[Poochie]

They gave us bigger brakes to match a more potent motor at no added cost; I don't get what all the fuss is about.. I don't care if is needed or not - it's "free" #NoBrainer

[DieGrüneHölle]

Originally Posted by eeyang92

From what I gather, the only point of a BBK is for increased cooling (besides aesthetics) - wouldn't a brake duct produce the same, if not superior, effect? As others have noted, as long as ABS is kicking in, your limitation is your tires, not your brakes?

A brake duct does help with cooling but will not increase the thermal capacity, that is where larger rotors come in.

Repeated hard stops require both effective heat transfer and adequate thermal storage capacity within the disc. The more disc surface area per unit mass and the greater and more efficient the mass flow of air over and through the disc, the faster the heat will be dissipated and the more efficient the entire system will be.

[AlpsRider]

If you don't like the brakes on the M2C because of caliper color or weight, trade them to an M2 owner. While you're at it, update the pads and change the hydraulic fluid. There will be a line of people waiting for that offer You might even make some money on the deal.

[Colinv6]

Is there a part number yet for the M performance brakes in red? Fancy these on my F80!

[DieGrüneHölle]

Originally Posted by Colinv6

Is there a part number yet for the M performance brakes in red? Fancy these on my F80!

Not yet. The word is all Mperf parts will be available in November.

[Colinv6]

Originally Posted by Blipit_

Not yet. The word is all Mperf parts will be available in November.

Thanks buddy.... I didn’t realise it was November for all the parts I’d assumed it was just the roof and the major bits.

Oh well... more time to save up!!

[Franzino]

Originally Posted by Blipit_

Not yet. The word is all Mperf parts will be available in November.

Any guesses how much the M Performance "BMW M Compound Brake Discs of the BMW M Sports Brake System Red" would be for a full front and rear kit?

[JustChris]

Originally Posted by Poochie

After track usage, I'm pretty sure we're going to hear stories like "My Red BBK are now Hello Kitty Hot Pink"

Do you have the real OEM link for these please.

[DieGrüneHölle]

Originally Posted by Franzino

Any guesses how much the M Performance "BMW M Compound Brake Discs of the BMW M Sports Brake System Red" would be for a full front and rear kit?

$3k plus? G30 5 series has a Mperf F/R brake kit, msrp is $3300 usually sells for less than $3k.

[eeyang92]

Originally Posted by Blipit_

A brake duct does help with cooling but will not increase the thermal capacity, that is where larger rotors come in.

Repeated hard stops require both effective heat transfer and adequate thermal storage capacity within the disc. The more disc surface area per unit mass and the greater and more efficient the mass flow of air over and through the disc, the faster the heat will be dissipated and the more efficient the entire system will be.

That makes sense

So this is more of a "side-grade", rather than a straight upgrade. If you find yourself in situations where you need the extra thermal capacity (and are willing to trade a bunch of unsprung weight and rotational mass for it) vs. cooling from ziptie-ing on brake ducts, then it may be worth the tradeoffs.

Although I am a numbers guys... Would be nice to know how much more thermal capacity and cooling we're talking about!

[Poochie]

Originally Posted by JustChris

Do you have the real OEM link for these please.

http://safebraking.com/hello-kitty-brake-package/

Enjoy

[M3 Adjuster]

Originally Posted by Franzino

The main problem is not the brake set-up (calipers / rotors) but the compound of the brake pads... If I have no complaints with the standard blue M2 brakes on the Nurburgring only by fitting different brake pads and uprated brake oil then the same brakes will do fine on hard street driving with only fitting different pads.

TRUE STORY

[M3 Adjuster]

Originally Posted by Poochie

http://safebraking.com/hello-kitty-brake-package/

Enjoy

I saw a Hello Kitty MINI Cooper GP Works this past weekend those would work on..

[Twt]

Originally Posted by eeyang92

That makes sense

So this is more of a "side-grade", rather than a straight upgrade. If you find yourself in situations where you need the extra thermal capacity (and are willing to trade a bunch of unsprung weight and rotational mass for it) vs. cooling from ziptie-ing on brake ducts, then it may be worth the tradeoffs.

Although I am a numbers guys... Would be nice to know how much more thermal capacity and cooling we're talking about!

I switched to the Stoptech 2 piece slotted to my stock M2 which added 60% more air flow/cooling ( along with zip tie ducts) and now have lighter brakes, more cooling at the same cost....too bad BMW didn't think about that rather than using the fat brake parts bin.

[DieGrüneHölle]

You improved air flow with your aero stoptech rotors. But your setup is still inferior to what you call "fat brake parts bin". First off the CCB calipers are some of the best calipers BMW puts on their cars. The 2NH rotors are one-off, as lemetier pointed out having different offsets. The standard brakes with no matter what rotor upgrade, is lacking friction surface area of the 2NH that incorporates larger rotors, larger pads and larger calipers. The increased surface area lends to greater heat capacity and an increased friction surface. Also increasing the diameter of the rotor increases the torque arm and increases the moment of torque for braking. It is like using a breaker bar for more leverage. 2NH owners will also have the opportunity to get lighter aftermarket rotors whether they be iron or carbon ceramic. The new brake kit will work well and I am sure M engineers that tested the car for over a year with the 2NH package will vouch for it.

