A porous calcium silicate by the name of Promaxon®-D has been widely used in friction materials. Especially in NAO/non-steel (ceramic) disc pad applications, Promaxon®-D is an important ingredient of new generations of formulations. Except for its ability to increase porosity, the effect of Promaxon®-D on the friction performance was not well understood. This paper describes the effect of Promaxon®-D on the most relevant friction parameters of NAO/non-steel disc pad formulations.Promaxon®-D is a material which has been observed to be very effective at increasing the compressibility of friction materials. When added in the right percentage, Promaxon®-D can also be beneficial for parameters like friction level, fade resistance and recovery. This makes Promaxon®-D a versatile raw material for NAO/non-steel disc pad applications.