The oversized chainrings are cnc machined from 6mm 7075 aluminium blanks 2mm thicker than the competition unparalleled stiffness is delivered by an increased bolt circle diameter bcd and a two piece insert molded carbon composite construction the xx crank geometry provides a narrow 156mm q factor efficient chainline and beveled crank arms to maximize clearance it39s pure science in action xx chainrings the concept was simple create a geometry that allows each chainring to be divid