the aerodynamic drag comparison of the two as the car with the lower Cd could actually have a similar or larger aerodynamic drag...you just don't know without specification of the frontal area.

Sorry...pet peeves of two commonly misunderstood (marketing exploited too) things in the car world.

Thank you for a great breakdown