I'm quite new to bikes. I have a Schrader valve bike with deflated wheels. When I try to pump it up. I take off the protective cap, then there is a valve secured down by a nut (there is another nut securing it to the actual wheel) I then put the pump onto the bit of valve poking up and lock it in. I can then pump it completely with about 5 pushes of the pump. Once it is complete I unlock the bike pump off of the valve, at that moment all the air rushes out immediately (10 seconds) even if I put the protective cap on. What does this mean??
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Very strange. The protective cap has nothing to do with air retention. It is to protect the valve from mud. Do both tires behave in this way? Are you sure it is a Schrader?– VoracCommented May 23, 2013 at 9:10
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1Do you mean presta? Schraders have either 1 or 0 nuts.– alexCommented May 23, 2013 at 9:48
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A Schrader has no nut securing the valve. It does have a "valve core" which can be unscrewed for replacement or to let the air out of the tire, but you should leave that alone. If instead you mean Presta, there are several good descriptions here on how to inflate one. (And I doubt that any normal bike tire can be properly inflated with 5 pushes of a floor pump.)– Daniel R HicksCommented May 23, 2013 at 10:54
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This link shows the Schrader and Presta valves.– Daniel R HicksCommented May 23, 2013 at 10:58
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3Five pumps sounds suspiciously like "I screwed a Presta valve the wrong way, so none of my air is actually going in the tyre. After five pumps I can't get any more in, so I take the pump off, and the air comes out". But you would have thought he would notice the tyre was still flat in that case. Even a small child's bike tyre takes more than five pumps to actually inflate from flat to normal pressure though.– armbCommented May 23, 2013 at 15:02
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1 Answer
From these three, which one you have?
Case ①:
Schrader valve
Check if the inner part (valve) is properly installed (tight enough). If is and still loose air — you need to change the valve or the inner tube, the problem is with one of them.
Case ②:
Presta valve
You need to unlock the valve before pumping, or you will pump air only into you pumps' hose. After pumping don't forget to lock the valve back.
Case ③:
Woods (Dunlop) valve
Very old system. Check inner parts (steel needle and rubber tube) for damages, rubber tube can degrade flexibility with years → air loss.
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Thanks for the replies. Sorry about the description it is case 3 the Dunlop valve. Thanks– jameeCommented May 24, 2013 at 5:16