Why are there grooves on some discs? Are the brake pads hard?
There are national standards for the hardness of brake pads, which are basically between 35 and 70 Shore hardness. This hardness is not the main cause of wear on your brake discs. The wear-increasing agent in the brake pads is the main component of the wear disc. Among all the three formulas, the most abrasive to the disk is not the semi-metal with high metal content that we often see, but the low metal with little metal content, that is, the kind with a lot of dust and large particles on the outside, ceramic minimal wear and tear. Then why do you see that the disks of Mercedes-Benz and BMW are very flat? The reason is that the brake pads of the original car cover have a very fine, uniform, and high-purity abrasive, so it wears the disc a lot, but it is very uniform, similar to fine sandpaper polishing. And everyone sees the brake pads that are ground with grooves because the abrasives in them are of different sizes, and the purity is soft or hard, just like grinding a disc with a coarse grinding wheel, the surface of the disc will naturally be uneven. And these will greatly reduce the cost, but the effect is not the same. Therefore, the soft and hard brake pads are not the reason for the serious wear of the disc, but the low-cost wear-increasing agent is the culprit.
