The stabilizer is a device mounted to the vehicle body in a rocking manner. The ends of stabilizer bar arms are connected to the chassis elements. The central section is connected to the body by means of two radial bearings. The free ends (arms) are connected to suspension arms or suspension struts with short, bi-articulated bars. Stabilizer may be mounted either on the front or rear axle, or on both axles. Classic stabilizer is a U-shaped tube or rod of circular cross-section, made of spring steel and is characterized by a constant stiffness. In stabilizer bars referred to as active it is possible to change the rigidity. This allows to adapt the characteristics of the stabilizer bar to other components of the vehicle suspension, depending on the motion parameters it’s possible to influence the vehicle’s safety and handling, as well as the comfort of the driver and passengers. The article presents selected solutions of mechanisms and systems, whose role is to change the stiffness or tension of the bar. It also outlines the concept of stabilizer bar tension changes developed at the Department of Vehicles and Fundamentals of Machine Design at Lodz University of Technology.