I am currently running a BMX style freewheel on the stock rear wheel. I am interested in going fixed, but I don't want to spend a lot of money on a new track frame. What kind of options do I have for threading a cog onto the stock hub? I have seen products like this \/\/\/
Is this a viable option? Or am I really off base here. I know I would need to space it out to have a good chain line.