He has used that chainring for several years, it is called an Osymetric. French made, hard to find.
The premise is, a rider pushes a higher gear on the downstroke and a lower gear when in the 12/6 dead spot position, allowing the rider to spend more time in the power phase and less time in the dead spot area/void.
For 2006 Rotor is developing what we think is an improved version of the Osymetric, called the Q-Ring, which has several bolt holes and is completely adjustable for each rider's unique power stroke. The chainrings will fit any 130/135mm BCD crankset, e.g. Dura-Ace, FSA and Campy.
Initial testing using SRM power meters shows lower heart rates at the same power production (which is great for endurance athletes). I have been on a couple prototype systems for about a month and love them, the production Q-Rings are coming in a few weeks and we will be taking our time testing the production units, and hope to have more information about a release date prior to Jan 2006.
The Q-Rings are not as effective as Rotor Cranks, as they do not remove the dead spot, however they do allow riders some of the Rotor benefits at a lower cost and less weight, and they can use their current cranksets.
And yes, they are being used in the Tour de France right now, David Canada (Prodir-Saunier Duval) is running them. http://www.cyclingnews.com/...ur051/JD05tdfstg1004
Gary Tingley - RotorCranks.com