Simple question really, but you know the internet, google a simple question and you get so many random answers its hard to tell what is relevant. So I come back to the horse's mouth (as it were, strange idiom.)
I rebuilt my whole drive train about this time last year, and a long learning process it was. This is the first bike, road or mountain, I have had that wasn't knackered once the drive was gone and worth rebuilding. Everything else was just ridden into the ground or sold or stolen (once!) Since then I have ridden more than ever before and covered 5386km/3347miles.
Recently I have hear a little clicking/clacking/cracking rhythmic knocking noise coming from down below, this only happens when I am in a high gear and meet a slight incline; this effectively puts me in too high a gear and putting more pressure on the pedals. If I shift down and spin a bit faster the noise stops.
The rear mech/cranks/cassette replaced Mar 2012 all still feel sharp and new so I suspect the chain. I imagine changing the chain can prelong the life of the other parts. So how far/how often do you change your chain?