Tuberous roots obviously benefit in comparison with other feeds, due to the high level of specific volume energy, productivity and good digestibility. When they are mixed with other components, the palatability of finished mixtures for animals increases. The quantity of digestible nutrients in tuberous roots can reach up to 90%. To make the nutrients more fully digested by animals, the correct preparation for feeding is necessary, including chopping. One of the problems of roots cutting process is the increased exudation, which results in undue losses of vitamins. Therefore creation of choppers providing the required quality of finished product is a crucial task. The aim of the research is to determine the optimum angle of inclination of the wall of charging hopper depending on the size of tuberous roots and on the offset of horizontal knife of a chopper. Brief description of the developed chopper of tuberous roots is given, as well as the sources of information containing the detailed description of the installation and its operation principles. In the process of theoretical calculations, the scheme of all forces acting in the moment of tuber pinching between the wall of charging hopper and the horizontal knife is drawn; the chain of discourse and theoretical reasoning are shown in detail. As a result of calculations, the analytical dependences are obtained through which assigning the thickness of slices and sizes of chopped tubers, it is possible to calculate the desired inclination angle of wall of charging hopper. Under estimated values, the tuber does not roll over the cutting knife, and the deformation is minimal. Therefore the exudation decreases, and nutrients losses are minimal. On the basis of the derived dependence, the graphs and their analysis are given.