I have just replaced the crankset on my Mongoose ATB and have put the old one on the Hardrock. The problem is with the Alivio that I have put on the Hardrock. I am thinking that the derailleur that is on the the bike won't work with the crankset. The old crankset is an off-brand that has a big chainring with 48 teeth and the Alivio is 42t.
So, my question is this...
Do different cranksets require different derailleurs? And what is the difference between a top and bottom pull derailleur? I ask this because I do not know which one I would order if it turns out I need to get a new derailleur.