´The drivetrain in the heart of the bicycle. Conventionally we’ve had circular chainrings in the drivetrain.
Oval chainrings changes the overall dynamics of motion. The pedal continues to move in a locus of oval pattern whereas the gear ratio continuously changes making the power stroke more effective and recovery stroke shorter.
This increases the recovery time and deepens the power stroke giving the additional advantage.
Thumbrule:
1.Maximises the strongest part of your pedal stroke.
2.Minimises the weakest part of your pedal stroke.
Advantages of this:
1.Maximum gear ratio in power stroke
2.Min gear ratio in recovery stroke( Faster angular velocity)
3.Gives better efficiency and stroke effectiveness compared to circular
4.Eliminates dead spot in a pedal stroke.
5.Consume less energy at same power output and can ride for longer/faster.
OVAL Chainrings offer approximately:
1.9% increase force effectiveness
2.7% less oxygen consumption
3.15% less ventilation
4.10% less Heartrate
(Source: AbsoluteBlack )