楼主过虑了，铸铁是主流，钢的轻易变形，夹心的光纤的也有。太薄不是指贴层太薄就是总厚度不够

https://carfromjapan.com/article/car-maintenance/what-are-brake-rotors-made-of/

conventional automotive brake rotors are cast from G3000 grey cast iron. These work well with a pad material designed to operate using adherent friction. Most of the European system rotors are cast from a high carbon G4000 grey cast iron.

不觉得普通日车会用夹层。