I used the plastic zip ties to attach mine to the bottom of my downtube. It just clears the front tire and goes almost all the way to the bottom bracket. I have my pumps like this on both my bikes because it is the only place where it will fit on my small frames, not interfere with the water bottles, and doesn't get bumped by my legs.

This is an old photo (not my current bike!), but you can see the pump in the same place on this bike as well...