CCB rotor wear ar 15k (pics)

[MTW1989]

I have just changed the front pads on my CCB'S (pads were at 50%) and today for the first time ive noticed some pitting on the wear indicators?

the car has done 15k miles, and 4 track days last year, but i wouldnt say i drive at 10 10ths on the track.

I have had a look at some posts on ferrari and porsche forums that say this sort of wear on the indicators is nothing to worry about, but can anyone with experience of CCB's give their view?

here are the wear indicators on the front rotors











initially i thought that maybe the dealer had sent the wrong pads? and the pads were for irons not CCB, but i have checked the part numbers on the invoice and they are the correct numbers for CCB pads (plus i cant imagine they would fit if they were not CCB specific pads?)

but they do look different to the oem pads slightly?





so yea, if anyone with CCB experience can shed any light on weather this is a normal wear rate or not, that would be great!

thanks

[Woodengun]

I thought ccb rotors you have to weigh to get wear indication?

The carbon ceramic won't really get appreciably thinner like iron. But if the ccb gets too hot, the carbon oxidizes (ie burns) and this reduces weight of the ccb rotor. It reduces the strength of the rotor and once too much carbon burns the rotor becomes fragile and will physically break during use.

[MTW1989]

Originally Posted by Woodengun

I thought ccb rotors you have to weigh to get wear indication?

The carbon ceramic won't really get appreciably thinner like iron. But if the ccb gets too hot, the carbon oxidizes (ie burns) and this reduces weight of the ccb rotor. It reduces the strength of the rotor and once too much carbon burns the rotor becomes fragile and will physically break during use.

i thought this was the case,

but the small circles pictured on the disc are the "wear indicators" i think when they completely pit they indicate the rotor needs changing

[CanAutM3]

Originally Posted by Woodengun

I thought ccb rotors you have to weigh to get wear indication?

The carbon ceramic won't really get appreciably thinner like iron. But if the ccb gets too hot, the carbon oxidizes (ie burns) and this reduces weight of the ccb rotor. It reduces the strength of the rotor and once too much carbon burns the rotor becomes fragile and will physically break during use.

There are multiple parameters to check to assess CCB wear, if any of them are over the limit, the rotors need to be replaced. Weight is one of them and the wear indicators are another.

See the .pdf in this sticky thread.

[CanAutM3]

Originally Posted by MTW1989

i thought this was the case,

but the small circles pictured on the disc are the "wear indicators" i think when they completely pit they indicate the rotor needs changing

Rotors need to be replaced when the wear indicators are >50% pitted.

[MTW1989]

Originally Posted by CanAutM3

Rotors need to be replaced when the wear indicators are >50% pitted.

hmmm, so going from that, id say mine are probably half way worn out?

[MTW1989]

am i right in thinking that it wouldnt be possible for BMW to send the wrong pads?

is there a set of non CCB pads that would fit these calipers?

just seems weird how they have worn so fast, the indicators have only just deteriorated to this

[CanAutM3]

Originally Posted by MTW1989

am i right in thinking that it wouldnt be possible for BMW to send the wrong pads?

is there a set of non CCB pads that would fit these calipers?

just seems weird how they have worn so fast, the indicators have only just deteriorated to this

What about M5/6 non-CCB pads ? Would those fit?

[IrvineTim]

Curious why you changed the pads if they had 50% left...

[MTW1989]

Originally Posted by thoevelk

Curious why you changed the pads if they had 50% left...

It's well known with CCB's that running pads bellow 50% can cause rotor damage, due to hitting the metal pins in the pad, and something to do with heat dissipation. Things that aren't really an issue with iron discs

[MTW1989]

Originally Posted by CanAutM3

What about M5/6 non-CCB pads ? Would those fit?

Yea that's a point, I think they would, the invoice did have the correct part numbers, I could remove a pad to check, but hey have only been on for about 40 miles? So not sure if they would cause this much accelerated wear in that time?

[MTW1989]

Could be just down to the track days? On a plus side, the Sicom disc refurbishment is around £1600, which isn't bad at all, better than £11,000 I was quoted for replacements at the dealership!

[CanAutM3]

Originally Posted by thoevelk

Curious why you changed the pads if they had 50% left...

CCB rotors wear very fast with higher temperatures due to the oxidation of the fibers inside the matrix, hence why they have a minimum weight limit. Changing pads at 30~50% wear reduces the amount of heat transferred to the rotors during track use and helps prolong rotor life. No need to replace that early on street driven only car.

From the Brake Deep Dive and Interview:

[MTW1989]

If the pads were non CCB pads, would they cause highwr temperature when braking?

[CAOZKAN]

Originally Posted by MTW1989

Could be just down to the track days? On a plus side, the Sicom disc refurbishment is around £1600, which isn't bad at all, better than £11,000 I was quoted for replacements at the dealership!

