ULTRA RACING Anti Roll Bar. An anti roll bar/sway bar is an automotive suspension device. It connects opposite wheels together through short lever arms linked by a torsion spring. Whenever a vehicle’s taking a corner, the weight transfer will make the car sway a side, causing vehicle body roll and delay in steering response turning into a corner. With Ultra Racing’s front and rear reinforced/bigger diameter anti roll bar, increasing the suspension’s roll stiffness and its resistance to roll in turns, greatly increasing the vehicle’s handling. Please note the image shown is of a generic product.