This presentation/placeholder brake disk model accompanies this other model of mine:Camaro Wheel (Tire and Rim) Pirelli
The diameter of the brake disc in total is 0.17m. Use scale (in solidworks or your render program) to adjust it to your liking.
STL (Stereolithography, filesize: 82.5 MB), OTHER (Other, filesize: 42.9 MB), SLDPRT (SolidWorks, filesize: 17.2 MB)