Abstract: This invention is applicable to bicycle non-circular chainrings or ovoid chainrings, attachable to a drive crank arm with a spider, forming a structure with anchorage points distributed in a star like shape; the said ovoid chainring (1) having a major diameter, whose angle with the said crank arm measured in the pedaling direction defines its orientation; whereas, said ovoid chainring has a number of anchorage points to said spider which is a multiple of the number of anchorage points of the spider, constituting multiple anchorage options to this crank arm, separated in such a distance that respective orientation values differ in 3°; and for such a small variation, the proposed constructive solution is equipping the ovoid chainring with consecutive overlapped holes and respective countersinks with different depth, forming stair steps which help supporting tangential loads to the chainring.