What is sicom disc refurbishment? I'm using CCB as well the information can come in handy in the future.. 10 track days shouldn't make this wear happen, how long were you on track on these days? My each track day is like 20+20 min driving and I have been to 5-6, my indicators still seems to be untouched..

[Woodengun]

This thread makes bimmerpost worthwhile.

Thank you for the education :-).

[jritt@essex]

I concur that the wear you're seeing is the discs oxidizing, and it is most likely due to the track use. We see this constantly on Corvette (C7 Z06), Camaro, Porsche (991 GT3), Ferrari 458, etc. We've had customers destroy their CCM/CCB discs in as little as 8-10 days on the track. About ten years ago, I was able to destroy a set of CCM discs on my Z06 in a single afternoon at Buttonwillow. Despite what the OEM vehicle manufacturers claim, carbon ceramic discs are currently NOT the best choice for track use. When carbon ceramic discs get too hot, they oxidize. Period, end of story. People argue with us until they're blue in the face, but we see it over and over again.


Below is some info from our website:

In the past few years, Carbon Ceramic brake discs have become increasingly popular on high-end sports cars as either standard equipment or as a factory installed option. Although expensive, they're a great choice for a car that is used exclusively on the street. They save a large amount of unsprung weight, they don't generate much brake dust, have low NVH, and they may even last longer than the rest of the car! For the avid track enthusiast however, they're typically not the best choice.

On the racetrack however, repetitive stops from high speeds generate considerably higher brake disc temperatures vs. what could ever be legally or sanely achieved on the street. Various manufacturers producing the current crop of carbon ceramic discs claim to match iron disc durability on the track, but our experience tells us otherwise. While they may be less resistant to warping or deformation at repeated elevated temperatures, the biggest problem with carbon ceramic discs is that they tend to oxidize at track temperatures, showing rough surface eruptions on the disc face. In some cases the oxidation is terminal (chopped fiber discs), and the discs must be scrapped once it occurs. In other cases (continuous fiber discs), the discs can be resurfaced, but only a limited number of times and at a high cost. Most carbon ceramic discs are measured in terms of minimum mass, rather than the traditional minimum thickness used to measure iron discs. Once the minimum mass is reached, the carbon ceramic disc is trash.

Below is an oxidized carbon ceramic disc from a C7 Z06. The pictured damage was sustained across roughly 8-10 track days. Notice the dark spots in which the surface is flaking off / eroding. When your disc looks like this, it has become a $2,000 paperweight!


Other Potential Pitfalls with Carbon Ceramic Discs

Low airflow- If you look at a specific car model that offers both iron and carbon ceramic discs as an option, the carbon ceramic discs will almost always be considerably larger in overall dimension, with a specific emphasis on a tall radial depth (distance from outer disc edge to inner disc edge). Whereas an iron disc uses a web of directional internal vanes to speed airflow through the disc, most carbon ceramic discs rely on their large surface area to radiate heat into the air surrounding the disc. Hence, the tall radial depth.

Expensive and limited range of compatible brake pads- There aren't many brake pad options with carbon ceramic discs. The pads must be compatible with the specific disc material being used, and if they aren't, they can destroy the discs in a hurry. Since brake pads are a very personal choice to most track junkies, carbon ceramic discs don't provide many options for the driver to chase a desired feel. Also as noted above, carbon ceramic discs tend to be very tall radially, which means very large brake pads are required. In the world of brake pads, price is usually directly proportional to size: Bigger = more expensive.

Poor feel- Experienced drivers will tell you that cast iron discs provide superior pedal feel due to less compress-ability. Some drivers find that carbon ceramic discs feel soft or abrasive at lower temperatures, but feel like stone with little modulation once they heat up. Feel and the resulting confidence is rather important when hurtling towards a guardrail at 150mph!

High replacement disc cost- Carbon ceramic replacement discs can be hideously expensive. If you do wear out or damage a disc, it can cost thousands of dollars to replace each one. When running carbon ceramic discs hard on a racetrack, the odds of having to replace one or more of them increases exponentially vs. if you only drive your car on the street.

Damage-prone- Many manufactures suggest covering their carbon ceramic discs when handling them, so they are not chipped or fractured. One knock when changing a wheel can destroy a disc. Additionally, some chemical wheel cleaners or abrasives used in car detailing can damage carbon ceramic discs.

Splinters- Carbon ceramic discs shouldn't be handled with bare hands, as they can leave carbon splinters in the skin.

Greater sensitivity to burnishing/bedding-in- Most manufacturers have an explicit, and sometimes intricate, set of instructions for bedding-in their carbon ceramic discs. Iron discs can typically be prepared via a simple series of stops from 60-80 mph with the brake pad of choice.

