Warning: put on your thinking cap and read carefully! Heavy Tech info to follow!
 
This article is written by Marcus di Sabella and DOES reflect the feelings and opinions of Heeltoe Automotive! I am a college graduate from California State University in Long Beach in the Manufacturing Engineering Technology program. To the best of my ability I am being accurate in my articles, and corrections and comments are welcome. I am going to link to Racingbrake's site a lot, and provide some other links later. These should serve as my references in lieu of preparing a reference list.
 
There are a lot of reasons to choose Racingbrake over just any other OE replacement rotor available. The main reasons are:  
1- Material  
2- Molds  
3- Process.
 
Before I outline these points I should make it clear that Racingbrake produces their own rotors. They are in control of their product. They don't buy parts from other companies and have them modified or upgraded. These rotors are made from the ground up with Racingbrake's vast engineering knowledge. Racingbrake produces a few different types of rotors: HP, UP, Two-Piece, XP, and Two-Piece rotors. The basic rotor is the HP, and all of the following applies to this rotor. The other rotors are upgraded from the HP, and I will call out the additional features as they come up.
 
 
1- Material
 
1.1- In order for brakes to work well, the rotors need to be able to absorb heat, and then dissipate it. I'll get into dissipation in a bit. The ability for a rotor to absorb heat really does depend on the material the rotor is made out of. More material will hold more heat, but it would also weigh more. Racingbrake overcomes the need for greater thermal capacity without increasing volume or weight through their metallurgy. Specialized metallurgy is the main advantage of choosing Racingbrake.
 
1.2- Your typical brake rotor is made out of cast gray iron. Inexpensive to produce, able to withstand high temperatures, and with excellent vibration dampening properties this is the preferred material. However there are many ways of producing any given metal, and brake rotor material can be alloyed to give it varying properties. Of course, you have acceptable on one end of the spectrum (read: "meets OE specifications"), and you have superior on the other end. OE specifications are intended to produce rotors that have a certain hardness rating with a certain carbon content and able to withstand a certain amount of thermal expansion without cracking (tensile stress).
 
1.3- If I am trying to replace my brakes, I think my bare minimum requirement would be that it "meets OE specs." That same spec would not suffice if I wanted to UPGRADE my brakes. Racingbrake rotors are made from a material upgraded from the OE standard (Racingbrake Site). This is the main factor differentiating Racingbrake from other brands. Many of the "performance" rotors you will find available today (you know, brand B, P, R, and S) are made from conventional gray iron.  Chinese and Taiwanese suppliers to "performance" alternative brands are capable of producing acceptable rotors, but do not take care to produce the most refined product available. Consistency is generally very poor as well. And the major problem encountered with competitors’ rotors is that they buy rotor blanks from manufacturers, drill them, slot them, paint them, and sell them as performance parts with fancy marketing. In fact, the rotors you are expecting to be an upgrade from stock may not even be meeting OE requirements! My stance is not that other companies cannot produce great rotors. It is that you don't know a good rotor from a bad one, and you need more than a brand name to trust.
 
1.4- If the casting process is not carefully controlled, the iron may not form the proper microstructure resulting in a noisy rotor or one that lacks proper hardness. A rotor that is too hard may crack while one that is too soft may wear prematurely. Again, economy rotors may not be made to the same level of quality as premium rotors ( L. Carley, 2006). It is a fact that the material microstructure has an effect on wear resistance in gray irons (SAE, page 64). Racingbrake knows this, and produces their rotors to have the best available uniformity of microstructure and thermal capacity by incorporating specific alloys into their material. This important difference in Racingbrake's added alloys is used to improve on the SAE standard G10 material (Racingbrake Site). With a higher carbon content in the material the Racingbrake rotor is able to withstand higher temperatures than a normal rotor without the risks of cracking and warping that other rotors can experience. A known property as published by the Society of Automotive Engineers (SAE) states that as carbon content increases, hardness is decreased (SAE, page 60). But Racingbrake in their infinite casting abilities have formulated a highly specialized alloy to counteract the softening effect of higher carbon content. Altering the metallurgy of a casting has a big effect on the outcome of the microstructure. Other manufacturers do not go to this extent of material selection and manufacturing process because they simply are not in the market of producing a part that is built for quality and performance from the ground up. Racingbrake is.
 
