MTB

Rotor Q rings are oval chainrings that will help you to pedal more smoothly. Nonsense? Certainly not! It's actually quite logical: When you have the most power, the position on the big picture below, the Q ring is slightly larger than at the dead spot*. That gives you a little more power than circular blades. See pictures below.
         
Spinscan round chainrings left compared with Q Rings right.
 
On the first picture the spinscan indicatetes very clearly that at the deadspot there is (in this case) no performance at all.
The second picture a typical image of a spinscan from a rider who uses Rotor Q Rings.

Paradoxical as it sounds, but pictures above proves: "With Rotor Q Rings you will pedal rounder than with round blades "

* The dead point is the part of the rotation between "twenty-five past" and "twenty-five to"