CCB or aftermarket Brembo brakes?

[CanAutM3]

Originally Posted by swamp2

I have no idea what you mean here. A mass factor is a well defined thing and in its denominator of its terms (other than the 1) are a total vehicle mass and wheel radius not a component mass nor component radius. This mass is obviously orders of magnitude different between the two. If you want to use your own formula you should show how you derive it and what it physically means. Sure you can write the formula, it has consistent units, but I just can't see any meaning to it.

The mass factor of this CF driveshaft basically adds about 20% of its mass to the solely translating mass. I don't see how you can get a result like this with your formula.

Mass factor is pretty straight forward:

mf=(m+Ʃme)/m

Where Ʃme is the sommation of the equivalent mass of the rotating components

You can either calculate the mass factor of the entire vehicle by using m=mass of the vehicle, or you can calculate the mass factors of individual components by using m=mass of the component. Both methods work because me for the individual components remains independent of the reference mass.

As I posted previously, equivalent mass is dependent on the ratio between translational and rotational acceleration. So for the driveshaft you need the final drive ratio and the rolling radius. I think I see where there could be confusion: the r in mass factor furmula is the rolling radius while the r in the inertia formula is the shaft radius.

And again, since I/m is needed in the component mass factor formula and I is directly proportional to m, you don't need the component mass to establish its mass factor (the geometric characteristics that define I are sufficient). Vehicle mass is also not needed. From your driveshaft assumptions:

I = m/2*r^2 + 2*(m/4)*r^2/2
I/m = r^2/2 + 2*(1/4)*r^2/2
I/m = 3/4r^2

With rdriveshaft=0.06m, Nf=3.462 and rrolling=0.33755m

mfdriveshaft = 1 + 3/4*rdriveshaft^2 * Nf^2/rrolling^2 = 1.284

So if we assume this driveshaft weighs 8kg as you did, it adds 2.27kg (0.284*8kg) of equivalent mass to the car.

Now, do the math for the driveshaft's impact on the mass factor of the whole car and you get mf=1.0015147 for a 1500kg car. Effective mass = m * mf = 1502.27kg. So the 8kg driveshaft adds 2.27kg of equivalent mass. Exact same result

Originally Posted by swamp2

Agree, but it appears you are right for the wrong reason.

Nope, for the right reasons

[swamp2]

Originally Posted by CanAutM3

Mass factor is pretty straight forward:
...
Nope, for the right reasons

Other than your initial typo I worked out the math. Conceptually and for the actual drive shaft we are in agreement. This is somewhat just a name disagreement. A mass factor is always dimensionless and corrects a vehicle weight due to inertia by multiplying by the full base mass. An equivalent mass is how much weight is added to the base weight. You have used the terms somewhat interchangeably. I do stand corrected that vehicle mass and tire radius are not required to calculate equivalent mass, it is needed to calculate mass factor.

There is also the detail as to the weighting of terms according to no weight, Nf^2 or (Nt*Nf)^2. Thus your prior formula can not be used for both wheels and brakes and driveshaft.

[l!ve]

Originally Posted by Sedan_Clan

I love hearing from Porsche guys who have CCB's. The perspective is well worth reading.

I bought a 997TT with steel brakes then upgraded them to Porsche's CCBs. I also have a Ferrari with CCBs. Both cars are 100% road cars as I prefer dedicated track cars. CCBs are great. Benefits on the street are there, but if you look at them strictly from a cost to braking power angle, you're probably better going with bigger steel brakes from Brembo. However, CCB does give you weight savings and no brake dust. Does that matter to you? You decide. To me, nothing is needed on a street car - CF, lighter wheels, exhaust, intake, etc. all overkill on the street. But that doesn't mean we don't get it. M3, Porsche, Ferrari are all luxury items we get to enjoy. Their values are special to us as individual owners. Spend the $8k where it'll make your heart smile most. Or save it for something else. For me, I went CCB.

[CanAutM3]

Originally Posted by swamp2

Other than your initial typo I worked out the math. Conceptually and for the actual drive shaft we are in agreement. This is somewhat just a name disagreement. A mass factor is always dimensionless and corrects a vehicle weight due to inertia by multiplying by the full base mass. An equivalent mass is how much weight is added to the base weight. You have used the terms somewhat interchangeably.

Where does it say that mass factor is limited to the entire vehicle?

As for definitions, according to Gillespie:

Equivalent mass is the mass added to factor the rotation of the components
Effective mass is the sum of equivalent mass and base mass
Mass factor is the ratio between effective mass and base mass

As I noted prior, the terms are used differently depending on which publication I read. I already admited that I loosely interchanged the terms equivalent and effective mass and I should have been consistent. But I never interchanged mass factor and equivalent mass.

Originally Posted by swamp2

tire radius are not required to calculate equivalent mass

Tire or rolling radius is needed to calculate both the component mass factor and its equivalent mass.

Originally Posted by swamp2

There is also the detail as to the weighting of terms according to no weight, Nf^2 or (Nt*Nf)^2. Thus your prior formula can not be used for both wheels and brakes and driveshaft.

Agreed, and I did post this point here. The ratio in the formula needs to be adapted depending on which component is evaluated.

Crankshaft, flywheel, transmission input shaft
(Nt*Nf)^2/rrolling^2

Drive shaft, transmission output shaft:
Nf^2/rrolling^2

Diff, half shafts, brake discs/drums, wheels, tires:
1/rrolling^2

And it is the latter factor I used when estimating the effective mass savings of the CCB (to bring us back on topic ).

[Musashi]

First, would like to thank the post members for having it, this post is invaluable at gaining insight on the CCB. I have no doubt that this type of community will drive the eventual mass production of CCB's. I am not an engineer, nor a racer, but am relying on basic scientific or technical knowledge to retrieve published authoritative expertise arguments and bring them here.

Summary: There is no performance difference between CCB's and high-grade , high-quality cast iron discs, and am demonstrating, as concisely as possible, why it is so, and keep math or physics to a minimum. But that aside, I would buy CCB's the first opportunity, and most certainly on the next gen M3, which I believe will probably be all carbon fiber and even more exceptional.

FORMULA 1

In the 1990s F1s evolution was reducing the braking boundaries at distances so short that overtaking was headed towards obsoletion. FIA rules altered braking regulations to increase the braking distance, which included limiting the input assist, reducing rotor diameter etc. Dimension wise:

11.3.2 All discs must have a maximum thickness of 28mm and a maximum outside diameter of 278mm (Source: F1)

Weight: 4 discs = 1.5kg or 13.2 lbs total. That is over 30lbs shaved off regular CCB's. In addition, wheel size limits the CCB disc, and that will change as larger wheels have already been tested in F1. However, a reminder that F1 and FIA do not want better braking or it will prevent overtaking.