1.5- My last comment on material has to do with the subject of cross drilling. There seems to be an awfully big backlash against cross drilling recently. The general claim is that they are more prone to cracking because the drill holes act as stress risers; a place for cracks to start. Well, in most cases, where junk rotors are prone to cracking anyway, I would definitely agree that drilled rotors are going to propagate cracks more readily. All too often we have companies buying cheap blanks and boring holes in them all willy-nilly. In the case of a rotor such as a Racingbrake, the rotors are designed to be able to handle drills being put in them. The material, as stated, is less prone to cracking from the get go, and is therefore less crack prone when drilled. Cracking is not nearly as significant an issue with Racingbrake rotors as it is with inferior brands. That is because the RB material is made for performance duty.
 
1.6- Cross drilling. Is it only for looks? Does it cause cracking? It used to be effective at degassing but this benefit no longer applies? Reduced surface friction or heat capacity? AMG, Porsche, etc use them, they must be good! Racecars don’t use them, they must know something! Well, I think there is a time and a place for everything. If you are using pads that produce a lot of dust and gas, use the rotors. If you need a rotor that is able to withstand high heat fluctuations over a long period of time, stock with a blank/slotted rotor. Need to save weight? Drill. Optimize friction forces? Solid. I think it is ridiculous that people try to pigeon-hole products by making broad statements. Get the product that suits your needs. And if the rotor performs the way you want but you need to replace it more often, then you have found a performance trade-off.
 
1.7- On a note for an interesting piece of Racingbrake Two-Piece rotor development, they have broken ground with the Open Slot design.

This patented design has all the benefits of slotted and drilled rotors without the compromise in rotor integrity (since these rotors are specifically designed to have holes in them) or friction surface loss. Read more about drills and slots here.
 
Enjoy more wear resistance and dramatically less cracking with Racingbrake rotors!  
 
XP and Two-Piece Rotors:
 
1.8- It should also be noted that Racingbrake, in an effort to choose the highest performing materials in their racing-spec rotors is producing a compact graphite iron (CGI) material for XP and Two-Piece rotors. This compound is one where the graphite in the solution is in the shape of flakes (similar to gray iron) but has rounded edges (similar to ductile iron) (ASM International, page 19-22). The advantages over gray iron are significant in that these rotors are less prone to cracking due to the reduction of microscopic stress risers, and they also provide a greater friction coefficient (G. Cueva et al). The same braking torque can be attained with the less pressure. Rotors made from CGI are highly effective for performance use because they are very durable, they can withstand higher temperatures, and they provide a greater braking torque from equal input force than gray iron rotors!
 
 
2 - Molds
 
2.1 - Because Racingbrake designs and manufactures their own molds, they are able to enhance the design of their rotors beyond the conventional OE replacement or alternative "performance" brand.  
 
2.2 - By producing proprietary molds, Racingbrake is able to incorporate enhanced design features into their products. Two major casting specific enhancements are incorporated in Racingbrake’s offerings. One is the use of reinforced ribs:

With alternating rotor vanes extending beyond the ventilated region to the center hub area, the vanes are able in enhance their heat dissipation ability, have a higher heat capacity, and are able to resist warping through increased rigidity. This patented design feature is a major improvement over conventional designs.
 
2.3 - On the Racingbrake UP and Two-Piece rotors, straight vane designs are eschewed in favor of vanes that are curved. Similar to a fan blade or airplane propeller prop, a spinning blade that is curved in an aerodynamic fashion will move more air. Similarly, the curved vanes in select Racingbrake rotors will provide a great deal more airflow than a conventional design. Also of note is that a curved vane will be directional, thus requiring a left and right mold be produced to manufacture one set of brake rotors. The extra tooling costs needed to produce these rotors should serve as an indicator of Racingbrake’s desire to produce the best rotor available, not simply the best one that can be made at a low cost. This curved vane feature alone is enough to set Racingbrake apart from the competition, forgetting all that we have covered and all there is yet to cover. This feature is truly significant.
 