[Karmic Man]

Originally Posted by RedCarrot

Given the added weight is on the outer diameter of the rotor that is the size of 15-16 inch wheel, I had say the rotational mass multiplier is much closer to the generalized 9X than 2-3X.

It’s a necessary evil for those that truly need it so I am not speaking against it universally. I would just recommend that one should exhaust other brake improvements that do not incur weight penalty before resorting to larger brakes. So often people automatically attribute brake mushiness to overheated rotors, when in fact the causes are overheated brake fluid and brake line expansion. OEM brake pads are typically of low quality (or designed for street-ability) because they don’t meet the eyes and don’t cross the mind of regular car buyers. Upgrading those three things on the base brake kit should provide ample braking performance except for truly hardcore track drivers on demanding tracks.

It’s easy to overlook the base so-called “M” brake kit is already a BBK in itself at 380mm (15”). It’s used on M3/M4 that has an even higher powered S55. I suppose it’s all moot if the larger brake kit is indeed standard on the M2C. I just think it should have been a $1,000 option instead and lower the price increase from $4,500 to $3,500.

And, yes, people should also not get wider tires than what the car needs. It’s a balancing act, like everything in life.

I played around with a 'equivalent static mass' calculator and the shown multiplier with the 11Kg 400mm rotor is not even 2 times.

The only way I can get a multiplier of 2 or above is when the diameter of the rotor is 890mm (35 inches) or above.

http://hpwizard.com/rotational-inertia.html (scroll down to the brake disc section and key in the numbers)

The extra 2Kg in weight on each rotor doesn't amount to much overall weight even when rotational inertia is taken into account.

[M+M]

Originally Posted by beppeM3+123d

The problem is another:
they ask for money for "new" fake brakes that increase weight of 15 kg, a lot for a very similar performance and then they ask for 10000/15000 usd of carbon parts to reduce 15 kg weight.

Anyone can understand that is absolutely crazy.
If you have a budget of 10000 usd you buy ccb and reduce weight of 13,5 where part of this are not suspended parts. You have the best brake ever and you can also make track days.

That's it. all the carbon parts are no sense waste of money and ccb are not available Oem.
Crazy management

Solution is to go aftermarket. AP Racing radi cal saves weight over stock with a 6 piston caliper and rotor for 19 inch wheel and also clears many 18 inch wheels.
https://www.essexparts.com/essex-des...87M2f80M3f82M4

I am running these calipers on my tarmac rally car and they have proven massively better than stock brembos (with race pads) and lighter too even though they are a larger caliper.

[Twt]

Originally Posted by Blipit_

You improved air flow with your aero stoptech rotors. But your setup is still inferior to what you call "fat brake parts bin". First off the CCB calipers are some of the best calipers BMW puts on their cars. The 2NH rotors are one-off, as lemetier pointed out having different offsets. The standard brakes with no matter what rotor upgrade, is lacking friction surface area of the 2NH that incorporates larger rotors, larger pads and larger calipers. The increased surface area lends to greater heat capacity and an increased friction surface. Also increasing the diameter of the rotor increases the torque arm and increases the moment of torque for braking. It is like using a breaker bar for more leverage. 2NH owners will also have the opportunity to get lighter aftermarket rotors whether they be iron or carbon ceramic. The new brake kit will work well and I am sure M engineers that tested the car for over a year with the 2NH package will vouch for it.

While the above may be accurate it avoided the obvious. Virtually every car suitable for tracking has brake cooling ducts....cheapest and most effective way to reduce temps/fade....so where are they? The current brakes are effective for 98% of the M2 users ( with upgraded pads and fluids) so no one was screaming for bigger brakes. This change will prevent us from using the 18 inch/square option, which, together with the original brakes is lighter and provides many more wheel/tire options. I think the marketing department overruled the Motorsport/engineers and just gave priority to the bling factor. Thankfully ,at its core ,the M2 in any configuration is a great street to track car for the masses.By the way F1 brakes are 278mm, so progress in brake design does not always translate to just going bigger.

[RedCarrot]

Originally Posted by CSBM5

The difference in the radius of gyration between the original M2 brakes and the enlarged ones comes nowhere near that level of change. Even if the radius of gyration increased the same amount as the disc (which it doesn't, it's less), it's value increased by 5%. They hysteria surrounding this topic in this forum is beyond anything that makes engineering sense.

Also, people are quoting the increase in "brake weight" and assuming it's all in the disc which is of course false.

No one assumed all the weight is on disc. One poster mentioned 20 lbs which sounds reasonable to me. Of course I don't know for sure so I never even bothered to put a number on rotor weight. You just assumed others assumed...

Originally Posted by Karmic Man

I played around with a 'equivalent static mass' calculator and the shown multiplier with the 11Kg 400mm rotor is not even 2 times.