Within the F1 dimensions, the only material that can deliver is CCB. Athough CCB's have a poor performance below 400°C and optimum braking performance above 650°C.” (Source Racecar Engineering). Typical T= 1200 Deg C. The short acceleration and deceleration timings, F1 rotor temperature spikes over 1000 Deg C. As ABS is banned in F1, the thermal requirement prohibit cast iron as it cannot survive the temperatures. Ceramic is the only material that can do the job.

In a full season, Brembo supplies each team with the following material for two cars (http://www.brembo.com/en/Press/Comun...hip%202014.pdf)

• 10 sets of calipers (i.e. 4 x 10 components)
• Between 140 and 240 discs (or 35 to 60 sets)
• Between 280 and 480 pads

For 20 events, averaging 350 kms race and a generous 200kms for testing and quals, total is 11,000 kms x 2 cars = 22,000kms / 35 to 60 sets or a median replacement frequency of 370kms (one race) to 630 kms per set!!! CCB's get replaced before half-life and even before 20% life is used or after one hard braking incident. F1 teams learned that anything over 200kms, CCB's may develop critical cracks that can fracture the CCB. A single braking action can also do it. Post race X-Rays and in-race failures demonstrated this amply, such as the article below.:

Tech explanation, Brembo F1 CCB failure, Tech info, Ferrari’s own CCB's: http://www.racecar-engineering.com/t...brake-systems/

As if not sufficient, 2015 F1 CCB's are changing again to improve reliability. So even CCB evolution demonstrates that CCB's are not created equal.

F80, M3 M3 GT2 PORSCHE PORSCHE GT CORVETTE ETC

Back to M3 and GT. F1s max weight is 691kgs vs 1290 / M3 GT2. As the mathematical posts above demonstrated (I decided against adding Force, Mass, acceleration, etc equations), unsprung mass matters a lot for fast cars. F1s accelerate 0-100 in 1.7 seconds, nearly 1-2 seconds faster that most GT cars. Half the weight, x 3-4 G force, higher tire footprint ratio, lower body, any F1 can slow down, for the same speed, nearly THREE times faster than the average GT.

Combined with faster acceleration, the cooling cycle for F1 CCB's is nearly HALF (1/2) the GT cooling period. And more frequent. Or disc Area is

A=πr2 CCB at 278mm = 2427 sq cm, and for 400mm= 5026 sq cm. Twice the size for commercial CCB's. Note, F1 discs are THINNER as well. So about 2.5 three times more cooling surface/volume in commercial CCB's than F1.

Energy kinetic = Ek = ½mv2. M for mass. Means that at equal speed, GT must dissipate TWICE as much energy (twice or more the mass)

Common question, “Ok, so twice the car mass, thrice the rotor, means same braking right? That Porsche or M3 will brake like the F1?”

No. Car acceleration, and traction force will relate to brute HP (400-800 hp), weight, mass, tires, temperature, unpsrung weight etc. Calculator: http://www.engineeringtoolbox.com/ca...on-d_1309.html For an M3 and Porsche 911 GT, Mass is x 2-3 higher, Traction lower, CoG higher, 1/2 vs 3/4 G Force, accelerate slower, and have more than twice the mass and Ek at the same time and space and speed. However, other variables intervene (height, CoG, traction, etc), and consequently, the braking is not just x2, but nearly 3 times slower to get the car into a safe max speed apex. Add to it ABS and longer deceleration time, these GT car cast iron discs have more than sufficient time for thermal dissipation and to cool down, since the cooling rate is similar to CCB but with more ample time to spare..

Example: at Spa-Francorchamps, at the Kemmel Straight, approaching turn 7 at Les Combres, an M3 GT2 can accelerate up to 320, then must hit the brakes the latest at the 200m marker and arrive at 100-110km/hr, whereas the F1 can do so drop from 345km/hr commencing braking at the 100-75 m marc, and could enter the turn at 120-140km/hr. In practice, everyone is a bit slower, as tire degradation and track temperature will affect this from lap to lap. http://upload.wikimedia.org/wikipedi...of_Belgium.svg

The technical data from the article attached, “Optimizing carbon- ceramic brake disc design for same-size replacement of cast iron discs” is one of many that demonstrate that there is NO difference whatsoever between CCB and cast iron performance with the larger commercial dimensions. Some fading is indeed noted, but both retain their effectiveness within the same envelope. The F1 environment is different, as the technical limitations do not allow for cast iron.

Additional articles inside academic libraries discuss the topic, but these cannot be reproduced without author permissions. Bottom-line, M3, M3 GT2, Porsche 911 GT usage, the cooling cycle is longer and more than sufficient to allow for identical performance between cast iron and CCB. Furthermore, cast iron being four times cheaper, the esteemed Porsche racers are very wise to substitute their CCB's. However, experienced racers are also experienced brakers; poor braking techniques on cast iron can push their limits, increase fading, but that does not prove, empirically, that CCB's are superior. As a base offering in some cases, such as the F80, the BMW M Performance brakes are terrific (BMW M Performance videos repeat in fast succession dozens of 250-0 km/hr braking cycles that prove their resilience). Coupled with additional pad and braking liquid modifications, all race grade sports cast iron discs are equal in performance to CCB's, and actually superior when operating below 400C,..

ANOTHER CCB PROBLEM: FRACTURE RISK

As illustrated by the F1 reality and extensive CCB testing, track degradation of CCB's is nearly identical. But CCB life-cycle is actually much shorter. A few laps on a CCB can create micro fractures that can fail catastrophically one or both front discs, and jeopardize the driver. Unless taking the CCB's and xRay-ing them after each track day, a CCB user topping 300-100 km/hr even once per lap is increasing exponentially his risk by keeping them on. In F1 they do not bother and simply discard them or give them to Brembo before they head for clock makers and become beautiful sports ornaments. For a DD, he can microfracture the CCB, and keep driving on it for months or years without knowing; but he may be one hard deceleration away from CCB fracture.

The deduction is that one cannot buy CCB’s, track them ten times for 100 laps per year, and expect a similar lifelong performance as cast irons tracked as well 100 laps per year. The risk of catastrophic failure of CCB's increases exponentially with each major deceleration. By 9th month of occasional tracking, at Indianapolis (Laguna Seca being a slower circuit), cumulative lap 80, the front CCBs are likely done and can just fracture, whereas, at their worst, high-grade cast irons will retain form and provide advanced failure feedback, such as pulsations etc while retaining integrity. This again speaks in favor of those installing cast irons for races. The fracture risk is one of those hidden risks CCB manufacturers carefully omit from the sale's pitch. But that is why they do not warrant them if tracked.

Unsprung weight: As per previous posts math, for an F1, dropping 30lbs is a significant weight reduction that can be used in KERS etc. Math in previous posts is correct, the ability to get that F1 0-100km/hr in 1.7 seconds directly relates to horse power, mass, traction. But in a car three times heavier, it does not matter as much.

