Every sprocket tooth has been designed to achieve the maximum synchronization, shifting speed, and silent operation. The six larger sprockets have a double frame system for extreme torsional stiffness, so that operating precision is maintained even during shifting under stress. The surface treatment of the eleven steel sprockets assures longer component life, maintaining the maximum performance through time. The Athena groupset uses the Chorus sprockets. Sprocket synchronization provides improved shifting precision with less stress for the chain Ultra-Shift tooth shaping provides upshift optimization Nickel-chrome surface treatments on steel cogs for longer life and lower wear Light alloy lock ring for weight savings