Nashbar QR Seatpost Rack. The quick and convenient means to add carrying capacity to your bike is with the Nashbar QR Seatpost Rack. QR stands for quick release and its quick release bracket makes attachment and removal to your seatpost a straightforward, simple endeavor. It works on most any seatpost 25.0 31.6mm in diameter and the rack is stout enough to carry 25 pounds of whatever your heart desires. Built from 6061 aluminum with stainless steel hardware, the Nashbar QR seatpost rack is extremely sturdy and built to last.