Complex studies of the mechanical properties of composites based on rubber vulcanizates with various micro and nanofillers (which are already used or intended to be used in the tire industry) were carried out. Testing of composites for uniaxial stretching to rupture allowed us to determine the reinforcing effects of the input of fillers, as well as materials strength and deformability. Cyclic tests for biaxial loading in two mutually perpendicular directions were also carried out. As a result, the effects of softening and the occurrence of induced mechanical anisotropy in filled elastomers under the action of a biaxial load were studied. It was shown that there are no hysteresis losses in the unfilled elastomer, and there is no induced anisotropy. For a filled elastomer, the value of hysteresis and induced anisotropy depend on the type of filler, its concentration and particle size.