Application: Rear 1990-93 Miata - RacingBrake's direct replacement slotted and cross drilled rotors for the 1990-93 Miata offers a great performance upgrade at a very reasonable price. Combine these rotors with an upgraded performance brake pad and experience even greater levels of braking stopping power! Priced and sold per pair.
Making a selection of an aftermarket performance rotor set can be a challenging task with the wide variety of components available on the market. Just how are you supposed to know what is best for your Miata? Since our introduction to the RacingBrake product line (and visiting their local headquarters and meeting their staff) we've been extremely impressed with their design concept, overall product quality, and customer support. To answer some of your more popular questions, we've provided the following information directly from RacingBrake:
Part Number: 9197R-141
Size: 231x9mm (9.1" x 0.4")
Rotor Weight (lbs.): 5.6
RacingBrake - We make real performance rotors from the ground up. First comes design. A CMM is used for precise measurement, then 3D computer modeling is used for design with improvements to make up the shortfalls of OE design and for performance enhancement. The following examples are proof of our superiority to OE or competition.
Curved Vane- Some of our ventilated rotors are selectively upgraded from OE straight vanes to curved vanes as we deem necessary for performance, as most people are aware that curved Vanes pump more air and keep discs cooler than straight vanes. However, curved vane discs are "directional," meaning that the left and right discs are different and require two sets of tooling at the factory. Straight vane rotors can be made from the same single set of tooling. We spend more time and money in extra tooling. Our products are based on performance needs, not just cost. We invite you to check around in the performance market and see if any manufacturer offers the same upgrades as RacingBrake.
Production Material- Our rotors are made of material upgraded from the OE standard of SAE J431 Class G3000 (30,000 psi in tensile strength, 187-241 in Brinell hardness). More important is our know-how and experience over decades in cast iron metallurgy. All rotors may appear the same but under a microscope there is a world of difference in metallurgical structure, which per ASTM A-247 the type (shape) of graphite shall be VII or flake graphite with "A" type uniform distribution and random orientation, and graphite size.
These are published data but achieving the optimal casting requires years of metallurgical experience and precise control during the casting process. Carbon (graphite) contents and structure greatly dictate the mechanical property of the cast iron for a brake rotor. Brake rotors are subject to sudden and extreme heat load cycles while a is braking. Proper material and casting can help a rotor perform optimally and be more resistant to wear, without warping or cracking.
Heat Treatment- Severe brake duty cycles require not only good material but need proper heat-treatment to relieve the residual stress and further enhance the microstructure uniformity. Over the years, we have developed a proprietary process in temperature and time control to achieve the optimal result.
Machining - All of our rotors are machined by advanced CNC to a general tolerance of ±.004" and ± .002" for critical dimensions such as parallelism, thickness variation and indicator run out. We claim our tolerance in figures rather than phrases such as "tightest in the industry," like the competition does. These tight tolerances are our best assurance of fitment, easy break-in and demanding brake performance without pulsation or vibration.
Finish Coat - Rotors are subject to rust, and most rotors are not protected against corrosion in early years. It is not uncommon to see a rusty rotor on a car dealer's brand new show car. When we started our performance line about four years ago, we tried and experimented with various surface coatings, and found EDP (Electro-Deposition Paint) gives the optimal result in durability and cost. Not only does EDP provide lasting protection against corrosion (lasting about 500 hours in a salt spray test, vs. 100 hours for common bright zinc plating), it has an appealing black look. In addition, it is environmentally friendly, unlike the cadmium or gold zinc plating (which uses hexavalent chromium) used by the competition. Identification- We stand 100% behind what we make. All RB rotors are cast or imprinted with: TPM (company name), 9004 (Our P/N), MIN THK 22.0 MM, Lot# for identification. Our rotors also have an engraved direction arrow, where applicable, to assure error proof installation (Even slotted straight vane rotors are directional). These marks are not just for identification. They are your assurance and our symbol of quality racing components.