dug up a post that i had remembered:
Yes. Chances are you're failing with pullups, rows, pulldowns because you cannot pull the weight fully into your chest which requires higher utilization of the forearms and biceps (at the bottom of those movements the ratio of back:bicep/forearm is much greater) due to the in decreased leverages of the back. The easiest example would be the pullup. How often do you see someone do a pullup and them only get about half way up? The lats are much more engaged at the bottom of the pullup - and stronger than the biceps/forearm as well as being in a biomechanically advantageous position - which allows them to get to that half way position and it's the biceps/forearms that fail to help get them to the completion of the rep.
Very very rarely is the back going to tire before biceps unless pre-fatiguing methods or other various "special" methods are used to force it to do that. The back is simply a much larger muscle group and has a much higher work capacity.
really wish that dude LM16 didn't stop posting, he always had something good to say and was pretty accomplished as well. this was in the context of someone doing pullups for their biceps, but it seems to be that pre-fatiguing biceps would just cut down your total reps; based on what LM16 posted it makes sense that flame's friend did well with weighted pullups for his lats.
also, obligatory ironaddicts refence:
ROM looks like it would murder your lats