Relatively cheap, but you have to know your way around wheels (or have a six-pack ready for a buddy that does): http://forums.mtbr.com/showthread.ph...ighlight=boone

Your options for a disc fixed cog are (from cheapest to most expensive): DX cog drilled out, Spicer ti cog, and Boone. For the first two, you can request Gene Spicer drill out the cogs before sending them to you. I use the Boone on a rear Nashbar SS disc hub on my Cross Check (below).

This method will never strip!