I would (and do) go with long cage on both my bikes. Triple chain ring systems usually require long cage. Medium or short cage with today's 11-34 rear cassette and a 22-32-44 front rings isn't wise unless you are very disciplined and never go anywhere near the big-big or small-small front-rear combo. Its all about the maximum chain wrap capacity of the derailleur. A medium or short cage derailleur just does not have enough chain wrap to allow for both situations so you have to compromise and either make the chain short enough to not go slack in the small-small combo but then it isn't long enough to handle big-big and you risk destroying your derailleur, or leave it long enough for the big-big and expect that you will drop the chain when you to near the small-small combo.wilcox510 said:Just bought an ETSX, and I'm planning to put SRAM x9 shifters and rear derailleur on. Do I need the long cage or the medium cage or what?