Bicycle Mechanics - Silca #40.0 Air Puimp Head Question

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Altair 4
04-07-11, 09:43 AM
I have an air pump that I use for my Schrader equipped bikes. However, the old head would blow off the tire / tube stem while reaching higher inflation rates, say above 60 PSI. The gripping mechanism is worn out.

So I check around the web and I see a Silca replacement air chuck that says it works on both Presta and Schrader tubes (Silca's website says it works on both). I bought and installed it. However, it won't inflate a Schrader tire. There is no center pin in the head to depress and open the Schrader valve in the tube stem. There are no printed instructions at all with this chuck.

I wrote the vendor and got this reply:

Please do not take this the wrong way because we help customers with varied bike knowledge, but are you sure it is adapted properly. Are the mechanics at you local bike shop nice enough to take a look at it for you?

I hate to drive 20 miles to my LBS to see what the deal is. I know the rubber insert had to be reversed to fit and clamp onto the Schrader stem. What other adaption is necessary to use this chuck? I unscrewed the locking clamp mechanism from the part that inserts into the rubber air hose. Interestingly, the insert looks like it has the center pin. But it would have to be screwed onto the tube stem to work. I don't see how that would be useful at all for several reasons - I can't unscrew it fast enough to not lose a massive amount of air pressure. And it doesn't spin or swivel. I'd have to turn the entire air hose to use it in this manner.

Tell me what I'm missing or the thing goes back! For $27, I can just buy a new pump.

http://img.photobucket.com/albums/v220/Altair4/silca400.jpg


cyclist2000
04-07-11, 02:53 PM
I think that the section with the "pin in here" is designed to be screwed on to the schrader stem. Colorado cyclist sells these and it seems that that is how they describe it. I never understood how this pump heads work with schrader, I have a very old silica pump with the brass head and it seems to just screw onto the schrader head, never worked very well for me, but I didn't have any bikes with schrader when I purchased the pump.

fietsbob
04-07-11, 04:09 PM
Yea the screw on to the schrader stem part is the one to be directly connected to the hose.
the Presta thumb lock is screwed in place of the Schrader stem.

not as convenient as a Schrader thumb-lock head. If you use the s/v tubes a lot..


Altair 4
04-07-11, 06:58 PM
Yea the screw on to the schrader stem part is the one to be directly connected to the hose.
the Presta thumb lock is screwed in place of the Schrader stem.

not as convenient as a Schrader thumb-lock head. If you use the s/v tubes a lot..

You are right! I wished I had known that before I ordered it. Any recommendations for a Schrader thumb lock head? I have a small compressor pump that has worked nicely inflating my bicycle tires. Low volume, yet high pressure, but the original head is worn out.

davidad
04-08-11, 02:20 PM
Go to the auto parts place and get one with a hose clamp. http://www.google.com/products/catalog?rlz=1T4RNWE_enUS308US308&q=Ball+chuck&um=1&ie=UTF-8&cid=6888920018838424998&sa=X&ei=AW6fTaG8LcPB0QGFgOX7BA&ved=0CCkQ8wIwAw#

Altair 4
04-08-11, 02:51 PM
I think I'll stop by my local auto parts store and see what they have. Ideally, I'd like one with a thumb lock, but that's starting to look like maybe that's just not available.

cyclist2000
04-09-11, 09:27 PM
I looked at mine tonight and the schrader end works quite well. Just like the lezyne pumps.

Bianchigirll
04-09-11, 10:14 PM
Ideally you need two pumps. one for schrader and one for presta