I have wasted nearly 45 minutes trying to put air in a new tube I just put on my Fargo. I got the first 5 or so pumps in just fine (before I re-seated the tire). Now nothing will go in. My floor pump just builds up air in the tube and it doesn't go into the tire. My hand pump will pump air that goes somewhere (the air isn't building up IN the pump) and the tire appears to move a little with each stroke...but it isn't inflating. Now, this isn't a brand-new tube, but it was on my Niner for about a week before I had the shop take the tubes out and switch that bike back to tubeless. It pumped up fine before. And the floor pump will pump air just fine into the other tire on the Fargo.

I really, really do not want to have to take the tire off and put yet another tube in, but is the valve on this tube bad? And how on earth did it just spontaneously go bad, if that's the case?