on sheldon brown's website it stated that it was possible to convert a freewheel to fixed gear for singlespeeding. i did not quite understand when he explained how to do it. i was wondering if someone could explain it to me in simpler terms or with pictures/diagrams or whatever? i hope to convert an old 7sp freewheel into a singlespeed fixed gear using a singlespeed freewheel and the conversion method. TIA.