A friend is looking at setting up a single speed on the cheap.
I took the six speed cassette of the wheel and it looks like it has a freehub design but one I haven't seen before. The largest three sprockets slide on to a larger diameter portion of th freehub and the next smaller two slide onto a smaller diameter portion of the freehub. The smallest (13t) then threads on to fix everything in place. Is is possible to convert this to a single speed and acheive a straight chainline?