Linear block-polyurethanes (BPU) are finding more and more practical applications in industry, and their recipe range is rapidly expanding. It is shown that the evaluation of the tribotechnical characteristics of BPU depending on hardness, as suggested by ISO 16365-1:2014 P1, is inaccurate and requires further research to establish the relationship between structure and properties of polyurethanes, taking into account their chemical structure and the type of initiaal components. The dependences of the tribotechnical characteristics of linear block-polyurethanes under friction with steel without external lubrication and in the liquid on the parameters of structural organization of the polymer were studied: at the molecular level (oligooethers, oligoesters), at the topological level (change in the molecular weight of oligomers from 500 to 2000), at supramolecular level (influence of crystallinity), at the morphological level (content of hard phase). The change in the roughness of steel counterbody during friction of polyurethanes with the content of hard blocks 20%, 50%, and 70% was also studied. A method is proposed for increasing the wear resistance of polyurethanes by thermal diffusion saturation of the surface with silicon carbide particles.