I recently upgraded my wheels to Zipp 404 and they're great, the problem is I can't pump the tires up with my pumps. I have valve extenders and the valves are open but when I pump I can't force the pump down because it has built up pressure. Fact is I can't get air into the darn tubular. Should I upgrade my pump..again? I can dump CO2s into it but that's just not how I want to do it. Any suggestions would be appreciated, or tips or tricks would be helpful. I've got this super nice wheelset but I can't ride the darn things. I've been told to reglue the wheels and use teflon tape so the air won't escape but that's another high cost.

Thanks.

I'm confused. Is it that with your pump you can't get enough air in? Or, that you get the pressure on your pump up to 120ish and the air still isn't entering the tire?

Have you...

Tightened the exntender with a pliers?
Tried deflating the tires by poking the valve core inside the extender and then tried inflating from ground zero?

I would think this problem would be fixable without reinstalling the tires but I've also heard that plumbers tape is almost a necessity in the world of valve extenders.

The problem is the valves are sticky, and the pump isn't creating enough pressure to open the valve (which is why you tap the valve before you pump it, but you can't do that here because of the valve extender)
Couple of solutions:

1) buy valve extenders that have a core that screws into the tire's core, so you can open and close the valve through the extender.

2) get something long and skinny (I use a bamboo shiskabob stick) and press the valve open through the valve extender before you pump it up.

And teflon tape is a very good idea.

If I tighten the valve extenders and then clip on my pump I can't get the air into the tire. If I loosen the valve extenders some I can pump but the air escapes around the extender and won't enter the tire. I'm going to try and deflate and start from ground zero. Sorry for the confusion...thanks for all your help. Nothing worse than showing up to race thinking you can fill your tires before you rack and not be able to get air into them.

Sometimes presta valves can be sticky. But it could also be that the valve stem is bent and is binding against the inside of the valve extender preventing it from opening and letting in air. The CO2 may be providing a little more lubrication (condensation from the cold) which may be why it works.

Not quite sure how the extenders play into it, but sometimes (about half of the time), the tire is so flat, that the valve sticks open, and you can only pump a small amount at a time.

What I do is when I pump the tire up, I make sure the wheel is rotated so the valve is pointing down. It makes the stem fall down when I tap it, and then air will flow into the totally flat tube normally. Works 60% of the time, every time.

The best option would be to take the tire off and bend the presta head slightly with pliers so it will stay open. Then put teflon tape around it and mount the extender.

Or, remove the tire and buy the Tufo extenders that move the valve core to the tip of the extender.

Either way, the best course of action is to remove the tire and do it right. You don't want to have to mess with the wheels on race day. That will really screw with you to have a flat race wheel 10 minutes before the start.

And teflon tape is like $.99 at the store and glue is $3.00 a tube. $7.00 to fix it right is not bad at all.

Problem solved. Thanks so much for all your help!!

Well what did you do to solve it? and give us the cause and affect for future reference...

Thanks...........