I’m setting up my stuff for a race tomorrow and my front Blackwell 100 tubular won’t take air. It has a zipp valve extender (the black one that screw over the core in the tube but doesn’t replace it) and when I try to pump it the needle on the gauge just pegs to max but it doesn’t air up the tire. I unscrewed the extender several times and reattached it but to no avail. Hopefully one of you out there has the easy cure before i throw my wheel across the garage.
Sorry, I use clinchers, but the same thing happens to me when I first begin to pump. I jiggle the pump valve when it’s seated on the stem until I hear a little click and the pump gauge drops down to a true reading, I can fill it up from there.
Did you try releasing a little air first using an unfolded paperclip inserted into valve extender? That’s helped me in such situations.
yeah I can usually fix it by shaking the head of the pump on the tire valve but this one won’t budge. I think part of the issue is I haven’t used the wheel in months and it has zero air in it.
I have heard of the valve core threading itself closed from road vibrations, that’s why I either pinch the threading or put plumbers tape around it to prevent this. Or it could be another issue that requires you to break the seal of the valve core. Just stick something skinny in the extender and tap the valve core and try to get air to release from it.
That’s the problem it doesn’t have any air in it to release. I stuck a brake cable down it to make sure the valve was down (open)
Best guess is that the valve stem is screwed shut (probably when attaching the extender). The best way to fix this is to use the extender to unscrew the valve my pressing it against the side of the value and turning it in the “unscrewing” direction. Then put the extender back on being very careful to keep it centered so as not to rescrew the valve. Since there’s no pressure in the tire, your problem can’t be stiction in an open valve.