The only way I can get a multiplier of 2 or above is when the diameter of the rotor is 890mm (35 inches) or above.

http://hpwizard.com/rotational-inertia.html (scroll down to the brake disc section and key in the numbers)

The extra 2Kg in weight on each rotor doesn't amount to much overall weight even when rotational inertia is taken into account.

I am well aware of that site, but guys, you embarked on a whole different metric than the one being discussed. You guys are talking about rotational inertia, and no one is claiming the rotational mass delta would increase the rotor's rotational inertia by a factor of 9. It's madness to even think that. The discussion was what rotational mass means in term of sprung weight on a car. Any car.

The general rule of thumb is fixed unsprung weight (e.g. caliper) has a 4:1 multiplier; while rotational unsprung weight has a 7-10:1 multiplier (many variables at play) in translation to sprung weight. Why else would you think some people shell out BIG bucks on CCB and CF wheels...

[CSBM5]

Those "rules of thumb" shouldn't even be called that as it does a disservice to the term.

Rotational inertia is easily evaluated and can easily be calculated in basic physics models like Cartest2000. I can quickly find out how much impact a change in wheel weight will have on an acceleration segment time for example. The actual changes are almost always far, far smaller than one would be led to believe by stuff you see posted online.

If you want to compare what an added rotor weight will *actually* do on the car, it's a simple process to accurately estimate it. I was referring to people who are making wild claims about static weight comparisons to rotational inertia. Realize that inertial effects are 100% related to acceleration of the rotating mass. For acceleration, they are highest at the slowest speed, and something like accelerating from say 100mph to 120mph the difference in 15% lighter wheels might not even show up on the time segment. Acceleration is highest in 1st gear of course and falls dramatically as speed increases since the power to overcome air drag varies with the cube of velocity.

In any event, the emotions and claims about relatively minor changes are off the charts in some posts compared to the physical reality. However, very few people are interested in the actual physics and actual unbiased data.

[M3 Adjuster]

Originally Posted by norMcal

Pretty sure it will squeal eventually. It always comes and goes, dependigng on the amount of embedded pad material on the rotor. After a track event is is usually pretty quiet for a while.

I suppose your new rotors are quite for now, because they are not worn in yet.
BTW, I switched to PFC08's recently and am not a fan. Not sure why so many love them. I think the Hawk HT-10's have way more bite. I guess it differs depending on driving style.

Also, calipers, which are part of the weight gain of the bigger brakes, aren't part of rotational mass, obviously.

Agree with you here.. they will squeal more and then less depending on how much pad material is embedded on the rotor.

I drove my car to a track event this past weekend.. .... drove my car hard Saturday am in two sessions with DSC off.. and very little squeal.. My GF drove the car two sessions that afternoon with DSC on and they began squealing like a stuck pig (on track even!) and when I drove back to the hotel even the lightest touch of the brakes made a loud squawl. The next day I drove on track with DSC off on Sunday and cleaned them up again and the squeal went away mostly... just in time for the trek home thankfully.

I agree with your comments.


With regards to HAWK vs PF-C brake pads..

Hawk is the KING of initial bite. If you want LOTS of braking force at the moment you hit the pedal.. then Hawk Pads are for you. Many people get addicted to this initial bite.. Once you go Hawk.. you probably won't go away from them.

However... I personally prefer a pad with torque characteristics that give MORE torque the harder you push the pedal.... not just a bunch of torque on the initial press.. For me... when I am braking on track...I want the pads to have good initial torque... and *more* torque when I need more braking force. In other words... if I have made my initial braking effort.. and realize.. OH CRAP.. I need to brake even harder.. I want my brakes to work even harder too.

So.. while some prefer more initial torque.. .. no way man.. I want brake torque equal through the travel.. or.. more brake torque the harder that I push the pedal...... I am an Performance Friction fan all the way and have been for two decades or more. Another good pad with torque characteristics that are steady through the pedal travel is Ferodo.

[Karmic Man]

Originally Posted by RedCarrot

No one assumed all the weight is on disc. One poster mentioned 20 lbs which sounds reasonable to me. Of course I don't know for sure so I never even bothered to put a number on rotor weight. You just assumed others assumed...



I am well aware of that site, but guys, you embarked on a whole different metric than the one being discussed. You guys are talking about rotational inertia, and no one is claiming the rotational mass delta would increase the rotor's rotational inertia by a factor of 9. It's madness to even think that. The discussion was what rotational mass means in term of sprung weight on a car. Any car.

The general rule of thumb is fixed unsprung weight (e.g. caliper) has a 4:1 multiplier; while rotational unsprung weight has a 7-10:1 multiplier (many variables at play) in translation to sprung weight. Why else would you think some people shell out BIG bucks on CCB and CF wheels...

We are talking about equivalent non-rotating mass from the rotational inertia so we are still talking about the same thing!

A increase of 2kg on the rotor does not equate to a increase of 2x9 = 19Kg on the weight of the car as you claimed from a multiplier of 9.

Using their calculator it is an increase of less than 4kg (per rotor) on the overall weight of the car. A multiplier of less than 2!