I have the worst luck lately. Flat tire after flat tire. I'm getting good at changing them so I guess that's a plus. So, I'm out in the desert this morning busting down this beautiful sand wash with some rocks in it and all of a sudden, I notice my rear tire is flat. Great. Checked for slices and found none so I figured I had pinched it. I get the tire off and what do I find? The valve stem had completely separated from the tube! I have never seen this happen and am baffled as to why. This was a brand new tube in a brand new tire. So, I'm asking my fellow TTer's to check out the photo and give me an explanation! Brand new D606 rear tire. Brand new Fly 4mm HD tube running 14psi. Both rim locks were tight. I always leave one nut on the inside of the rim and one on the outside (on the valve stem) to keep from pulling the stem out of the tube. Didn't work too well this time, though.