'Presta' Pain in my a$$

[smufguy]

Okay, I know this many sound like a very dumb question, but bear with me please.

I run presta valved tubes on my bike. As of late, i switched to specialized think walled tubes. The problem I am having is the stupid unscrew-able stopper on the top keeps braking. First time I broke it, it was my fault. The pump was not inserted properly and the wiggle broke the tip. Okay fine. Yesterday I broke two, and thats with being very careful.

Can someone please tell me (technical advice please) what the heck I am doing wrong here. Tubes are not expensive, but I dont want to piss $6.00 every time because I cant use the damn valve stem properly.

 

[RNG1]

That's weird, I would guess it has more to do with the pump you are using as a guess.

 

[smufguy]

I have used my Topeak hand pump and the Bell floor pump. Bell sucks for sure, but their adapter for presta valves are just gooky.

Question, when I air my tires, I normally unscrew the top part of the valve and then insert my pump over it and pump it up. Is it the proper way to do it?

I am also tending to believe that it might be the stupid specialized tubes as well. I have the one in my front, which I got from Efingers (some brand i cant remeber, with an orange cap) and its fine.

 

[RNG1]

Hand pump could be an issue if you are not stabilizing the valve with your fingers by the support of a couple of spokes. It has never happened to me but I guess if it is rocking back and forth it could break. To answer your question, yes you do need to "unscrew" the head of the valve. I bet if you got a good floor pump that latches on and you were not moving it around a lot like with a hand pump you would not have a problem.

 

[FFT]

I know exactly what your talking about. Dont unscrew the cap all the way. It only needs about a half turn to properly inflate. A full turn and a half and it's bound to break. I also use an adapter to avoid trailside presta carnage; the adapter protects the "nipple"from breaking. I am impatient and have snapped more than a handful of those buggers.

 

[smufguy]

Could you be kind enough to steer me to those 'adapters' you mentioned please?

 

[FFT]

http://www.treefortbikes.com/542_333222333520__Brass-Presta-Adapter.html

I leave the valve closed with the adapter srewed on. It will make sense once you get one to play with.

 

[creeker_1]

Ya beat me to it, here is another

http://jensonusa.com/search/?s=presta+valve+adapter

I carry one for trailside use as well. Other thing I was wondering is, are the pumps set up to be run presta or shrader with the little needle compressor in the opening?

 

[mtn_goat]

If the pump has the little needle in the opening, it is set for sChrAdeR, just like a CAR valve stem. The needle in the pump opening pushes down the spring loaded pin in the valve, which then opens the valve stem to let air into the tire. The spring in the valve closes the valve, not air pressure.

If the pump is set with no needel in the opening, then it is Presta. These use air pressure to push open the valve, if the pressure is higher on the pump side of the valve, then the air will enter the tire, when the air pressure is higher in the tire, it pushes the valve closed.

 

[smufguy]

Thanks for the links to the adapters. Its the adapter that broke my presta valve stem. The floor pump that I got came with an adapter that screws on top of the presta valve to be inflated by the shrader pump head. What would be cool if the adapter would screw at least half way to the stem of the valve so it has less chance of rocking the valve that caused mine to snap.

http://www.ehow.com/how_4779541_inflate-bicycle-tire-presta-valve.html <<< says the same thing we know

 

[graveyardman67]

Minor, but also helpful. Sometimes I find the valve will stick even after unthreaded a bit. As a matter of habbit I always push it down with my finger before inflating to make sure the valve unseats.