Direct Drive System, Set: All 22Key Features The Direct Drive System eliminates the slipper for the 22 vehicles, increasing punch and reducing the rotating mass by over 9g or 48% when compared to the standard slipper assembly Specifically designed with new spur gears and hubs, the top shaft is several millimeters shorter than a traditional top shaft to reduce rotating mass The top shaft, and spur hubs are precision machined from 7075 T6 aluminum and hard anodized 69T and 75T spur