Why buy CCB's? There are some outstanding reasons.

• Cost: In 250,000 kms driving two Japanese cars, I replaced 4 sets of rotors. At least two were lost to warpage, or premature corrosion related degradation impacting thermal properties, and they failed during two single braking incidents... Zing coasting lasts 10,000 hrs in salt, or about a winter. Cadmium plating lasts lifetime of rotor but is hard to come by. GT grade cast irons gave me longer lifespan (80,000-140,000 kms), but the bottom line? I spent $4,000 in brakes on a low end car. Yet, a single CCB set would have lasted me this distance and still be about half life…
• Unlimited $, you can track and replace them at will, money never an issue;
• CCB's look terrific (no one can dispute that);
• Branding;
• Somewhat better braking performance but only if comparing them with rusting cast irons in 3d year (M Perfromance/ German iron lasts much longer than other brands even if exposed to salt); BMW’s argument is a bit misleading. Any other time and space, or track, it is identical;
• Will drive the car DD in nice weather, spirited digressive driving, and minimal track performance;
• Zero rust: true, but most high-end sports cars are not driven them in winter. That aside, Porsches can be easily seen in Canadian winters, some with CCBs,, owners assured by the knowledge that salt will never attack the aluminum frame nor discs. That in turn, promotes better looks. As carbon and alloy frames multiply, so will be winter driving. Anti-corrosion properties cannot be ignored;
• Lifetime brakes. A rapid 250,000 kms wear on a high-end sporty car, driven 15,000 kms/year that is 16 years, quite the deal! Porsche and BMW CCB's can probably last over 350,000 kms spirited and DD and even with occasional tracking. One would have to be really unlucky to get a crack.
• 8k is not that much more for you vs overall cost of car;
• You always have access to a qualified wheel installer that WILL NEVER crack your disk mounting tires etc.
• All of the above considered, 8k is a bargain, be it a higher up-front cost.

Why not to get them

• Race track performance- no difference;
• Intend on selling car in 3-5 years, which case next owner may not accept them;
• Intend to track the car frequently and do not want to bother with spare cast iron sets;
• You hate squeal sound when the CCB's are cold, especially in winter. The -18C to -30C (-4F to -22F) we had recently (Ottawa, Montreal, twice as cold in Winnipeg), there was nowhere I could even warm up my M Performance set. 30 min drive, out of car, they are not even lukewarm... Hard braking is out of the question, too slippery even on dry asphalt with winter tires. CCB's would squeal incessantly in these conditions, meaning, Summertime car only;
• May genuinely be financially on the edge in which case an M3 is itself a doubtful commitment;
• Little to no access to specialized center that can safely remove your rims each time.

As I wrote at the beginning, I would get them in an instant, even for my F30 if they were produced. That aside, I do believe that the cost potential for CCB's should not exceed that of cast iron (2-4k per set), but only if they were mass produced.

Thank you!!

Sources

http://www.engineeringtoolbox.com/ca...on-d_1309.html
Brembo. http://www.brembo.com/en/Press/Comun...hip%202014.pdf
http://www.surface-transforms.com/fi...march_2014.pdf (Attached)
F1 Regulations, http://www.formula1.com/inside_f1/ru.../8696/fia.html
“F1 2014 explained: Brake systems”, Racecar Engineering, last edited Jul 2014, http://www.racecar-engineering.com/t...brake-systems/

Attachments

“Optimising carbon- ceramic brake disc design for same-size replacement of cast iron discs.” SMMT Innovation and Technology, Spring 2014, http://www.surface-transforms.com/fi...march_2014.pdf
and Brembo's communique..

[AM4ZING]

I ordered my 6MT M4 with M CCB. By bmw offering carbon ceramic brakes on the M4, it's almost like a test to see how bad us M drivers want more.. By more
I mean more POWER & TORQUE on the future M models

[M4TW]

Originally Posted by Musashi

First, would like to thank the post members for having it, this post is invaluable at gaining insight on the CCB. I have no doubt that this type of community will drive the eventual mass production of CCB's. I am not an engineer, nor a racer, but am relying on basic scientific or technical knowledge to retrieve published authoritative expertise arguments and bring them here.

Summary: There is no performance difference between CCB's and high-grade , high-quality cast iron discs, and am demonstrating, as concisely as possible, why it is so, and keep math or physics to a minimum. But that aside, I would buy CCB's the first opportunity, and most certainly on the next gen M3, which I believe will probably be all carbon fiber and even more exceptional.

FORMULA 1

In the 1990s F1s evolution was reducing the braking boundaries at distances so short that overtaking was headed towards obsoletion. FIA rules altered braking regulations to increase the braking distance, which included limiting the input assist, reducing rotor diameter etc. Dimension wise:

11.3.2 All discs must have a maximum thickness of 28mm and a maximum outside diameter of 278mm (Source: F1)

Weight: 4 discs = 1.5kg or 13.2 lbs total. That is over 30lbs shaved off regular CCB's. In addition, wheel size limits the CCB disc, and that will change as larger wheels have already been tested in F1. However, a reminder that F1 and FIA do not want better braking or it will prevent overtaking.

Within the F1 dimensions, the only material that can deliver is CCB. Athough CCB's have a poor performance below 400°C and optimum braking performance above 650°C.” (Source Racecar Engineering). Typical T= 1200 Deg C. The short acceleration and deceleration timings, F1 rotor temperature spikes over 1000 Deg C. As ABS is banned in F1, the thermal requirement prohibit cast iron as it cannot survive the temperatures. Ceramic is the only material that can do the job.

In a full season, Brembo supplies each team with the following material for two cars (http://www.brembo.com/en/Press/Comun...hip%202014.pdf)

• 10 sets of calipers (i.e. 4 x 10 components)
• Between 140 and 240 discs (or 35 to 60 sets)
• Between 280 and 480 pads

For 20 events, averaging 350 kms race and a generous 200kms for testing and quals, total is 11,000 kms x 2 cars = 22,000kms / 35 to 60 sets or a median replacement frequency of 370kms (one race) to 630 kms per set!!! CCB's get replaced before half-life and even before 20% life is used or after one hard braking incident. F1 teams learned that anything over 200kms, CCB's may develop critical cracks that can fracture the CCB. A single braking action can also do it. Post race X-Rays and in-race failures demonstrated this amply, such as the article below.:

Tech explanation, Brembo F1 CCB failure, Tech info, Ferrari’s own CCB's: http://www.racecar-engineering.com/t...brake-systems/

As if not sufficient, 2015 F1 CCB's are changing again to improve reliability. So even CCB evolution demonstrates that CCB's are not created equal.

