Originally Posted by
cyclist2000
normally when you release the pump head from the valve you should hear some air hiss. There is compressed air in the hose that is released when the head is taken off the valve.
Ok, so maybe what is happening is that I hear a hiss when I take it off but no air from the tire is escaping. But then when I put it on again to check the pressure it hisses before I can get it locked into place, and that hiss is air escaping from the tire which is why the pressure has dropped @20 psi?