Hi, I'm new to this whole bike moddin'. Coming from moddin' cars I thought this was gonna be easy- I was wrong. I got a pair of China Schwinn repops built in '06. I wanna add a seven speed(or more) to one. I'm completly lost on this whole Freewheel/freehub thing. I'll have no problem stretching the frame wider or welding brackets for the derailer. But I don't know what hub to buy. I know I need a 28hole? so I could keep my original 20" rim. I know I don't really want an internal cause I like the look of the derailer hanging down there. I have a Shimano 7spd derailer from a Mongoose 21spd I intend to use but taking the hub from that bike has provin to difficult for me(I've never worked on a bike before). Anyone know what I should buy as far as the rear hub,freehub? and sprockets? Do they have to be from the same company? I can't get the hub on the Mongoose away from the sprokets! Is any off that stuff of any value to me for my task? Help! Please!