F80, M3 M3 GT2 PORSCHE PORSCHE GT CORVETTE ETC

Back to M3 and GT. F1s max weight is 691kgs vs 1290 / M3 GT2. As the mathematical posts above demonstrated (I decided against adding Force, Mass, acceleration, etc equations), unsprung mass matters a lot for fast cars. F1s accelerate 0-100 in 1.7 seconds, nearly 1-2 seconds faster that most GT cars. Half the weight, x 3-4 G force, higher tire footprint ratio, lower body, any F1 can slow down, for the same speed, nearly THREE times faster than the average GT.

Combined with faster acceleration, the cooling cycle for F1 CCB's is nearly HALF (1/2) the GT cooling period. And more frequent. Or disc Area is

A=πr2 CCB at 278mm = 2427 sq cm, and for 400mm= 5026 sq cm. Twice the size for commercial CCB's. Note, F1 discs are THINNER as well. So about 2.5 three times more cooling surface/volume in commercial CCB's than F1.

Energy kinetic = Ek = ½mv2. M for mass. Means that at equal speed, GT must dissipate TWICE as much energy (twice or more the mass)

Common question, “Ok, so twice the car mass, thrice the rotor, means same braking right? That Porsche or M3 will brake like the F1?”

No. Car acceleration, and traction force will relate to brute HP (400-800 hp), weight, mass, tires, temperature, unpsrung weight etc. Calculator: http://www.engineeringtoolbox.com/ca...on-d_1309.html For an M3 and Porsche 911 GT, Mass is x 2-3 higher, Traction lower, CoG higher, 1/2 vs 3/4 G Force, accelerate slower, and have more than twice the mass and Ek at the same time and space and speed. However, other variables intervene (height, CoG, traction, etc), and consequently, the braking is not just x2, but nearly 3 times slower to get the car into a safe max speed apex. Add to it ABS and longer deceleration time, these GT car cast iron discs have more than sufficient time for thermal dissipation and to cool down, since the cooling rate is similar to CCB but with more ample time to spare..

Example: at Spa-Francorchamps, at the Kemmel Straight, approaching turn 7 at Les Combres, an M3 GT2 can accelerate up to 320, then must hit the brakes the latest at the 200m marker and arrive at 100-110km/hr, whereas the F1 can do so drop from 345km/hr commencing braking at the 100-75 m marc, and could enter the turn at 120-140km/hr. In practice, everyone is a bit slower, as tire degradation and track temperature will affect this from lap to lap. http://upload.wikimedia.org/wikipedi...of_Belgium.svg

The technical data from the article attached, “Optimizing carbon- ceramic brake disc design for same-size replacement of cast iron discs” is one of many that demonstrate that there is NO difference whatsoever between CCB and cast iron performance with the larger commercial dimensions. Some fading is indeed noted, but both retain their effectiveness within the same envelope. The F1 environment is different, as the technical limitations do not allow for cast iron.

Additional articles inside academic libraries discuss the topic, but these cannot be reproduced without author permissions. Bottom-line, M3, M3 GT2, Porsche 911 GT usage, the cooling cycle is longer and more than sufficient to allow for identical performance between cast iron and CCB. Furthermore, cast iron being four times cheaper, the esteemed Porsche racers are very wise to substitute their CCB's. However, experienced racers are also experienced brakers; poor braking techniques on cast iron can push their limits, increase fading, but that does not prove, empirically, that CCB's are superior. As a base offering in some cases, such as the F80, the BMW M Performance brakes are terrific (BMW M Performance videos repeat in fast succession dozens of 250-0 km/hr braking cycles that prove their resilience). Coupled with additional pad and braking liquid modifications, all race grade sports cast iron discs are equal in performance to CCB's, and actually superior when operating below 400C,..

ANOTHER CCB PROBLEM: FRACTURE RISK

As illustrated by the F1 reality and extensive CCB testing, track degradation of CCB's is nearly identical. But CCB life-cycle is actually much shorter. A few laps on a CCB can create micro fractures that can fail catastrophically one or both front discs, and jeopardize the driver. Unless taking the CCB's and xRay-ing them after each track day, a CCB user topping 300-100 km/hr even once per lap is increasing exponentially his risk by keeping them on. In F1 they do not bother and simply discard them or give them to Brembo before they head for clock makers and become beautiful sports ornaments. For a DD, he can microfracture the CCB, and keep driving on it for months or years without knowing; but he may be one hard deceleration away from CCB fracture.

The deduction is that one cannot buy CCB’s, track them ten times for 100 laps per year, and expect a similar lifelong performance as cast irons tracked as well 100 laps per year. The risk of catastrophic failure of CCB's increases exponentially with each major deceleration. By 9th month of occasional tracking, at Indianapolis (Laguna Seca being a slower circuit), cumulative lap 80, the front CCBs are likely done and can just fracture, whereas, at their worst, high-grade cast irons will retain form and provide advanced failure feedback, such as pulsations etc while retaining integrity. This again speaks in favor of those installing cast irons for races. The fracture risk is one of those hidden risks CCB manufacturers carefully omit from the sale's pitch. But that is why they do not warrant them if tracked.

Unsprung weight: As per previous posts math, for an F1, dropping 30lbs is a significant weight reduction that can be used in KERS etc. Math in previous posts is correct, the ability to get that F1 0-100km/hr in 1.7 seconds directly relates to horse power, mass, traction. But in a car three times heavier, it does not matter as much.

Why buy CCB's? There are some outstanding reasons.

• Cost: In 250,000 kms driving two Japanese cars, I replaced 4 sets of rotors. At least two were lost to warpage, or premature corrosion related degradation impacting thermal properties, and they failed during two single braking incidents... Zing coasting lasts 10,000 hrs in salt, or about a winter. Cadmium plating lasts lifetime of rotor but is hard to come by. GT grade cast irons gave me longer lifespan (80,000-140,000 kms), but the bottom line? I spent $4,000 in brakes on a low end car. Yet, a single CCB set would have lasted me this distance and still be about half life…
• Unlimited $, you can track and replace them at will, money never an issue;
• CCB's look terrific (no one can dispute that);
• Branding;
• Somewhat better braking performance but only if comparing them with rusting cast irons in 3d year, BMW’s argument is a bit misleading. Any other time and space, or track, it is identical;
• Will drive the car DD in nice weather, spirited digressive driving, and minimal track performance;
• Zero rust: true, but most high-end luxury cars do not drive them in winter. That aside, seen quite a few Porsches driven in Canadian winters, CCB's, owners assured by the knowledge that salt will never attack the frame. That in turn, promotes better looks. As carbon and alloy frames multiply, so will be winter driving. Anti-corrosion properties cannot be ignored;
• Lifetime brakes. A rapid 250,000 kms wear on a high-end sporty car, driven 15,000 kms/year that is 16 years, quite the deal! Porsche and BMW CCB's can probably last over 350,000 kms spirited and DD and even with occasional tracking. One would have to be really unlucky to get a crack.
• 8k is not that much more for you vs overall cost of car;
• You always have access to a qualified wheel installer that WILL NEVER crack your disk mounting tires etc.
• All of the above considered, 8k is a bargain, be it a higher up-front cost.

