Grooved carbon brake discs

A disc brake having a stack of alternate rotating and stationary annular discs having torque transfer notches therein extending across the full width of the disc carried between a backing plate and a pressure plate, said discs operating in the earth's atmosphere, comprising:

• each annular disc being of substantially uniform thickness across their full width and formed of a carbon based material capable of absorbing water and having a plurality of grooves extending across at least one of the rubbing faces of the disc, each groove extending the full distance between the inner and outer peripheries of the disc to transfer water-based steam and vaporized gasses emanating from the disc material from between adjacent discs caused by heating during a braking action, the grooves being located at spaced intervals around the disc, each groove in at least alternating discs extending at a large angle from a radius thereof.