Carbon Ceramic is NOT Carbon/Carbon

At this stage you may be saying to yourself, "But I saw that the XYZ professional race cars were running carbon brakes at the track." The carbon brakes currently being used in professional racing are carbon/carbon (abbreviated C/C), which is actually a different material vs. the carbon ceramic discs used on road cars. The carbon ceramic brake discs on road cars are a Carbon Ceramic Matrix (CCM). In recent times many professional racing series (F1, ALMS, IRL, etc.) have switched to carbon/carbon brake discs in an effort to reduce weight. Carbon/Carbon is an outstanding lightweight material for racing, but requires heat before it starts to generate usable friction. As such, they're completely ill-suited to a typical morning commute in a road car!

When we post the above information, CCM/CCB owners inevitably come out of the woodwork defending the technology. They've invested a large sum of money, so they want to be correct, which is understandable. They tell us we don't know what we're talking about, that BMW, Porsche, or Chevy would never offer CCB's on their halos car if it wasn't the best option for track use, etc. However, the next week we always see another owner post pics of his destroyed discs after he tracks his car repeatedly.

Again, CCM/CCB discs are a wonderful option for road use. When they are operated at high temperatures however, they can and will oxidize. Iron discs are still the best choice for heavy track use. They offer an array of benefits:

Increased airflow- A quality iron racing disc with a high vane count promotes airflow, heat evacuation, and rapid cooling. They don't rely on a large surface area to cool via radiation. The iron discs will move more air than a carbon ceramic disc, and as a result they won't heat your brake pads, caliper pistons, and brake fluid up as quickly. You'll be able to run longer sessions without brake fade, and you'll enjoy the confidence that comes along with them. They'll also make any brake ducts that you have on the car more effective and useful.

Huge range of compatible brake pad compounds- Iron discs will open up a much greater range of available brake pads. You'll be able to achieve a different feel, and tailor your brake setup depending on your needs and environment, whether that is running an AutoX or the most demanding racetrack in your area. You'll also likely be paying less per brake pad set than you were previously, and your pads will last longer.

Inexpensive spare discs- You'll no longer have to spend thousands of dollars when it's time to replace your discs. Iron disc rings typically only cost $300-500 each, so you won't have to stress about anything happening to them. They're inexpensive enough that you can always keep a spare set on hand, so you won't have to worry about any brake-related downtime when you're out at the track.

Durability- Iron discs can take a beating. You can stash your spares in your race trailer, and you won't have to worry about handling them, covering them, dinging them, or chipping them when changing your wheels. Most of all, they don't oxidize. They will eventually crack, but typically last far longer than a carbon ceramic under heavy track use.

I'm using CCB as well the information can come in handy in the future.. 10 track days shouldn't make this wear happen, how long were you on track on these days? My each track day is like 20+20 min driving and I have been to 5-6, my indicators still seems to be untouched

Keep in mind that there are huge number of variables when considering if CCB/CCM discs will work on a given car. What works for one person may not work for another. Some factors that impact the amount of heat being poured into the brake system:
Horsepower
Curb weight
Tire size and compound
Track layout
Driver experience
Length of session
Aero
Brake ducts
etc.

A relatively novice driver at Willow Springs may get 25 track days out of his CCB discs on his unmodified M4 on OEM tires. On the other hand, a gutted M4 with a larger turbo, on slicks, driven by a pro at Road America might only get 6 days before they oxidize. Again, there a huge number of variables, and it's more or less impossible to make a blanket statement about how long a set of CCB's should last.


Our recommendation remains...if you plan to track your car, the best iron racing brake systems will offer superior performance and huge cost savings vs. a CCB system. Our Essex Designed AP Racing Radi-CAL Competition BBK is the perfect example. It even gives you some of the weight savings that the CCB's offer, but spare costs are a fraction of the CCB setup. They're a great investment, because when you pull them off the car and sell them used, you can still recoup 60+% of the purchase price. When you burn up a set of OEM CCB discs, they are pretty much worthless on the used market.

If you do have the CCB system with gold calipers, and you want to track your car consistently, our advice is to shelve the OEM CCB brake system until you sell your car on the used market. Replace them with an iron system designed explicitly for track use. Due to their extremely high replacement cost, the CCB discs will be one of the very first points on the car that any serious buyer considering your car is going to examine. If you don't believe us, look at any 'for sale' ad for a high-end Porsche 911 with CCB's. The first question potential buyers ask is the condition of the discs. If the discs show wear/oxidation, it will have a severe negative impact on your selling price. Nobody wants to buy a used car and then have to immediately shell out $10k for new brake discs.

Carbon ceramic brake technology has evolved quite a bit over the past decade, and continues to march forward. That said, it still can't quite match the performance and cost of a proper iron racing system for track use.

To the OP...if you decide to stick with the CCB's and plan to keep tracking your car, get some good brake ducts to try and bring the operating temps down on the discs. Short of that and the frequent pad changes, there's not a whole lot you can do to slow their oxidation. What you will see next on your discs is that other areas of the disc face will start to look like the wear indicator windows. Eventually the disc will start to look like the pic I posted above.