Why not to get them

• Race track performance- no difference;
• Intend on selling car in 3-5 years, which case next owner may not accept them;
• Intend to track the car frequently and do not want to bother with spare cast iron sets;
• You hate squeal sound when the CCB's are cold, especially in winter. The -18C to -30C (-4F to -22F) we had recently (Ottawa, Montreal, twice as cold in Winnipeg), there was nowhere I could even warm up my M Performance set. 30 min drive, out of car, they are not even lukewarm... Hard braking is out of the question, too slippery even on dry asphalt with winter tires. CCB's would squeal incessantly in these conditions, meaning, Summertime car only;
• May genuinely be financially on the edge in which case an M3 is itself a doubtful commitment;
• Little to no access to specialized center that can safely remove your rims each time.

As I wrote at the beginning, I would get them in an instant, even for my F30 if they were produced. That aside, I do believe that the cost potential for CCB's should not exceed that of cast iron (2-4k per set), but only if they were mass produced.

Thank you!!

Sources

http://www.engineeringtoolbox.com/ca...on-d_1309.html
Brembo. http://www.brembo.com/en/Press/Comun...hip%202014.pdf
http://www.surface-transforms.com/fi...march_2014.pdf (Attached)
F1 Regulations, http://www.formula1.com/inside_f1/ru.../8696/fia.html
“F1 2014 explained: Brake systems”, Racecar Engineering, last edited Jul 2014, http://www.racecar-engineering.com/t...brake-systems/

Attachments

“Optimising carbon- ceramic brake disc design for same-size replacement of cast iron discs.” SMMT Innovation and Technology, Spring 2014, http://www.surface-transforms.com/fi...march_2014.pdf
and Brembo's communique..

Outstanding and informative post!!! Thank you for pulling that information together. I'm not qualified to challenge anything you have assembled, but can speak of my own experiences. It gets cold here in Sask. too , but I haven't noticed any problems with squealing or reduced performance. The only time I've had trouble is coming out of a touchless car wash on a frigid day.

[Musashi]

Originally Posted by AM4ZING

I ordered my 6MT M4 with M CCB. By bmw offering carbon ceramic brakes on the M4, it's almost like a test to see how bad us M drivers want more.. By more
I mean more POWER & TORQUE on the future M models

They look terrific, and with spirited DD they should last over 350,000/400,000 kms. Being familiar with Carbon fiber construction (road cycling), mass production of CCBs and carbon based products can be far cheaper than current high end metal and steel. It can be molded. Printed (in the future). No specialized treatments, coatings, bathing, rustproofing and just painting needed. No specialized assembly (heat and pressure glued so no robots soldering). It is just a question of time, volume and all this is the future of M cars is post i9- carbon body, CCBs, and all lines, 3 series, M, supercar. The can even alter the CCB compound to reduce operating temperature but still preserve corrosion resistance and similar weight.

Right now I wish it was offered in 370/390 M Performance sizes as well. For Canada, corrosion resistance and predictable performance are extremely appealing.

[Musashi]

Originally Posted by M4TW

Outstanding and informative post!!! Thank you for pulling that information together. I'm not qualified to challenge anything you have assembled, but can speak of my own experiences. It gets cold here in Sask. too , but I haven't noticed any problems with squealing or reduced performance. The only time I've had trouble is coming out of a touch-less car wash on a frigid day.

You are welcome. It was lingering on my mind for weeks before I got the time to essay it.

Well broken in rotors with matching pads should rarely squeal, but high grade components do that at times and it compliments the quality of material. Lived in Manitoba and Saskatchewan, it gets very cold as well. What I miss about those provinces is the compacted-snowy roads which were fun to drive. Too cold for salts and more compact ice. What gets me irked in the QC/Ontario is the 'generous' amount of salts and fluorides splattered everywhere, my car is white at times. Roads stay wet until -15...!!! Have to wash it once/two times a week. And rustproofed the sub-chassis (a top garage does it no holes, under warranty) and saves the sub-chassis items from 24/7 /summertime moisture and salts trapped behind the aerodynamic film.

Question, how do you find your CCBs? Initial bite driving in cold weather? And your car's reaction? At -15C and below I find my F30 so cold and sluggish at everything from gear shifts, acceleration, tires, suspension, I baby it 10-20 mins until it warms up or it just does not respond.

[CanAutM3]

Originally Posted by Musashi

First, would like to thank the post members for having it, this post is invaluable at gaining insight on the CCB. I have no doubt that this type of community will drive the eventual mass production of CCB's. I am not an engineer, nor a racer, but am relying on basic scientific or technical knowledge to retrieve published authoritative expertise arguments and bring them here.

Summary: There is no performance difference between CCB's and high-grade , high-quality cast iron discs, and am demonstrating, as concisely as possible, why it is so, and keep math or physics to a minimum. But that aside, I would buy CCB's the first opportunity, and most certainly on the next gen M3, which I believe will probably be all carbon fiber and even more exceptional.

FORMULA 1

In the 1990s F1s evolution was reducing the braking boundaries at distances so short that overtaking was headed towards obsoletion. FIA rules altered braking regulations to increase the braking distance, which included limiting the input assist, reducing rotor diameter etc. Dimension wise:

11.3.2 All discs must have a maximum thickness of 28mm and a maximum outside diameter of 278mm (Source: F1)

Weight: 4 discs = 1.5kg or 13.2 lbs total. That is over 30lbs shaved off regular CCB's. In addition, wheel size limits the CCB disc, and that will change as larger wheels have already been tested in F1. However, a reminder that F1 and FIA do not want better braking or it will prevent overtaking.

Within the F1 dimensions, the only material that can deliver is CCB. Athough CCB's have a poor performance below 400°C and optimum braking performance above 650°C.” (Source Racecar Engineering). Typical T= 1200 Deg C. The short acceleration and deceleration timings, F1 rotor temperature spikes over 1000 Deg C. As ABS is banned in F1, the thermal requirement prohibit cast iron as it cannot survive the temperatures. Ceramic is the only material that can do the job.

In a full season, Brembo supplies each team with the following material for two cars (http://www.brembo.com/en/Press/Comun...hip%202014.pdf)

• 10 sets of calipers (i.e. 4 x 10 components)
• Between 140 and 240 discs (or 35 to 60 sets)
• Between 280 and 480 pads

For 20 events, averaging 350 kms race and a generous 200kms for testing and quals, total is 11,000 kms x 2 cars = 22,000kms / 35 to 60 sets or a median replacement frequency of 370kms (one race) to 630 kms per set!!! CCB's get replaced before half-life and even before 20% life is used or after one hard braking incident. F1 teams learned that anything over 200kms, CCB's may develop critical cracks that can fracture the CCB. A single braking action can also do it. Post race X-Rays and in-race failures demonstrated this amply, such as the article below.:

Tech explanation, Brembo F1 CCB failure, Tech info, Ferrari’s own CCB's: http://www.racecar-engineering.com/t...brake-systems/

As if not sufficient, 2015 F1 CCB's are changing again to improve reliability. So even CCB evolution demonstrates that CCB's are not created equal.

