Just for the record my name is Gary Cogis and I work for Race Technologies, the High Performance representative for Brembo, and distributor of the aftermarket BBK's for North America.
I was forwarded this thread from a few of our authorized dealers who are sponsors of this board and felt it was important to be able to address many of the issues mentioned in this thread. I thought it may be useful to explain the selection process, and purpose, for the components used in the Brembo BBK's along with Brembo's criteria for brake design to better understand what you accomplish and gain with the Brembo upgrade.
The brake system engineered specifically for the new M3 uses a 380x34mm 2pc. fully floating disc with a 6-piston Monobloc caliper for the front, and a 380x28mm 2pc. fully floating disc with a 4-piston Monobloc caliper for the rear. You can thank BMW personally for the need to utilize a 380x34mm disc in the front brake system.
One of the main purposes of a performance oriented BBK is to increase heat capacity of the system for repeatable braking performance with maximum fade resistance. The benefit of using a 2pc disc with an aluminum hat is to also reduce unsprung and rotational weight at the same time as increasing the overall diameter of the disc. The overall diameter, thickness, and annulus (swept area) of the OEM disc is such that the available 355mm discs would not have been a significant enough increase (and in some cases a decrease) of heat capacity, therefore not being an appropriate choice for the purpose of improving performance. We are well aware of the desire to run 18" wheels and tires for high performance track use and examined many disc options before selecting this disc.
As with any Brembo brake kit, the design criteria is based on achieving a beneficial improvement in performance and longevity while not compromising safety or driveability. Aesthetics is not one of the initial design criterias, but a byproduct of following the design cues from our professional racing products and adding a variety of colors. If we could have provided a 355mm (14") option while achieving the desired performance improvement and better wheel fitment we absolutely would have.
While we are on the topic of wheel fitment, there are a number of popular 18" wheels that do clear the Brembo BBK. Many popular wheel manufacturers are also coming to us directly to be proactive and ensure that future wheels designs will reflect the popularity of larger BBKs. Currently there are wheels from HRE, Volk Racing, CCW and a few others that work perfectly without spacers. As the horsepower of high performance production vehicles increases and the cars do not get any lighter, disc diameters will need to increase to provide the necessary heat sink to handle the job of converting gross amounts of kinetic energy into heat. A good, but unfortunate example of this is the new Nissan Skyline GTR. Has anyone taken a look at the size of the OEM brakes on that car?
The second issue I wanted to address is the use of a Monobloc caliper, specifically with an integral bridge. There have been many discussions and viewpoints about the difference between monobloc vs. 2pc. calipers, forged vs. cast, bolt in bridge vs. fixed. There are even charts that try to describe the stiffness of a variety of caliper to try and tie that into a performance advantage. The bottom line is that there is no such combination that stands out as being better than another. The quality and performance of a given caliper design is more a result of the engineering, development, fatigue and performance testing that goes into the development of the than the actual manufacturing process or materials used.
The design of the new 6-piston monobloc caliper is a direct result of their experience at the top levels of racing combined with experience in OEM manufacturing to yield a caliper that has been tested and proven to offer an impressive combination of structural rigidity for it's given size and weight. The result is a lightweight, stiff, and responsive caliper that offers unmatched quality and longevity in this market. It is truly the closest thing to a full motorsports caliper that has ever been offered to the aftermarket, and done so at a price point that is also unheard of for monobloc performance.
The performance and function of this caliper grossly outweighs the perceived difficulty to remove the caliper for pad changes. I will agree that it is not as quick and easy as an open top caliper, but it is also much simpler and quicker than an OEM sliding caliper and also on par with calipers that require removal of a bolt in bridge. Again, this was a conscious engineering decision based on providing optimum performance. If ease of pad changes is a strong requirement we do offer a stainless steed stud kit to replace the bracket bolts for those of you who track your car regularly. This does help to simplify the process a bit more by having studs to line up the caliper and also makes it more difficult to accidentally cross thread or strip a bracket when changing pads. I have personally changed pads on nearly ever caliper design in use today, and the time it takes for removal of 2 additional bolts is less than the time it typically takes to spread the pistons to the full open position. You can do this task as you lift the caliper off of the disc.
(we will have an instructional video on changing pads in a monobloc caliper very soon)
This brings us to the topic of pads. As with any new pad shape it will take the aftermarket suppliers a while to realize the demand and in turn provide a product to fill the void. The great thing is that these pad manufacturers have already recognized the popularity of the Brembo systems and will respond much quicker than they would for an off brand or OEM production pad shape. There are currently pads available from Ferodo, Pagid, Porterfield, Hawk, Performance Friction, Cobalt Friction, and Carbotech. As the volume and supply increases, the cost for some of these higher end options will also come down. I have a good feeling that by next summer there will not be a popular pad compound that will not be available.
The only way to have sped up this process would have been to create a caliper around an existing popular pad shape. While we have done this in the past, and this is also common practice for many other aftermarket brake kit suppliers, the Brembo engineers again looked towards improving the performance of the system in any way they could. The choice to create a new and unique pad shape was based on creating the ability to combine two very beneficial design traits. This was a combination of a short annulus pad which increases the effective radius (a factor for creating a desired brake torque based on the leverage point, measured from the center of the hub to the center of the pad) and an increase in swept area and pad volume (which directly contributes to improved longevity of both the discs and pads).
The point I'm trying to convey is that with Brembo form definitely follows function. Any of the systems characteristics that have been mentioned in this thread are consciously decided upon based on achieving a level of performance that exceeds that of the OEM system, as well as the vast majority of other aftermarket products available. There may be systems out there with the ability for faster pad swaps, or that use a pad shape that is more readily available today, and there may eventually be one that packages small enough to fit under nearly every 18" wheel, but before you can get excited by those individual benefits you really need to examine what the actual trade off is. If there's anything I learned with my experience over the past 6 years there is always a trade off. The benefit with Brembo is that the trade off never gets in the way of quality, performance, or safety.