Abstract: The normally generally straight, slightly arcuate main leaf of an auxiliary or "helper" leaf spring bundle is modified to include loops at both ends thereof, enveloping the respective helper leaf bracket of the frame, to provide additional anti-sway resistance. The device combines extreme simplicity, particularly in modification of existing suspension systems, for instance when it is desired to use a truck frame in applications subjecting same to extreme canting forces, for instance, in combination with a boom mechanism of a cherry picker device or the like.