F80, M3 M3 GT2 PORSCHE PORSCHE GT CORVETTE ETC

Back to M3 and GT. F1s max weight is 691kgs vs 1290 / M3 GT2. As the mathematical posts above demonstrated (I decided against adding Force, Mass, acceleration, etc equations), unsprung mass matters a lot for fast cars. F1s accelerate 0-100 in 1.7 seconds, nearly 1-2 seconds faster that most GT cars. Half the weight, x 3-4 G force, higher tire footprint ratio, lower body, any F1 can slow down, for the same speed, nearly THREE times faster than the average GT.

Combined with faster acceleration, the cooling cycle for F1 CCB's is nearly HALF (1/2) the GT cooling period. And more frequent. Or disc Area is

A=πr2 CCB at 278mm = 2427 sq cm, and for 400mm= 5026 sq cm. Twice the size for commercial CCB's. Note, F1 discs are THINNER as well. So about 2.5 three times more cooling surface/volume in commercial CCB's than F1.

Energy kinetic = Ek = ½mv2. M for mass. Means that at equal speed, GT must dissipate TWICE as much energy (twice or more the mass)

Common question, “Ok, so twice the car mass, thrice the rotor, means same braking right? That Porsche or M3 will brake like the F1?”

No. Car acceleration, and traction force will relate to brute HP (400-800 hp), weight, mass, tires, temperature, unpsrung weight etc. Calculator: http://www.engineeringtoolbox.com/ca...on-d_1309.html For an M3 and Porsche 911 GT, Mass is x 2-3 higher, Traction lower, CoG higher, 1/2 vs 3/4 G Force, accelerate slower, and have more than twice the mass and Ek at the same time and space and speed. However, other variables intervene (height, CoG, traction, etc), and consequently, the braking is not just x2, but nearly 3 times slower to get the car into a safe max speed apex. Add to it ABS and longer deceleration time, these GT car cast iron discs have more than sufficient time for thermal dissipation and to cool down, since the cooling rate is similar to CCB but with more ample time to spare..

Example: at Spa-Francorchamps, at the Kemmel Straight, approaching turn 7 at Les Combres, an M3 GT2 can accelerate up to 320, then must hit the brakes the latest at the 200m marker and arrive at 100-110km/hr, whereas the F1 can do so drop from 345km/hr commencing braking at the 100-75 m marc, and could enter the turn at 120-140km/hr. In practice, everyone is a bit slower, as tire degradation and track temperature will affect this from lap to lap. http://upload.wikimedia.org/wikipedi...of_Belgium.svg

The technical data from the article attached, “Optimizing carbon- ceramic brake disc design for same-size replacement of cast iron discs” is one of many that demonstrate that there is NO difference whatsoever between CCB and cast iron performance with the larger commercial dimensions. Some fading is indeed noted, but both retain their effectiveness within the same envelope. The F1 environment is different, as the technical limitations do not allow for cast iron.

Additional articles inside academic libraries discuss the topic, but these cannot be reproduced without author permissions. Bottom-line, M3, M3 GT2, Porsche 911 GT usage, the cooling cycle is longer and more than sufficient to allow for identical performance between cast iron and CCB. Furthermore, cast iron being four times cheaper, the esteemed Porsche racers are very wise to substitute their CCB's. However, experienced racers are also experienced brakers; poor braking techniques on cast iron can push their limits, increase fading, but that does not prove, empirically, that CCB's are superior. As a base offering in some cases, such as the F80, the BMW M Performance brakes are terrific (BMW M Performance videos repeat in fast succession dozens of 250-0 km/hr braking cycles that prove their resilience). Coupled with additional pad and braking liquid modifications, all race grade sports cast iron discs are equal in performance to CCB's, and actually superior when operating below 400C,..

ANOTHER CCB PROBLEM: FRACTURE RISK

As illustrated by the F1 reality and extensive CCB testing, track degradation of CCB's is nearly identical. But CCB life-cycle is actually much shorter. A few laps on a CCB can create micro fractures that can fail catastrophically one or both front discs, and jeopardize the driver. Unless taking the CCB's and xRay-ing them after each track day, a CCB user topping 300-100 km/hr even once per lap is increasing exponentially his risk by keeping them on. In F1 they do not bother and simply discard them or give them to Brembo before they head for clock makers and become beautiful sports ornaments. For a DD, he can microfracture the CCB, and keep driving on it for months or years without knowing; but he may be one hard deceleration away from CCB fracture.

The deduction is that one cannot buy CCB’s, track them ten times for 100 laps per year, and expect a similar lifelong performance as cast irons tracked as well 100 laps per year. The risk of catastrophic failure of CCB's increases exponentially with each major deceleration. By 9th month of occasional tracking, at Indianapolis (Laguna Seca being a slower circuit), cumulative lap 80, the front CCBs are likely done and can just fracture, whereas, at their worst, high-grade cast irons will retain form and provide advanced failure feedback, such as pulsations etc while retaining integrity. This again speaks in favor of those installing cast irons for races. The fracture risk is one of those hidden risks CCB manufacturers carefully omit from the sale's pitch. But that is why they do not warrant them if tracked.

Unsprung weight: As per previous posts math, for an F1, dropping 30lbs is a significant weight reduction that can be used in KERS etc. Math in previous posts is correct, the ability to get that F1 0-100km/hr in 1.7 seconds directly relates to horse power, mass, traction. But in a car three times heavier, it does not matter as much.

Why buy CCB's? There are some outstanding reasons.

• Cost: In 250,000 kms driving two Japanese cars, I replaced 4 sets of rotors. At least two were lost to warpage, or premature corrosion related degradation impacting thermal properties, and they failed during two single braking incidents... Zing coasting lasts 10,000 hrs in salt, or about a winter. Cadmium plating lasts lifetime of rotor but is hard to come by. GT grade cast irons gave me longer lifespan (80,000-140,000 kms), but the bottom line? I spent $4,000 in brakes on a low end car. Yet, a single CCB set would have lasted me this distance and still be about half life…
• Unlimited $, you can track and replace them at will, money never an issue;
• CCB's look terrific (no one can dispute that);
• Branding;
• Somewhat better braking performance but only if comparing them with rusting cast irons in 3d year (M Perfromance/ German iron lasts much longer than other brands even if exposed to salt); BMW’s argument is a bit misleading. Any other time and space, or track, it is identical;
• Will drive the car DD in nice weather, spirited digressive driving, and minimal track performance;
• Zero rust: true, but most high-end sports cars are not driven them in winter. That aside, Porsches can be easily seen in Canadian winters, some with CCBs,, owners assured by the knowledge that salt will never attack the aluminum frame nor discs. That in turn, promotes better looks. As carbon and alloy frames multiply, so will be winter driving. Anti-corrosion properties cannot be ignored;
• Lifetime brakes. A rapid 250,000 kms wear on a high-end sporty car, driven 15,000 kms/year that is 16 years, quite the deal! Porsche and BMW CCB's can probably last over 350,000 kms spirited and DD and even with occasional tracking. One would have to be really unlucky to get a crack.
• 8k is not that much more for you vs overall cost of car;
• You always have access to a qualified wheel installer that WILL NEVER crack your disk mounting tires etc.
• All of the above considered, 8k is a bargain, be it a higher up-front cost.

