a flexible composite torsion shaft for attachment to a drive shaft includes an elongated core element having a circular cross section . a reinforcement comprising at least one polymer layer and multiple layers of reinforcing - fiber wound around the core element inside the at least one polymer layer . each reinforcing - fiber layer is wound around the core element at a winding angle in a range of 40 ° to the hoop winding angle , depending on a width of a reinforcing - fiber being wound , relative to a longitudinal direction of the core element . at least one reinforcing - fiber - layer is wound at an opposite angle from another reinforcing - fiber layer inside the at least one polymer layer . the winding angle increases as an average layer diameter of reinforcing - fiber insider the at least one polymer layer increases .