In absence of external torque, plasma rotation in tokamaks results from a balance between collisional magnetic braking and turbulent drive. The outcome this competition cooperation is essential to determine the flow. A reduced model, supported by gyrokinetic simulations, first used explain quantify only. ripple amplitude above which drag overcomes viscosity obtained. synergetic impact on toroidal Reynolds stress explored. Simulations show that main effect comes an enhancement radial electric field shear ripple, turn impacts residual stress.