Abstract: A brake disk for bicycles has an inner disk, two outer disks and multiple brake units. The brake units, rather than the outer disks, are used to rub with the disk brake pads. As each brake unit is a small lump, the brake units can be easily made of material with high abrasion resistance, high temperature resistance, and low heat conduction, and the brake units still can sustain sufficient strength. With those features of material, the brake disk for bicycles does not deform easily by the heat, and the glue between the outer disks and the inner disk does not melt easily by the heat from the outer disks. Because each brake unit, which is used to rub, is independent from the outer disks, the outer disks can be made of light material, and the whole weight reduces as well.

Abstract: A brake disk for bicycles has an inner disk, two outer disks and multiple brake units. The brake units, rather than the outer disks, are used to rub with the disk brake pads. As each brake unit is a small lump, the brake units can be easily made of material with high abrasion resistance, high temperature resistance, and low heat conduction, and the brake units still can sustain sufficient strength. With those features of material, the brake disk for bicycles does not deform easily by the heat, and the glue between the outer disks and the inner disk does not melt easily by the heat from the outer disks. Because each brake unit, which is used to rub, is independent from the outer disks, the outer disks can be made of light material, and the whole weight reduces as well.