I struggled with the pipe for many years, but after a little internts digging and some trial and error I have perfected my technique. I wrote a little write up here: http://www.acmebicycleco.com/2012/09/24/how-to-properly-use-a-crack-pipe-aka-disk-wheel-inflation-adapter/
I thought others might be interested in learning proper pipe technique.
Sorry the photos are poor quality, I took them with an iphone early in the morning.
content copied below:
Behold the crack pipe, a small and poorly designed device that you are supposed to use to inflate your tires on your fancy disc wheel. For all the money that goes into developing the wheels it would be nice if the adapter that you NEED to use to pump the tire was designed a bit better. I have spent many race mornings cursing at my crack pipe for flying off the valve stem when trying to inflate and making race morning that much MORE hectic. Finally, I took it upon myself to learn how to use the thing properly and I can actually use this little marvel without using three hands or recruiting help from the competition.
In order to use anything properly, it is important to understand how it works. A crack pipe is made up of three parts, an “L” shaped body, a screw on cap and a rubber grommet. The grommet is located between the cap and the body and the orifice is what receives and seals against the valve stem. What many people don’t realize is that crack pipes have a tightening function by which they grip the valve stem just like an ordinary inflator head. Most people just shove the thing on the valve and try to pump up the tire and then get frustrated when it won’t stay on during pumping. With the grommet between the screw on cap and the body, as the cap is tightened the grommet is squished and the orifice seals around the valve stem and holds quite tightly.
Here is a crack pipe disassembled, note the three pieces.
To get started with a crack pipe, open up the valve on the tire.
Place the crack pipe on the valve and push it on as far as it will go.
While pushing the assembly onto the valve, tighten the cap on the crack pipe, it will get harder to turn as you go. Tighten it as much as you can by hand. (Tip – apply a little great to the cap threads to allow you to tighten a bit more)
Once you have tightened the cap to the body as much as you can give the assembly a little pull to make sure it is gripping the valve stem tight. If so, go ahead and attach your pump to the barbed tube that extends from the body.
Pump the tire up to your desired pressure, the crack pipe should hold the valve tight.
Once you have finished pumping, remove the pump head and carefully unscrew the crack pipe cap from the housing. Slide the housing and the cap off the valve stem piece by piece. The reason to do this is because space is often tight in the disc wheel cut outs and by taking the crack pipe off piece by piece, there is less of a chance of accidentally disturbing the valve and letting air out of the tire.
Tighten up the valve, put your crack pipe back together and you are ready to race.