A deflector pulley is an idler wheel that changes the direction of the suspension ropes between the traction sheave and the car or counterweight, without transmitting drive torque. It is used to achieve the correct rope drop distance in the shaft when the sheave position does not align with the hitch points. Unlike the traction sheave, a deflector pulley has rounded grooves that minimise rope wear, and its diameter must respect the minimum sheave-to-rope diameter ratio set by EN 81-20.