Hey! Not sure if i need a new chain or a new Derailleur. This has just started and i want to find out what it is before i buy that whole new system. I first want to know it its just the chain, which i don't think it is. When i start to pedal, thee entire system works like it should, but my rear wheel is NOT moving. Ive applied a degrease to get rid of all the grease and what nots, but It might have to do with a bearing or something with the cassette. I'm gonna post some video to help explain my situation. Any advise before i fork out more dollar signs would be appreciated.