Hopefully this was helpful, and let us know if we can help you stop throwing money at the CCB's. Thanks.

[Gearhead999s]

Now I am second guessing my plan to use the CCB's on my M4GTS for track duty And yes I am quite hard on brakes on the track!

[Sedan_Clan]

Originally Posted by jritt@essex

I concur that the wear you're seeing is the discs oxidizing, and it is most likely due to the track use. We see this constantly on Corvette (C7 Z06), Camaro, Porsche (991 GT3), Ferrari 458, etc. We've had customers destroy their CCM/CCB discs in as little as 8-10 days on the track. About ten years ago, I was able to destroy a set of CCM discs on my Z06 in a single afternoon at Buttonwillow. Despite what the OEM vehicle manufacturers claim, carbon ceramic discs are currently NOT the best choice for track use. When carbon ceramic discs get too hot, they oxidize. Period, end of story. People argue with us until they're blue in the face, but we see it over and over again.


Below is some info from our website:

In the past few years, Carbon Ceramic brake discs have become increasingly popular on high-end sports cars as either standard equipment or as a factory installed option. Although expensive, they're a great choice for a car that is used exclusively on the street. They save a large amount of unsprung weight, they don't generate much brake dust, have low NVH, and they may even last longer than the rest of the car! For the avid track enthusiast however, they're typically not the best choice.

On the racetrack however, repetitive stops from high speeds generate considerably higher brake disc temperatures vs. what could ever be legally or sanely achieved on the street. Various manufacturers producing the current crop of carbon ceramic discs claim to match iron disc durability on the track, but our experience tells us otherwise. While they may be less resistant to warping or deformation at repeated elevated temperatures, the biggest problem with carbon ceramic discs is that they tend to oxidize at track temperatures, showing rough surface eruptions on the disc face. In some cases the oxidation is terminal (chopped fiber discs), and the discs must be scrapped once it occurs. In other cases (continuous fiber discs), the discs can be resurfaced, but only a limited number of times and at a high cost. Most carbon ceramic discs are measured in terms of minimum mass, rather than the traditional minimum thickness used to measure iron discs. Once the minimum mass is reached, the carbon ceramic disc is trash.

Below is an oxidized carbon ceramic disc from a C7 Z06. The pictured damage was sustained across roughly 8-10 track days. Notice the dark spots in which the surface is flaking off / eroding. When your disc looks like this, it has become a $2,000 paperweight!


Other Potential Pitfalls with Carbon Ceramic Discs

Low airflow- If you look at a specific car model that offers both iron and carbon ceramic discs as an option, the carbon ceramic discs will almost always be considerably larger in overall dimension, with a specific emphasis on a tall radial depth (distance from outer disc edge to inner disc edge). Whereas an iron disc uses a web of directional internal vanes to speed airflow through the disc, most carbon ceramic discs rely on their large surface area to radiate heat into the air surrounding the disc. Hence, the tall radial depth.

Expensive and limited range of compatible brake pads- There aren't many brake pad options with carbon ceramic discs. The pads must be compatible with the specific disc material being used, and if they aren't, they can destroy the discs in a hurry. Since brake pads are a very personal choice to most track junkies, carbon ceramic discs don't provide many options for the driver to chase a desired feel. Also as noted above, carbon ceramic discs tend to be very tall radially, which means very large brake pads are required. In the world of brake pads, price is usually directly proportional to size: Bigger = more expensive.

Poor feel- Experienced drivers will tell you that cast iron discs provide superior pedal feel due to less compress-ability. Some drivers find that carbon ceramic discs feel soft or abrasive at lower temperatures, but feel like stone with little modulation once they heat up. Feel and the resulting confidence is rather important when hurtling towards a guardrail at 150mph!

High replacement disc cost- Carbon ceramic replacement discs can be hideously expensive. If you do wear out or damage a disc, it can cost thousands of dollars to replace each one. When running carbon ceramic discs hard on a racetrack, the odds of having to replace one or more of them increases exponentially vs. if you only drive your car on the street.

Damage-prone- Many manufactures suggest covering their carbon ceramic discs when handling them, so they are not chipped or fractured. One knock when changing a wheel can destroy a disc. Additionally, some chemical wheel cleaners or abrasives used in car detailing can damage carbon ceramic discs.

Splinters- Carbon ceramic discs shouldn't be handled with bare hands, as they can leave carbon splinters in the skin.

Greater sensitivity to burnishing/bedding-in- Most manufacturers have an explicit, and sometimes intricate, set of instructions for bedding-in their carbon ceramic discs. Iron discs can typically be prepared via a simple series of stops from 60-80 mph with the brake pad of choice.

