Originally Posted by
bicyclebill1
OK. I am officially an idiot. It tried this morning all methods listed above, both schrader with adapter, and presta without adapter. I could get no air to go in or come out, and I have no idea what my tire pressure is. These are 100 psi max tires, so maybe I am not pushing hard enough on the pump (dont' think so).
After unscrewing the little knob on the valve, did you momentarily depress the knob to let out a bit of air? Presta valves tend to stick in the closed position and if you don't manually open them first and let out a little air the pump pressure is frequently not enough - even if you get it up way over 100 psi. But once you open it momentarily the pump pressure will suffice to do so again.