A mounting system for performing an installation operation in an elevator shaft of an elevator system has a mounting apparatus that includes a carrier component with a mechatronic installation component, a displacement component, a suspension cable and a deflection roller deflecting the suspension cable between the displacement component and the carrier component. The carrier component is supported against a supporting wall of the elevator shaft by an upper support roller, at least during displacement in the elevator shaft. The suspension cable has, between the deflection roller and the carrier component, a diagonal pull relative to the vertical in the direction of the supporting wall and is guided via the deflection roller such that the diagonal pull can be varied by displacing the deflection roller. The deflection roller is arranged via a holding apparatus on a surface of the supporting wall such that the deflection roller protrudes into the elevator shaft.