Purpose Among the components used for a car brake lining, the chemical and structural properties of the abrasives, jointly with the morphology and size of the particles influence the friction parameters and stability of the composite. This paper aims to investigate the effect of nano SiO2 particles in brake pads on friction and wear properties. Design/methodology/approach In this paper, the effects of SiO2 (Silica) particles of varying size on the friction-wear properties of polymeric friction composites are investigated. Four friction composites were prepared containing (5, 10 Wt.%) micro silica (MS) particles and (5, 10 Wt.%) nano silica (NS) particles. The samples were produced by a conventional procedure for a dry formulation following dry-mixing, pre-forming and hot pressing. Friction and wear characteristics of the specimens against to a disk made of cast iron were studied. Friction coefficient, specific wear rate and hardness of specimens were obtained. Detailed examinations on the worn surface were analyzed using a scanning electron microscope. Findings The results of test showed that the inclusion of nano silicon carbide (SiC) powder improved the wear performance significantly. Friction coefficient (μ) of NS samples was higher than the MS samples. Micro-SiC showed poor performance and μ. High wear performance was exhibited in materials containing 5 Wt.% NS and 10 Wt.% NS. Originality/value This paper emphasizes the importance of nano-composites in the automotive industry and helps to industrial firms and academicians working on wear of materials.