Yo /fit/I recently purchased a doorway pull up bar and have begun using it on a daily basis. Pic related, it is the exact model I bought. As you can see there are several grip positions possible, so you can assume that I can do most any pull up/chin up possible.What is the best pullup/chinup to build biceps? I can do an overhand or underhand grip, and that grip can range from a width greater than my shoulders to touching fists. I can also use the extending bars you can see in the image to do pullups running parallel to my arms instead of the normal perpendicular.
If you weren't an idiot, you would do each kind of pull-up and see which hurt your biceps the most, but the reverse grip pull-up should be the best.
Pullup - overhand gripChinup - underhand gripchinups with your hands together will hit your gunz the most.