Why not to get them

• Race track performance- no difference;
• Intend on selling car in 3-5 years, which case next owner may not accept them;
• Intend to track the car frequently and do not want to bother with spare cast iron sets;
• You hate squeal sound when the CCB's are cold, especially in winter. The -18C to -30C (-4F to -22F) we had recently (Ottawa, Montreal, twice as cold in Winnipeg), there was nowhere I could even warm up my M Performance set. 30 min drive, out of car, they are not even lukewarm... Hard braking is out of the question, too slippery even on dry asphalt with winter tires. CCB's would squeal incessantly in these conditions, meaning, Summertime car only;
• May genuinely be financially on the edge in which case an M3 is itself a doubtful commitment;
• Little to no access to specialized center that can safely remove your rims each time.

As I wrote at the beginning, I would get them in an instant, even for my F30 if they were produced. That aside, I do believe that the cost potential for CCB's should not exceed that of cast iron (2-4k per set), but only if they were mass produced.

Thank you!!

Sources

http://www.engineeringtoolbox.com/ca...on-d_1309.html
Brembo. http://www.brembo.com/en/Press/Comun...hip%202014.pdf
http://www.surface-transforms.com/fi...march_2014.pdf (Attached)
F1 Regulations, http://www.formula1.com/inside_f1/ru.../8696/fia.html
“F1 2014 explained: Brake systems”, Racecar Engineering, last edited Jul 2014, http://www.racecar-engineering.com/t...brake-systems/

Attachments

“Optimising carbon- ceramic brake disc design for same-size replacement of cast iron discs.” SMMT Innovation and Technology, Spring 2014, http://www.surface-transforms.com/fi...march_2014.pdf
and Brembo's communique..

This essay has so many flaws, I don't quite know where to start...

Two points to start:

First, F1 (Carbon/Carbon) do not use the same material as CCB (Carbon Ceramic Brakes), so any comparison is pretty meaningless.

Second, one of the reason F1s can brake in such short distances, is the huge downforce they generate combined with very sticky rubber. The challenge of the braking system is to be able to dissipate the heat fast enough to fully exploit the available grip.

[Musashi]

Originally Posted by CanAutM3

This essay has so many flaws, I don't quite know where to start...

Two points to start:

First, F1 (Carbon/Carbon) do not use the same material as CCB (Carbon Ceramic Brakes), so any comparison is pretty meaningless.

Second, one of the reason F1s can brake in such short distances, is the huge downforce they generate combined with very sticky rubber. The challenge of the braking system is to be able to dissipate the heat fast enough to fully exploit the available grip.

On flaws, please do start. However, ensure argument validity as that is the easiest one to debunk analytically. First, you may need to re-read the entire threat then. The F1 comparison is not meaningless and, argumentatively, was inserted precisely as other forum members mentioned F1 as a comparison. Secondly, you missed the entire C range of conclusions, including that there is no comparison between F1 braking and the CCB. In addition, my initial reply covered the spectrum of considerations including modifications some members considered for track, and some users modify the initial CCB of their F80. The core of the analysts were the disks themselves, and whether Carbon Industries or Brembo, the desks are baked and cooked in a similar fashion, with different dimensions for F1.

One of the important entires I made earlier is that indeed many factors affect the F1 braking other than the brakes and I quote "Car acceleration, and traction force will relate to brute HP (400-800 hp), weight, mass, tires, temperature, unpsrung weight etc. " Most of sources used were expertise references, which indicates my post was not carefully read.

The F1 downforce argument is not cogent in itself, nor using a comparison, as most performance GT cars that lack the downforce have instead the 2 to3x weight factor stabilizing the car. F1's need it as the ratio of power to weight and speed is such they can take off. And the Veyron is so fast at 444km/hr that is needs a light speed aeronautical control sensor to generate 30% of its braking with rear wing excessive air braking by changing the Cd, something not allowed in F1.

More on F1 braking can be found here: http://www.f1technical.net/articles/2

Downforce is not a factor in F1 braking but stability and cornering. If what you said is correct, then F1s could never be fast as the downforce would constantly slow them down or kill their tires. At 100km/hr the downforce is exponentially smaller than at 300km/hr, quite a small factor, yet F1s brake incredibly fast in less than 2 seconds. On a straight line, 1 second behind an opponent in pre-determined sectors, F1s are allowed to reduce downforce to accelerate and pass by opening the rear winglet. Many times even that is not sufficient while the front car still has its rear wing closed. So the F1 world is a constant compromise between downforce for stability, handling, traction, cornering, and it is not even close to being the most important braking factor- tire temperature being a far bigger one.

What does the F1 world say? "The aerodynamic designer has two primary concerns: the creation of downforce, to help push the car's tyres onto the track and improve cornering forces; and minimising the drag that gets caused by turbulence and acts to slow the car down...In a bid to cut speeds, the FIA robbed the cars of a chunk of downforce by raising the front wing, bringing the rear wing forward and modifying the rear diffuser profile. Most of those innovations were effectively outlawed under even more stringent aero regulations imposed by the FIA for 2009. The changes were designed to promote overtaking by making it easier for a car to closely follow another. http://www.formula1.com/inside_f1/un...cing/5281.html

QED. F1 downforce is used to stabilize and make it safely faster, not brake it. F1 reducing and regulating downforce over the years has not reduced the vehicle's braking abilities.

The point of the thread was determining if CCBs are worth it and it has been demonstrated, amply, that CCBs offer no braking or track advantage vs cast irons; they have clear aesthetic advantages but some clear disadvantages if intended for high speed tracking and braking, mainly, very short life expectancy.

[CanAutM3]

Originally Posted by Musashi

On flaws, please do start. However, ensure argument validity as that is the easiest one to debunk analytically. First, you may need to re-read the entire threat then. The F1 comparison is not meaningless and, argumentatively, was inserted precisely as other forum members mentioned F1 as a comparison. Secondly, you missed the entire C range of conclusions, including that there is no comparison between F1 braking and the CCB. In addition, my initial reply covered the spectrum of considerations including modifications some members considered for track, and some users modify the initial CCB of their F80. The core of the analysts were the disks themselves, and whether Carbon Industries or Brembo, the desks are baked and cooked in a similar fashion, with different dimensions for F1.

