an adjustable anti - roll bar having a single set of mounting apertures whose roll rate is adjusted in the middle of the anti - roll bar . the roll rate is determined by the location of the junction of one torsion member to another ; that is , an outer torsion member to an inner torsion member . in order to account for the presence of certain automotive components in the undercarriage area , the geometry of the anti - roll bar may be changed . the second embodiment meets this challenge for a specific vehicle by using two weldments of a specific size to relocate the adjustable middle section . changing the length and angle of the lever arms of the first embodiment can do the same thing in many instances .