Carbon Ceramic is NOT Carbon/Carbon

At this stage you may be saying to yourself, "But I saw that the XYZ professional race cars were running carbon brakes at the track." The carbon brakes currently being used in professional racing are carbon/carbon (abbreviated C/C), which is actually a different material vs. the carbon ceramic discs used on road cars. The carbon ceramic brake discs on road cars are a Carbon Ceramic Matrix (CCM). In recent times many professional racing series (F1, ALMS, IRL, etc.) have switched to carbon/carbon brake discs in an effort to reduce weight. Carbon/Carbon is an outstanding lightweight material for racing, but requires heat before it starts to generate usable friction. As such, they're completely ill-suited to a typical morning commute in a road car!

When we post the above information, CCM/CCB owners inevitably come out of the woodwork defending the technology. They've invested a large sum of money, so they want to be correct, which is understandable. They tell us we don't know what we're talking about, that BMW, Porsche, or Chevy would never offer CCB's on their halos car if it wasn't the best option for track use, etc. However, the next week we always see another owner post pics of his destroyed discs after he tracks his car repeatedly.

Again, CCM/CCB discs are a wonderful option for road use. When they are operated at high temperatures however, they can and will oxidize. Iron discs are still the best choice for heavy track use. They offer an array of benefits:

Increased airflow- A quality iron racing disc with a high vane count promotes airflow, heat evacuation, and rapid cooling. They don't rely on a large surface area to cool via radiation. The iron discs will move more air than a carbon ceramic disc, and as a result they won't heat your brake pads, caliper pistons, and brake fluid up as quickly. You'll be able to run longer sessions without brake fade, and you'll enjoy the confidence that comes along with them. They'll also make any brake ducts that you have on the car more effective and useful.

Huge range of compatible brake pad compounds- Iron discs will open up a much greater range of available brake pads. You'll be able to achieve a different feel, and tailor your brake setup depending on your needs and environment, whether that is running an AutoX or the most demanding racetrack in your area. You'll also likely be paying less per brake pad set than you were previously, and your pads will last longer.

Inexpensive spare discs- You'll no longer have to spend thousands of dollars when it's time to replace your discs. Iron disc rings typically only cost $300-500 each, so you won't have to stress about anything happening to them. They're inexpensive enough that you can always keep a spare set on hand, so you won't have to worry about any brake-related downtime when you're out at the track.

Durability- Iron discs can take a beating. You can stash your spares in your race trailer, and you won't have to worry about handling them, covering them, dinging them, or chipping them when changing your wheels. Most of all, they don't oxidize. They will eventually crack, but typically last far longer than a carbon ceramic under heavy track use.



Keep in mind that there are huge number of variables when considering if CCB/CCM discs will work on a given car. What works for one person may not work for another. Some factors that impact the amount of heat being poured into the brake system:
Horsepower
Curb weight
Tire size and compound
Track layout
Driver experience
Length of session
Aero
Brake ducts
etc.

A relatively novice driver at Willow Springs may get 25 track days out of his CCB discs on his unmodified M4 on OEM tires. On the other hand, a gutted M4 with a larger turbo, on slicks, driven by a pro at Road America might only get 6 days before they oxidize. Again, there a huge number of variables, and it's more or less impossible to make a blanket statement about how long a set of CCB's should last.


Our recommendation remains...if you plan to track your car, the best iron racing brake systems will offer superior performance and huge cost savings vs. a CCB system. Our Essex Designed AP Racing Radi-CAL Competition BBK is the perfect example. It even gives you some of the weight savings that the CCB's offer, but spare costs are a fraction of the CCB setup. They're a great investment, because when you pull them off the car and sell them used, you can still recoup 60+% of the purchase price. When you burn up a set of OEM CCB discs, they are pretty much worthless on the used market.

If you do have the CCB system with gold calipers, and you want to track your car consistently, our advice is to shelve the OEM CCB brake system until you sell your car on the used market. Replace them with an iron system designed explicitly for track use. Due to their extremely high replacement cost, the CCB discs will be one of the very first points on the car that any serious buyer considering your car is going to examine. If you don't believe us, look at any 'for sale' ad for a high-end Porsche 911 with CCB's. The first question potential buyers ask is the condition of the discs. If the discs show wear/oxidation, it will have a severe negative impact on your selling price. Nobody wants to buy a used car and then have to immediately shell out $10k for new brake discs.

Carbon ceramic brake technology has evolved quite a bit over the past decade, and continues to march forward. That said, it still can't quite match the performance and cost of a proper iron racing system for track use.

To the OP...if you decide to stick with the CCB's and plan to keep tracking your car, get some good brake ducts to try and bring the operating temps down on the discs. Short of that and the frequent pad changes, there's not a whole lot you can do to slow their oxidation. What you will see next on your discs is that other areas of the disc face will start to look like the wear indicator windows. Eventually the disc will start to look like the pic I posted above.

Hopefully this was helpful, and let us know if we can help you stop throwing money at the CCB's. Thanks.

Excellent information!