One of the important entires I made earlier is that indeed many factors affect the F1 braking other than the brakes and I quote "Car acceleration, and traction force will relate to brute HP (400-800 hp), weight, mass, tires, temperature, unpsrung weight etc. " Most of sources used were expertise references, which indicates my post was not carefully read.

The F1 downforce argument is not cogent in itself, nor using a comparison, as most performance GT cars that lack the downforce have instead the 2 to3x weight factor stabilizing the car. F1's need it as the ratio of power to weight and speed is such they can take off. And the Veyron is so fast at 444km/hr that is needs a light speed aeronautical control sensor to generate 30% of its braking with rear wing excessive air braking by changing the Cd, something not allowed in F1.

More on F1 braking can be found here: http://www.f1technical.net/articles/2

Downforce is not a factor in F1 braking but stability and cornering. If what you said is correct, then F1s could never be fast as the downforce would constantly slow them down or kill their tires. At 100km/hr the downforce is exponentially smaller than at 300km/hr, quite a small factor, yet F1s brake incredibly fast in less than 2 seconds. On a straight line, 1 second behind an opponent in pre-determined sectors, F1s are allowed to reduce downforce to accelerate and pass by opening the rear winglet. Many times even that is not sufficient while the front car still has its rear wing closed. So the F1 world is a constant compromise between downforce for stability, handling, traction, cornering, and it is not even close to being the most important braking factor- tire temperature being a far bigger one.

What does the F1 world say? "The aerodynamic designer has two primary concerns: the creation of downforce, to help push the car's tyres onto the track and improve cornering forces; and minimising the drag that gets caused by turbulence and acts to slow the car down...In a bid to cut speeds, the FIA robbed the cars of a chunk of downforce by raising the front wing, bringing the rear wing forward and modifying the rear diffuser profile. Most of those innovations were effectively outlawed under even more stringent aero regulations imposed by the FIA for 2009. The changes were designed to promote overtaking by making it easier for a car to closely follow another. http://www.formula1.com/inside_f1/un...cing/5281.html

QED. F1 downforce is used to stabilize and make it safely faster, not brake it. F1 reducing and regulating downforce over the years has not reduced the vehicle's braking abilities.

The point of the thread was determining if CCBs are worth it and it has been demonstrated, amply, that CCBs offer no braking or track advantage vs cast irons; they have clear aesthetic advantages but some clear disadvantages if intended for high speed tracking and braking, mainly, very short life expectancy.

What do you mean downforce has no incidence on braking ?

Do you understand basic physics?

Because downforce increases the normal force on the tires it increase tire grip in every direction, not only cornering. The tires can generate much more grip while braking because of the downforce. One of the big challenge for F1 drivers is modulating the brake force as the car slows down. Since there is less and less downforce as the car decelerates, the driver needs to progressively release the pressure on the brakes.

Because there is so much braking force available due to the downforce, the challenge of the system is to be able to dissipate a huge amount of energy in a very short time. A very powerful (power=energy/time) braking system is needed to exploit the available grip.

As another tidbit, the drag generated by F1 downforce devices is so strong, that simply lifting off the throttle at top speed can generate over 1g of decelaration.

[simpelton]

First post, can't create a new thread. Anyway, read lots about CCB vs steel. What I would like to know is y'all experience with wear on the steels. How many miles/km's before replacing pads and rotors if anyone has got that far, please include if you track the car, DD, or run canyons etc every weekend and push hard. I want to figure out how often I would replace the pads and rotors on steels to make a call on steel vs CCB. Thanking you

[James_m4]

Slightly different tack. Is it possible to put the M5/M6 front 6 pot caliper on the OEM M3/4 front rotor?

Any if so and maybe if the front to back biased is too large could you then not put the OEM M3/4 4 pot calliper on the rear and not change rotor sizes?

[FTS]

Originally Posted by simpelton

First post, can't create a new thread. Anyway, read lots about CCB vs steel. What I would like to know is y'all experience with wear on the steels. How many miles/km's before replacing pads and rotors if anyone has got that far, please include if you track the car, DD, or run canyons etc every weekend and push hard. I want to figure out how often I would replace the pads and rotors on steels to make a call on steel vs CCB. Thanking you

Cast iron rotors should last several years with normal driving, canyon runs, etc. On the track you should at least get 1,000 track miles out of them, I am estimating based on general past experience with iron rotors of similar size.

Originally Posted by Suzuka

Slightly different tack. Is it possible to put the M5/M6 front 6 pot caliper on the OEM M3/4 front rotor?

Any if so and maybe if the front to back biased is too large could you then not put the OEM M3/4 4 pot calliper on the rear and not change rotor sizes?

No you cannot mix and match cast iron rotor sizes to the CCB calipers, diameters are too far apart. Also, if you install the proper size rotors with the CCB calipers, or similar sized other calipers, you will likely need to replace the brake booster as well and possibly the master cylinder. The volume of the CCB calipers are significantly higher than stock calipers. The part numbers for the brake booster between blue and gold brakes are different, but it appears that the master cylinders are the same.

[simpelton]

Thanks FTS, what about the normal OEM Street pads? How much ware if the car is driven hard on a regular basis?

[FTS]

Originally Posted by simpelton

Thanks FTS, what about the normal OEM Street pads? How much ware if the car is driven hard on a regular basis?

I cannot even guess that one, I don't know which compound they are using frankly, sorry.

[Tempe Mendoan]

Originally Posted by syl2121201

I was considering the bmw CCB, since I really want big 6/4 piston brake on the new m4, and I will maybe do several track days per year. Is it worth the 8000+ bucks, or just get some after market brakes with the steel rotor? Any advice for the quantity and pricing for these brakes?

Get the CCB and you won't regret it. It's awesome.

[johnnyfast11]

Originally Posted by l!ve

I bought a 997TT with steel brakes then upgraded them to Porsche's CCBs. I also have a Ferrari with CCBs. Both cars are 100% road cars as I prefer dedicated track cars. CCBs are great. Benefits on the street are there, but if you look at them strictly from a cost to braking power angle, you're probably better going with bigger steel brakes from Brembo. However, CCB does give you weight savings and no brake dust. Does that matter to you? You decide. To me, nothing is needed on a street car - CF, lighter wheels, exhaust, intake, etc. all overkill on the street. But that doesn't mean we don't get it. M3, Porsche, Ferrari are all luxury items we get to enjoy. Their values are special to us as individual owners. Spend the $8k where it'll make your heart smile most. Or save it for something else. For me, I went CCB.

you speak my language. you and i both could be friends.