Originally Posted by
zvez
ok newbie here, I'm guessing you really don't need the black cap because the valve cap nut is tightened? Guess I better go out to the garage and ditch em.
The way Presta valves are made, they do not allow any sort of dirt or water entry when the valve sealing nut on the end is closed. A cap is not necessary to seal out the elements. This is not the case on Schrader valves with removable valve core. Dirt and moisture can get inside those and cause problems, making the valve cap a necessity.