Patent ID: 8894523

Claim:
A chainwheel comprising: a chainwheel body being round and comprising a center point; and a periphery; multiple chain teeth arranged along the periphery of the chainwheel body; a first combining hole set formed through the chainwheel body and comprising multiple first combining holes that are formed through the chainwheel body, wherein each first combining hole has a center point; a first distance is defined between the center point of each first combining hole and the center point of the chainwheel body; and the first distances between the center points of the first combining holes and the center point of the chainwheel body are equal; and a second combining hole set formed through the chainwheel body and comprising multiple second combining holes that are formed through the chainwheel body, wherein each second combining hole has a center point; a second distance is defined between the center point of each second combining hole and the center point of the chainwheel body; the second distances between the center points of the second combining holes and the center point of the chainwheel body are equal; and the second distance is longer than the first distance.