Notice too that the three chainrings are pretty close in size to each other. I can't tell how many cogs he has in back, certainly no more than five, perhaps four. But they're very widely spaced. So I suspect that what he has is not a half step, but a triple step gearing setup.
--
Peter Jon White
Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
603 478 0900 Phone
603 478 0902 Phax
http://www.PeterWhiteCycles.com