2.4 - Casting is all about flow, temperate, time and in some cases pressure. Racingbrake brake rotors feature a center-split casting to provide proper heat transfer through the vanes. As heat is generated on the friction surfaces, it is transferred to the inner vanes where airflow removes the heat from the rotor. If the rotor is cast in one piece, material flow through the mold will not allow the molten substrate to fill the cavities of the rotor optimally. By producing the rotors in two pieces and attaching them together at the centerline of the cooling vanes, material can be evenly distributed throughout the rotor and will solidify optimally forming a uniformly distributed matrix.
 
2.5 - You know Racingbrake is in control of their own molds and castings because their name, lot number, part number, and minimum thickness data are CAST into the rotor hat. This can only be done as the rotor is manufactured. You can install your rotors with confidence that they were not produced in an unknown facility and engraved with identification numbers. This proof of genuine OEM article is not available in the competition's rotors. Truth be told, when you buy a rotor without "iron clad" identification, you don't know what you are getting. This feature allows Racingbrake to address quality and manufacturing issues, right down to the date of manufacture. Traceability is a key factor in a company’s ability to monitor and control quality. Without ID numbers a manufacturer cannot trace warranty complaints and follow through with legitimate product improvement measures.
 
2.6 - I will take this opportunity to attempt to expose a myth in the rotor world. There is a common misconception that when high caliber (Porsche) drilled rotors are made, the holes are actually produced in the casting process. If there is any proof of this then I would love to see it. I can’t even begin to fathom the issues that would be raised in the material flow though a mold that had provisions for these holes. I can see it being done, but getting the material to solidify evenly and optimally would be extremely difficult. There would have to be an awfully expensive process needed to make rotors with holes cast in them properly. I am not beyond the notion that it exists, but I would like to see some proof that is not conveyed in the form or hearsay in some message forum posting.  
 
2.7- Two-Piece Rotor Castings incorporate a center mount design.

The alternating tabs on the rotor allow air to travel into the vanes equally in the front and rear of the rotor hub. The heat generated in the rotors is also more evenly distributed in the front and back friction faces. Overall these rotors will stay cooler than a one-piece rotor, allowing more aggressive compounds and high brake pressure. Racingbrake can only accomplish this patented design with the use of their own molds. No other manufacturer offers this feature. These two-piece rotors are really one of a kind.
 
 
3 - Process
 
3.1- As mentioned before, Racingbrake rotors are designed from the ground up by Racingbrake to be the best rotor you can buy for your car. Concepts are incorporated into 3D graphics software where tolerances, fitment, and critical design elements can be incorporated. This design process allows Racingbrake to virtually test the rotors before they are produces to expose weaknesses.  
 
3.2- Casting is the preferred method for producing iron in complicated shapes. But true casting is an exact science; more than just melting metal and pouring it into a mold. Solidification rates, hot and cold spots, consistency, and uniformity are all important factors to consider when casting a part. The complications compound when multitudes of alloying elements are introduced into the melt. It is Racingbrake's superior knowledge in the area of casting that allows them to obtain the optimal microstructure for their parts. Racingbrake is a division of TPM products, who as been a manufacturer of cast and forged parts for over 20 years (About TPM Products). Highly specialized casting methods are required to obtain a quality product with such a specialized material. Racingbrake is proficient in those methods.
 
3.3- All non-friction surfaces on Racingbrake rotors are coated with an Electro-Deposition Paint (EDP) in order to prevent unsightly rust from developing. Coating rotors is nothing new, but the particular process used by Racingbrake is actually applied to the entire rotor surface after all machining takes place. Slots, drill holes, hub area, even inside the vanes; all areas are coated. A final cross cut finish is applied to the friction surface to clear the paint and promote better pad bedding. The EDP coating used by Racingbrake is environmentally friendly and highly effective at preventing corrosion.
 