[MTW1989]

Originally Posted by jritt@essex

I concur that the wear you're seeing is the discs oxidizing, and it is most likely due to the track use. We see this constantly on Corvette (C7 Z06), Camaro, Porsche (991 GT3), Ferrari 458, etc. We've had customers destroy their CCM/CCB discs in as little as 8-10 days on the track. About ten years ago, I was able to destroy a set of CCM discs on my Z06 in a single afternoon at Buttonwillow. Despite what the OEM vehicle manufacturers claim, carbon ceramic discs are currently NOT the best choice for track use. When carbon ceramic discs get too hot, they oxidize. Period, end of story. People argue with us until they're blue in the face, but we see it over and over again.


Below is some info from our website:

In the past few years, Carbon Ceramic brake discs have become increasingly popular on high-end sports cars as either standard equipment or as a factory installed option. Although expensive, they're a great choice for a car that is used exclusively on the street. They save a large amount of unsprung weight, they don't generate much brake dust, have low NVH, and they may even last longer than the rest of the car! For the avid track enthusiast however, they're typically not the best choice.

On the racetrack however, repetitive stops from high speeds generate considerably higher brake disc temperatures vs. what could ever be legally or sanely achieved on the street. Various manufacturers producing the current crop of carbon ceramic discs claim to match iron disc durability on the track, but our experience tells us otherwise. While they may be less resistant to warping or deformation at repeated elevated temperatures, the biggest problem with carbon ceramic discs is that they tend to oxidize at track temperatures, showing rough surface eruptions on the disc face. In some cases the oxidation is terminal (chopped fiber discs), and the discs must be scrapped once it occurs. In other cases (continuous fiber discs), the discs can be resurfaced, but only a limited number of times and at a high cost. Most carbon ceramic discs are measured in terms of minimum mass, rather than the traditional minimum thickness used to measure iron discs. Once the minimum mass is reached, the carbon ceramic disc is trash.

Below is an oxidized carbon ceramic disc from a C7 Z06. The pictured damage was sustained across roughly 8-10 track days. Notice the dark spots in which the surface is flaking off / eroding. When your disc looks like this, it has become a $2,000 paperweight!


Other Potential Pitfalls with Carbon Ceramic Discs

Low airflow- If you look at a specific car model that offers both iron and carbon ceramic discs as an option, the carbon ceramic discs will almost always be considerably larger in overall dimension, with a specific emphasis on a tall radial depth (distance from outer disc edge to inner disc edge). Whereas an iron disc uses a web of directional internal vanes to speed airflow through the disc, most carbon ceramic discs rely on their large surface area to radiate heat into the air surrounding the disc. Hence, the tall radial depth.

Expensive and limited range of compatible brake pads- There aren't many brake pad options with carbon ceramic discs. The pads must be compatible with the specific disc material being used, and if they aren't, they can destroy the discs in a hurry. Since brake pads are a very personal choice to most track junkies, carbon ceramic discs don't provide many options for the driver to chase a desired feel. Also as noted above, carbon ceramic discs tend to be very tall radially, which means very large brake pads are required. In the world of brake pads, price is usually directly proportional to size: Bigger = more expensive.

Poor feel- Experienced drivers will tell you that cast iron discs provide superior pedal feel due to less compress-ability. Some drivers find that carbon ceramic discs feel soft or abrasive at lower temperatures, but feel like stone with little modulation once they heat up. Feel and the resulting confidence is rather important when hurtling towards a guardrail at 150mph!

High replacement disc cost- Carbon ceramic replacement discs can be hideously expensive. If you do wear out or damage a disc, it can cost thousands of dollars to replace each one. When running carbon ceramic discs hard on a racetrack, the odds of having to replace one or more of them increases exponentially vs. if you only drive your car on the street.

Damage-prone- Many manufactures suggest covering their carbon ceramic discs when handling them, so they are not chipped or fractured. One knock when changing a wheel can destroy a disc. Additionally, some chemical wheel cleaners or abrasives used in car detailing can damage carbon ceramic discs.

Splinters- Carbon ceramic discs shouldn't be handled with bare hands, as they can leave carbon splinters in the skin.

Greater sensitivity to burnishing/bedding-in- Most manufacturers have an explicit, and sometimes intricate, set of instructions for bedding-in their carbon ceramic discs. Iron discs can typically be prepared via a simple series of stops from 60-80 mph with the brake pad of choice.

Carbon Ceramic is NOT Carbon/Carbon

At this stage you may be saying to yourself, "But I saw that the XYZ professional race cars were running carbon brakes at the track." The carbon brakes currently being used in professional racing are carbon/carbon (abbreviated C/C), which is actually a different material vs. the carbon ceramic discs used on road cars. The carbon ceramic brake discs on road cars are a Carbon Ceramic Matrix (CCM). In recent times many professional racing series (F1, ALMS, IRL, etc.) have switched to carbon/carbon brake discs in an effort to reduce weight. Carbon/Carbon is an outstanding lightweight material for racing, but requires heat before it starts to generate usable friction. As such, they're completely ill-suited to a typical morning commute in a road car!

