Quote Originally Posted by zia View Post
Is there supposed to be complete silence when you're not pumping, or is some hissing to be expected?

Hisssssssssssssss....
I don't recall any hissing when the pump was demonstrated to me at the shop or when I tried it myself at the shop. I just tried my pump again using suggestions on this thread. I looked at wedsites with videos demonstrating pumps. Same old hissing sound. My pump is a JoeBlow Sport II. Do any of you have this pump? If so, do you have trouble using it. As I said before I used perfectly at the bike shop but I've had trouble since then. It's driving my crazy!!!!