3.4- Speaking of machining, this is another process than Racingbrake takes pride in. Final cuts are made with the help of NC technology to obtain tight tolerances. .004” and .002” are common tolerances used in all Racingbrake applications. These tolerances are important to know because they will provide insight into the proper specs of the rotors. Without knowing these specs, inspection of the rotors at a later time will not reveal specification compliance. Other manufacturers do not provide the specs they strive to meet (beyond claiming meeting obscure OEM specs). Racingbrake rotors carry a 1 year warranty against warping or manufacturer defect. Now you know they have a tight spec to measure against when approving claims.  
 
Racingbrake UP Rotors
 
3.5- One more hugely significant process used in producing curved vane UP rotors is a heat treatment process. I spent a good deal of time studying heat treating in college and when I heard that these rotors were heat treated my eyes got wide. Heat treating is a very broad subject, and I am going to simplify it in the interest of maintaining your attention.  
 
3.6- When a casting is made, molten metal pours into a mold and solidifies into a metal shape. Despite modern technology and methods, it is very difficult to get the metal to solidify properly, with a consistent distribution of material throughout. Some areas cool faster than others creating regions of misshapen microstructure. “Microstructure” is a general term for the tiny bits of atom chunks that are built up to form the material of the rotor. The size and composition of these chunks affect the overall properties of the material. Inconsistent material is unstable at heat, and is prone to warping and cracking. So, we heat treat to gain a microstructure that is ideal for our needs, and consistent throughout.
 
3.7- The rotors are brought up to a critical temperature which allows them to “melt” without liquefying. By bringing the material to critical temperature and quenching it to a lower temperature, a different material hardness and microstructure is attained. But it is important to know that heat treating is tricky and the formula for performing the process ideally per your material and intended properties is difficult to obtain. A material may be heated, held, quenched incrementally 3 times to reducing temps, then heated again and air cooled before it is done. The heating and quenching temps and the hold times at these temps are all variables that can be manipulated to get the best material in the end. And this speaks nothing of the alloy being used, which must be specifically formulated to respond to specific heat treat processes.
 
3.8- Heat treating will also relieve latent thermal stresses in the material. Due to uneven cooling in the mold, some areas of the material will contract at different rates than other parts creating internal stress within the material. While most brake rotor makers will allow this stress to exist, thereby promoting the possibility of stress cracks after repeated heat cycling, Racingbrake’s heat treat process will alleviate these stresses.
 
Yes, as you may have guessed Racingbrake has done all of this homework for you in order to create, all say together, the best OE replacement rotors available.
 
Racingbrake Two-Piece Rotors
 
 3.9- In Racingbrake’s Two-Piece rotor lineup, carrier hats are produced from aluminum to reduce weight, improve airflow, and reduce deformation under high heat. What makes these hats significantly better than other two piece rotors is that they are produced from forged aluminum rather than conventional billet aluminum. Forged aluminum is much stronger and will not deflect under the forces of braking. Investing in high quality yield processes like forging is another reason why Racingbrake rotors are superior to all others.
 
3.10- In the assembly process, Two-piece Racingbrake rotors utilize high end self locking nuts that do not require the use of loc-tite and will not produce rattling noises. The rotors and hats are fastened in a floating method, which enables the rotors to expand and contract with heat. Other brands may avoid the floating type mounting because of production process constraints or reduced cost.
 
 
 
Conclusion
 
If this all sounds like Racingbrake propaganda, well, it is. I have to admit, I have been selling car parts for 10 years, and specifically performance parts in the last 5. I never promoted an aftermarket brake rotor until I met Racingbrake. I firmly believe in them, have made many customers happy with them, and will continue to do so as long as they have the best brake parts available!
 
Marcus di Sabella
Heeltoe Automotive
8/15/07