When we post the above information, CCM/CCB owners inevitably come out of the woodwork defending the technology. They've invested a large sum of money, so they want to be correct, which is understandable. They tell us we don't know what we're talking about, that BMW, Porsche, or Chevy would never offer CCB's on their halos car if it wasn't the best option for track use, etc. However, the next week we always see another owner post pics of his destroyed discs after he tracks his car repeatedly.

Again, CCM/CCB discs are a wonderful option for road use. When they are operated at high temperatures however, they can and will oxidize. Iron discs are still the best choice for heavy track use. They offer an array of benefits:

Increased airflow- A quality iron racing disc with a high vane count promotes airflow, heat evacuation, and rapid cooling. They don't rely on a large surface area to cool via radiation. The iron discs will move more air than a carbon ceramic disc, and as a result they won't heat your brake pads, caliper pistons, and brake fluid up as quickly. You'll be able to run longer sessions without brake fade, and you'll enjoy the confidence that comes along with them. They'll also make any brake ducts that you have on the car more effective and useful.

Huge range of compatible brake pad compounds- Iron discs will open up a much greater range of available brake pads. You'll be able to achieve a different feel, and tailor your brake setup depending on your needs and environment, whether that is running an AutoX or the most demanding racetrack in your area. You'll also likely be paying less per brake pad set than you were previously, and your pads will last longer.

Inexpensive spare discs- You'll no longer have to spend thousands of dollars when it's time to replace your discs. Iron disc rings typically only cost $300-500 each, so you won't have to stress about anything happening to them. They're inexpensive enough that you can always keep a spare set on hand, so you won't have to worry about any brake-related downtime when you're out at the track.

Durability- Iron discs can take a beating. You can stash your spares in your race trailer, and you won't have to worry about handling them, covering them, dinging them, or chipping them when changing your wheels. Most of all, they don't oxidize. They will eventually crack, but typically last far longer than a carbon ceramic under heavy track use.



Keep in mind that there are huge number of variables when considering if CCB/CCM discs will work on a given car. What works for one person may not work for another. Some factors that impact the amount of heat being poured into the brake system:
Horsepower
Curb weight
Tire size and compound
Track layout
Driver experience
Length of session
Aero
Brake ducts
etc.

A relatively novice driver at Willow Springs may get 25 track days out of his CCB discs on his unmodified M4 on OEM tires. On the other hand, a gutted M4 with a larger turbo, on slicks, driven by a pro at Road America might only get 6 days before they oxidize. Again, there a huge number of variables, and it's more or less impossible to make a blanket statement about how long a set of CCB's should last.


Our recommendation remains...if you plan to track your car, the best iron racing brake systems will offer superior performance and huge cost savings vs. a CCB system. Our Essex Designed AP Racing Radi-CAL Competition BBK is the perfect example. It even gives you some of the weight savings that the CCB's offer, but spare costs are a fraction of the CCB setup. They're a great investment, because when you pull them off the car and sell them used, you can still recoup 60+% of the purchase price. When you burn up a set of OEM CCB discs, they are pretty much worthless on the used market.

If you do have the CCB system with gold calipers, and you want to track your car consistently, our advice is to shelve the OEM CCB brake system until you sell your car on the used market. Replace them with an iron system designed explicitly for track use. Due to their extremely high replacement cost, the CCB discs will be one of the very first points on the car that any serious buyer considering your car is going to examine. If you don't believe us, look at any 'for sale' ad for a high-end Porsche 911 with CCB's. The first question potential buyers ask is the condition of the discs. If the discs show wear/oxidation, it will have a severe negative impact on your selling price. Nobody wants to buy a used car and then have to immediately shell out $10k for new brake discs.

Carbon ceramic brake technology has evolved quite a bit over the past decade, and continues to march forward. That said, it still can't quite match the performance and cost of a proper iron racing system for track use.

To the OP...if you decide to stick with the CCB's and plan to keep tracking your car, get some good brake ducts to try and bring the operating temps down on the discs. Short of that and the frequent pad changes, there's not a whole lot you can do to slow their oxidation. What you will see next on your discs is that other areas of the disc face will start to look like the wear indicator windows. Eventually the disc will start to look like the pic I posted above.

Hopefully this was helpful, and let us know if we can help you stop throwing money at the CCB's. Thanks.

Thanks great info. Tbh I knew going in that fir regular track use they would be a no go, but didn't think they would be half way worn out from just 4 trackdays! Pretty shocked at that! Thought it would only be a problem for regular trackday guys out every weekend!

Ah well, I guess it's either irons that fit the CCB calipers or get the fronts refurbished.

