The article considers the rationale for the optimal mineral composition of friction geomodifiers for improving the tribological properties of friction surfaces. The practice of maintenance and repair of automotive equipment can be significantly supplemented by non-traditional tribotechnics for the non-selective restoration of worn-out friction interfaces and prevention of new equipment. The use of friction geomodifiers as an additive to lubricants dramatically changes the friction conditions. (Research purpose) The research purpose is in developing a methodology for selecting the optimal mineral composition for friction geomodifiers to the technologies of maintenance and repair of machinery and equipment. (Materials and methods) The article describes a study of 27 minerals for tribo-compositions using the ii5018 friction machine using the traditional method. (Results and discussion) A statistical analysis of the results of tribo-tests of different mineral compositions was performed to assess the effect of the petrocomposition on the effectiveness of friction geomodifiers...