valve stem extenders ?
461
Member
1262 days
rbreddin75 posted 3 years ago.
when you added the valve stem extensions, did you open the top of the presta valve? or did you leave it closed...
if you left it closed, the 105psi is just measuring the pressure you are building up in the extension itself, which explains why it goes to 0 when you pull pull the pump off...
make sure that the presta valves are open, otherwise all you are doing is pressurizing the extension
[URL=http://rbreddin75.trifuel.net/][COLOR=DeepSkyBlue]PARADIGM : Triathlon
As Iron sharpens Iron, so one man sharpens another. proverbs 27:17
[url=http://www.northatlantamultisport.org]
As Iron sharpens Iron, so one man sharpens another. proverbs 27:17
[url=http://www.northatlantamultisport.org]
31
Member
1257 days
Action posted 3 years ago.
for sure they are open, otherwise I would still have flat tires !, the pumping works fine, the tires got inflated, the question is why does the needle go back to 0 after the max. point of the down stroke on the plunger ?
163
Member
1570 days
Kevo posted 3 years ago.
Sounds like it could be the guage on your pump. Try another pump if you have access to one and see if that makes a difference.
"You can quit and they don't care, but you will always know."
97
Member
1321 days
xcdave posted 3 years ago.
I have the same problem.
I talked to someone in a bike shop about this very problem last week. He said to look at where the gauge stops right before it falls to zero, that's the pressure in your tire.
There is such a thing as an extender with an O ring that did a better job of sealing than the plumbers tape - I used to have one many years ago, and that seemed to solve my problem.. I can't find any around now though.
I did buy some Vredestein tubes that have super long stems (80 mm i believe). I think they're going to work with my HEDs. Depending on how deep your rims are, you may want to check something like that out instead.
31
Member
1257 days
Action posted 3 years ago.
xcdave, thanks for the info, it appears these things are very finiky, last night the gauge held on the rear but not the front, i think that it has to do with getting a precise fit from the air hose clamp on to the extender, otherwise, once the down stroke is complete the stem from the tube pops back up and the pressure thru the extender to the pump is nil, no pressure loss in the tire, just in the extender to the clamp.
I have these valve stem extenders on my zipps, used the plumbers tape for a good seal, yet when I pump the tires the needle on the gauge goes to say 100psi then as you pull the plunger up the needle goes down to 0, then on the down stroke the needle goes to say 105psi then to 0, hope you get the picture. Its not the pump, works fine on reg. wheels. Is this normal ? Do I need to tighten the extenders more? and Can I assume that the max. point the needle reaches on the gague before going back to zero is the air pressure in the tires?