Combination Presta-Shraeder Pump?
10-06-15, 08:53 AM
#1
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Combination Presta-Schrader Pump?
How does the pump decide which valve the air comes through? My presta one won't work.
It did at one time, it only comes through the scharger hole. I've put the presta stem in many times, no different results. And I can't find my schradoer adaptor. Thank you.
It did at one time, it only comes through the scharger hole. I've put the presta stem in many times, no different results. And I can't find my schradoer adaptor. Thank you.
Last edited by turtletop; 10-06-15 at 08:56 AM. Reason: Spelling
10-06-15, 03:17 PM
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I assume you don't mean one where you disassemble the head and reverse the internals. If I'm wrong there, I just answered the question.
The others use an internal slid valve that closes the side with zero back pressure, diverting the air flow to the one with the valve. I hate his design because it's so sensitive and the valve gets sticky over time letting all the air go out the unused port. This is especially common if the valve is used with the same type of tire valve allowing the diverter to get stuck in place.
Over the years, I've had success freeing them by banging against the ground, or spitting in them to lubricate the diverter. Or you can try a good wash is detergent and water along with some manhandling. In some cases I've had to take the assembly apart, work the diverter until it moves freely, grease and reassemble.
So far, I almost always get them working OK without too much effort, but IMO, it's plenty of wasted effort for the marginal convenience this design affords.
The others use an internal slid valve that closes the side with zero back pressure, diverting the air flow to the one with the valve. I hate his design because it's so sensitive and the valve gets sticky over time letting all the air go out the unused port. This is especially common if the valve is used with the same type of tire valve allowing the diverter to get stuck in place.
Over the years, I've had success freeing them by banging against the ground, or spitting in them to lubricate the diverter. Or you can try a good wash is detergent and water along with some manhandling. In some cases I've had to take the assembly apart, work the diverter until it moves freely, grease and reassemble.
So far, I almost always get them working OK without too much effort, but IMO, it's plenty of wasted effort for the marginal convenience this design affords.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
10-06-15, 03:32 PM
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As far as I can figure, the pump head isn't meant to come apart. The rubber air hose comes off, but that doesn't affect anything. Maybe I could swirl it in water with dish detergent.
Bought two schrader adaptors at bike store for $5.60something. I'll go right back!
Bought two schrader adaptors at bike store for $5.60something. I'll go right back!
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