Chainwheels & Rings
Chainrings also called chainwheels or "sprockets", although sprocket is used this way mostly in the BMX community, engage the chain to transfer power to the rear wheel. They have teeth spaced to engage every link of the chain as it passes over; however, in the past, some designs (called skip-tooth or inch-pitch) have had one tooth for every other link of the chain. Chainrings vary in size from as few as 20 teeth to as many as 55. Chainrings are constructed of either an aluminum alloy, titanium, steel, or carbon fibre.