Weird too, no sign of any wear on the backs at all. Even pads have loads of meat left.

Is the rate of the front wear alarming to you guys at all? For 4 track days and 15k? Or can they really go that fast? Although thinking about it, the track I go to, has two big straights that you need to brake hard at 130+ down to 60 for, and another 2 pretty hard braking zones down from 80-90 to 29-30mph, and the track is short, only 3 miles, so I'd imagine as tracks go, that's pretty hard on the brakes

Lesson learnt though! I wont be choosing CCB in future?

Out of interest could you let me know how much your radical brake uptake would be for the M4? I did see them a few weeks back. They look awesome!

[jritt@essex]

Originally Posted by MTW1989

Thanks great info. Tbh I knew going in that fir regular track use they would be a no go, but didn't think they would be half way worn out from just 4 trackdays! Pretty shocked at that! Thought it would only be a problem for regular trackday guys out every weekend!

Yes, the issue of how frequently you track your car is a bit counter-intuitive. I run into the same issue in brake pad discussions all the time. Customers tell me, "Well, I only plan to go to the track twice a year, so I don't need a crazy race pad, right?" Stop and think about that for a second. Your car doesn't know how many times it's going to the track. All it 'knows' is the conditions that it will encounter at the track on any given day. That means if you take your brakes to 1500F repeatedly during a single session, the components need to be able to handle that temperature. The frequency of abuse does make a difference on how long it will take to completely decimate a component, since the abuse is aggregate. That said, I've seen all sorts of bad things happen to OEM road car brakes in a single track session though...incinerated dust boots, pad fade, fluid fade, caliper paint turning colors, cracked discs...you name it. Every component has a failure threshold. In many cases all it takes is one trip past the maximum operating temperature of any given brake component to do damage. When you start stacking up the trips past that threshold, it all just turns to scrap more quickly.

As I mentioned in my last post, in most cases there are just too many variables to definitively predict if you and your car, on your track, with your mods are going to destroy the brakes in one session or fourteen sessions. As such, you need to be a good boy scout and "be prepared." That means your brake components must be up to snuff for any trip to the searing brake temps the track produces...one time, or a hundred times...it doesn't matter. If they aren't, you're gambling with their destruction.

Ah well, I guess it's either irons that fit the CCB calipers or get the fronts refurbished.

A big problem with going with iron discs that directly replace the OEM CCB's is weight. As mentioned in my previous post, CCB discs are purposefully made to have more surface area to radiate heat. That's why they are always larger than their iron counterparts on the same chassis. They have a very tall radial depth. When you convert that very large disc into iron, it makes the disc extremely heavy. A 410mm iron disc with the radial depth of the OEM CCB's is going to be about 30 lbs.! For reference, the 372x34mm discs in our Radi-CAL Pro5000R kits weighs about 21 lbs. When you replace a CCB disc with iron of the same size, you're adding a massive amount of unsprung weight, which pretty much is the primary purpose of the CCB's in the first place! Also, you're moving that mass further out away from the hub, which makes it even harder to accelerate and decelerate...further killing performance.

Swapping out your CCB's for their iron equivalent would basically be like installing 22" chrome wheels.

Weird too, no sign of any wear on the backs at all. Even pads have loads of meat left.

That's not too surprising at all actually. We see the exact same thing on other front engine, RWD cars like the Corvette. Front brake usage is much, much greater than the rear. We have C7 Z06 guys who switch to our complete front brake package and leave their OEM CCB rear system on the car. Since our kit replicates front torque output closely, there's no reason not to do so. It looks a little funky, but from a functional standpoint it works well.

Keep in mind that later this year we'll be releasing a matching rear Pro5000R complete BBK.

On something like a Porsche 911, the rear engine/RWD drivetrain layout dictates that the car will use relatively more brake compared to something like an M3 or Corvette. The weight shift going into a brake zone is much different with all that weight behind the rear axle. The wear/abuse on the front and rear are more balanced on the Porsche, whereas on the M3/M4, the fronts take the brunt of the beating.

Out of interest could you let me know how much your radical brake uptake would be for the M4? I did see them a few weeks back. They look awesome!

Thanks! They are insane. You can see all the details/price on our site. We have two options. The CP9660/372mm takes a more standard 18mm thick pad and fits behind OEM M4 wheels without a spacer. The CP9668/372mm uses a 25mm thick pad and requires a spacer.

[CAOZKAN]

Originally Posted by MTW1989

It's well known with CCB's that running pads bellow 50% can cause rotor damage, due to hitting the metal pins in the pad, and something to do with heat dissipation. Things that aren't really an issue with iron discs

How did you understand that they're 50% used, I hear very weird noises from front when I brake and even though my rotors seems okay, I want to make sure the pads are still good. My rear pads have cornered shape and fronts are flat, I wonder if they were supposed to be cornered as well? If not, do you happen to know what is the original thickness of the front pads?