When I motorcycle roadraced my Ducati I used 13 inch full floating Brembo cast iron rotors on aluminum carriers. Bike was making 120+rwhp and weight was 400# with 150# for me. The rotors were covered with holes and never had any problems.
I have noticed that many people are strongly against holes in car rotors. What is the problem? Is it a weight induced cracking issue?
Very good question. To our knowledge most motorcycles rotors are made of 400 series stainless steel, the disc is hardened (for wear resistant) and mirror polished (for the look). Stainless steel has good strength but has very poor heat dissipation and dumping capacity due to its very low carbon contents (less than 0.2%). A lot of holes are added to the discs mainly to increase the biting edges (friction) and cooling surface than for weight saving. Some mfgrs use ductile iron which is a better material for heat handling and stronger than gray iron but it?s subject to rust and therefore are not acceptable to most mfgrs and users.
So the ideal brake material for motorcycles is to have good strength and will not rust. We made discs for a major custom motorcycle mfgr with Compacted Graphite Iron (CGI) with excellent balance of heat handling and strength but as a nature of iron the surface still would rust so this project was not further pursued, while our CGI rotors made for SCCA club racing
have won a great success. As far as we know RB is the first and only brake company that makes the motorsports rotors with CGI material.
Carbon (graphite) is the most essential element in cast iron casting not only by percentage like other metals, but by the type of graphite (I-VII), and out of type VII (flake graphite) it?s sub classified to 5 types (A-D) dealing with the flake distribution and flake size (graphite length). Mold design, casting process can affect any of these graphite formations which predominately dictates the quality of a casting. Learn more...
So when we evaluate the quality of a casting we first look at its microstructure (how graphite is formed under microscope) than any other criteria. Carbon is the known to be the best substance for heat handling. RB two piece rotors are made with higher carbon contents than standard G3000 gray iron, and we added alloys to make up the loss of strength due to the increase of carbon. RB two piece racing rotors have been proven in the race tracks to have outperformed the competition (provided the proper pads are used) and out last most major racing brake pads.
Most of the drilled rotors are made from stock blank which is meant for street driving that could be more prone to crack under severe braking however, in our opinion, it was purposely demoted by a brake company who promotes solely on slotted rotors (http://www.powerslot.com/images/deal...cked_rotor.jpg
Look what motor companies like BMW did on M3 E46 competition rotors
, Porsche, Mercedes, GM (C6 Z51 and Z06) and Brembo front two-piece rotors for Corvette Z06
they all supplied with drilled rotors. Contrary to most common belief, the crack was more attributed to how well can a rotor material handle the thermal stress than how strong (more material) is of a rotor, in other words it?s more of a heat factor than strength factor.
RB makes various disc finish available and we only present the facts with pro & cons
for customers to make their own choice without bias.
All RB brakes carrying with our money back satisfaction guarantee for the performance, durability, low maintenance or replacement cost and look.