This dataset contains experimental data as well as simulation data for the study of granular mixtures of hard frictional beads and soft low-friction beads flowing in a cylindrical silo. The data processing is described in readme.txt respectively. The corresponding scripts are included in the folders. The discharge of granular mixtures of hard frictional beads and soft low-friction beads was studied in a cylindrical silo through experiments and simulations. Flow rate depends on fill height for 100% soft grains but remains constant for 100% hard grains. Mixing the two types of grains causes an abrupt transition: adding just 20% hard grains to soft grains changes the flow behavior significantly, it reduces the slope of the flow rate curve by 50-70%. Simulations show that this is due to the stress sensitivity near the orifice. Additional tests reveal increased dissipation with more hard grains, though not enough to explain the sharp flow rate change.