Also called chainwheels or sprockets, these are the rings with teeth that engage the front of the chain near the crank arms. Usually you have three. The smallest is called the "granny gear" as it is the easiest to pedal. The largest is for top speed, and also is contacted during log hopping and occasionally on rocks. The size of the large chainring can affect the ground clearance. A good quality large chainring is mandatory for rough trails and rocks and logs (trust me - I know). One that bends should be replaced and upgraded. You can select different rings with different numbers of teeeth to alter your gearing.

1: The set of toothed rings (usually three) that are bolted to the right crankarm. 2: An integral part of the drivetrain, as the chainrings move the chain.

The gears on the front of the bike, surrounding the pedals.