A tie rod for motor vehicles comprises a rod constructed of polymeric materials or composites, formed through irreversible chemical reactions whereby the connection is crossed between molecular chains of the base polymer constituent of this composite, reinforced with charges in the form of fibers such as fiber glass, carbon fiber, aramide fiber, among others. These rods are coupled to metallic terminals positioned in their extremities, and this coupling can be made through chemical bonding, such as gluing, for example, and/or mechanical bonding, such as pressing or clipping. Threads may be used for the union of the pieces to obtain adjustability of the length of the tie bar according to its application.