An assembly for use as part of a vehicle suspension system includes an adjustable roll rate that is automatically adjusted responsive to maneuvers of the vehicle. A stiffener element is coupled with a stabilizer bar. The stiffener element increases the roll rate responsive to the vehicle wheels being turned. In one example, the stiffener element is a metallic plate that rotates into various positions responsive to the vehicle wheel being turned. The further the wheel turns, the further the plate rotates and the greater the increase in the roll rate.