Abstract: The invention is directed to a ventilated disk brake rotor made of integrally cast metal or allow that includes a central hub having a cylindrical main part, and a pair of friction plates extending radially from the central hub in parallel with one another. The friction plates are disposed in mutually spaced apart relationship by use of a plurality of radial ribs. Further, the friction plates are directly attached to an outer circumferential surface of the cylindrical main part of the central hub at their base ends. As a result, the generation of cracks and premature wear are prevented through the increased rigidity of the friction plates without an increase in the weight of the disk brake rotor.

Abstract: A friction material containing 0.85 to 30% by weight of carbon fibers and 2 to 20% by weight of aramid fibers for use as brake pads, brake linings, clutch facings and other mechanical component parts which are subjected to severe frictional contact with other mechanical component parts. The aramid fibers preferably consist of para-aramid fibers and/or a combination of chopped aramid fibers and fibrillar aramide fibers. There is a certain preferred range for the ratio between the aramid fiber content and the carbon fiber content. This friction material offers advantages in a high-temperature stability of the coefficient of friction, a favorable wear property, freedom from sticking and uneven wears, and superior anti-fade properties.

Abstract: A brake disc having a support jaw projecting radially from a cylindrical portion and slide plates attached to the support jaw by integrally formed, radially extending ribs. The wall thickness of the support jaw is less than the wall thickness of the cylindrical portion and the radially inner ends of the ribs are formed integral with the cylindrical portion of the brake disc.

Abstract: A disc brake assembly for the front or rear wheel of a motorcycle including a brake disc having pairs of projections located on its periphery at 120.degree. intervals. The pairs of projections may be placed on either the outer periphery or the inner periphery of the brake disc. The projections define open ended recesses receiving bosses formed integrally with the wheel hub, and partially surrounded by hardened retainers and structural members. A bolt threaded into each boss prevents disassembly of the bosses and recesses but is not subjected to forces caused by thermal expansion of the brake disc during braking. One or more hydraulically activated stationary calipers clamp non-rotary brake pads frictionally against opposite faces of each brake disc. Provisions are made for cooling the brake disc by atmospheric air.

Abstract: Heat insulating materials having excellent heat resistance and durability prepared from glass-ceramic fibers composed chiefly of crystals, e.g., .beta.-spodumene and/or cordierite and containing 0.1 to 15% by weight of at least one metallic element capable of absorbing radiant heat energy, e.g., Cu, Co, Fe, Ni, Cr, Mn, Mg. The metallic element may be in the form of the metal or an oxide thereof and may be present as a film or coating on the fibers.