Abstract: A crank arm for a bicycle crank arm system has an elongated hollow core (30) made of a first fiber-reinforced plastic and having, in the final assembly position of the pedal crank system, a laterally located, exterior front face, a rear face opposed thereto and two side faces (102) that connect the front face and rear face with one another, and having at its axial ends (104, 105) metallic shaft sleeves (20, 22), oriented parallel to one another and to the side faces (102), for accommodating a bottom bracket shaft or a pedal axle. The hollow core (30) is encased by a second fiber-reinforced plastic. A carbon fiber thread (50) is wrapped multiple times axially around the hollow core (30) and is in contact with the axially convex side surfaces. The hollow core (30) is bonded to the carbon fiber thread (50).