In a compressor and turbine wheel for a secondary air feed device formed as a single component, a rotor which includes a center disc structure consisting of at least two discs of different materials is provided at one side with compressor blades and on the opposite side with turbine blades, and the discs consist of an alloy based on Al, Mg, Ti, Fe, or Ni and are preferably arranged in axially spaced relationship with a disc carrier of a plastic material disposed in the space between the two bladed discs.