David Millar (Garmin) riding some sort of Biopace type chainring?
 

I just noticed that David Millar was riding some sort of Biopace type chainring while watching a recording of yesterday's stage. Anyone familiar with what he's using and why?

I did some googling and found:

http://tbtaward.files.wordpress.com/...chain-ring.jpg
Source: http://tbtaward.wordpress.com/2010/0...ly-chain-ring/

http://www.osymetric.com/

My understanding is that its supposed to help the rider pedal quicker over the top and bottom of the revolution. Something like that. I thought it was primarily used on TT bikes.

That looks quite a bit more hardcore than biopace, but then again I didn't find biopace to be very noticeable.

Similar to what's on the Cervelo Test Team bikes, they use 'Q-Rings'

http://www.rotorbike.com/nueva/ingles/road_qrings_130bcd.htm

http://www.cervelo.com/en_us/testteam/testteam-bikes/