The stock-sized Stoptech rear rotors I threw on when I installed the Brembo BBK bugged me and seemed like a half-step. After I was finished with the install, I was consistently reminded of the missed chance to upsize the rears as well. With the larger Brembos up front, the rears looked too tiny and threw off the balance of the car – aesthetically, that is. With the car on jack stands, now was the time to revisit the rears.
Conveniently, the ABS delete’s proportioning valve will be useful to bias out the effects of more leverage in the rear with a larger rotor. The options available for the rear are thin, it was either larger RZ/Spirit-R rotors or Racing Brake’s 2-piece rear BBK. However, the latter was no longer in stock from the manufacturer. I was just about to purchase a set of Spirit-R rotors from Mazda in Japan, when I randomly stumbled upon someone else’s Want to Buy listing for the Racing Brake kit in the classifieds. A member replied stating he had a brand new kit available, so I poached and was able to grab it for myself.
While the deal was initially a good one, it was quickly debased to a degree. One of the aluminum rotor hats had chips and knicks all over, presumably from shipping. The imperfections were likely cosmetic, regardless, I ordered a replacement hat with hardware from Racing Brake. The newer hats feature a slight revision in the design, but all of the fitment dimensions are obviously the same.
In order to fit the larger 12.7″ rotors, the caliper brackets will need to be extended. Racing Brake includes a 1-piece, cast extension bracket, which is strikingly similar in construction to stock. I had to paint these brackets to match the Red caliper bodies.
As an added (possibly superfluous) measure to help with the curing, I baked them in the oven after painting.
2-piece Racing Brakes versus stock-sized Stoptechs:
These rotors feature Racing Brake’s unique Open Slot design, which combine the advantages of both cross-drilled and normal slots. I still need to adjust and fine-tune the bias settings on the proportioning valve, and now probably more than before.