I was supposed to go on a ride tonight. We made it about a mile before I got a flat. I patched the pinch flat I had gotten from the rim-strip being pushed over. The tube popped on a spoke. After pumping up to about 40psi, it starts leaking. I think it's the pump. I try again, no good. So I pull the wheel off, take off the tube and replace it with a new one. I put a dollar bill in the rim to hopefully avoid the pinch-flat problem. Start pumping. Get to the same place and I hear the rush of air again. I pull the pump off, pick up the wheel and I can still hear it rushing out. Something is not right. I pull off the tire. The rim strip had been shoved out near the valve hole. Pressure was forcing the stem over a sharp edge and cutting the stem halfway off the tube. OH. At least it was inspirational.

This shows the spherical bearing and pinch bolt.