A chainring engages the bike chain to drive power to the rear wheel of the bike. Chain rings have a teeth design to that hook into the links of your bike chain. Chain rings are mainly constructed from aluminium, but also come in steel, titanium and carbon fibre.
Chainrings come in single, double or triple configurations. They can be bought in a variety of ‘teeth’ sizes and they also come in two main formats - PCD's (Pitch Circle Diameter) or BCD's (Bolt Circle Diameter), This is the spacing of the bolts that secure the rings to the crank arms.