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Back tire losing air, but why?

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Back tire losing air, but why?

Old 10-09-10, 11:06 AM
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Back tire losing air, but why?

I'm pretty much brand new to cycling.

I aired up my tires, and noticed that when I put a little pressure on the back tire's valve (Schrader) when it's closed, air comes out of the tire, so when I ride, the air will be pushed out.

What could be the problem?

Do I need a new tire?
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Old 10-09-10, 11:52 AM
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air comes out of the valve? remove and tighten the valve core. you can also try to oil it. a new tube is another option.
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Old 10-09-10, 12:00 PM
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Tube less? If you push on the nd of a shraeder valve it will let air out.
You are not giving much info to go on.
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Old 10-09-10, 01:08 PM
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If you're pushing on the little pin that is what is opening the valve up. That's normal. The air won't leak out when you ride it if that is what you are worried about. If you're pushing the side of the stem around and it leaks then likely your tube has a tear at the base of the valve stem that mostly closes under pressure but opens when pushed around. If so it's not the tire that needs to be replaced but the tube inside the tire.
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Old 10-11-10, 01:31 PM
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I haven't taken the bike anywhere. I felt the back tire again and the air I put in went out. So I'm guessing it needs a new tube.
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Old 10-11-10, 01:53 PM
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I give you enough credit to know that opening the valve by depressing the pin will let air out (duh!!), so I'm guessing that you mean that when you wiggle the valve stem air escapes from the tube, not through the valve itself. That's not rare these days, and means that you have a small tear at the base of the valve or in the reinforced area right near it. Inflation pressure holds it closed, but moving the valve opens it.

You can't ride that way, and need a new tube. After you install it push the valve deep into the tire to ensure that the thick section isn't trapped under the tires bead, then gently pull the valve back out so the base is firmly seated against the rim. This last step is most important with narrow rims because the valve tends to hang up across the narrow gap between the beads, causing the tube to overstretch as it balloons down into the gap formed.
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Old 10-11-10, 02:02 PM
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Riding under inflated, the tire can shift on the rim, the tube can creep inside the tire,
and the valve stem can shear off the connection with the rest of the tube.
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Old 10-11-10, 03:08 PM
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Originally Posted by FBinNY
I give you enough credit to know that opening the valve by depressing the pin will let air out (duh!!), ......
You're right and I really should have apoligised in advance to the OP if that was too basic.

But in my defense his lack of proper terminology in the original post and the fact that we see all to many folks these days that do not have even the most rudimentary of mechanical knowledge makes it less of a shot in the dark than it appears at first.
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Old 10-18-10, 11:31 AM
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I'm female. I'm brand new to cycling. I've got much to learn. It got a new tube.
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Old 10-18-10, 12:43 PM
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Keep plenty of air in the tires/tubes to avoid problems. High pressure road tires need air before each ride, yours maybe not quite so often.
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Old 10-18-10, 01:04 PM
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Originally Posted by nostalgic
I'm female. I'm brand new to cycling. I've got much to learn. It got a new tube.
Nothing wrong with being new and starting out. We were all there at some point. It's actually nice to see someone that wants to analyze and learn to fix things on their own. If my replies above seemed to be condescending or rude in any way then my apoligies. Mostly I was only trying to indicate that your choice of terms implied a total newbie. Nothing more or less.

Hopefully you took advantage of this to change your own tube if you have not done such a thing before. It's always nice to learn in the comfort of your own backyard, garage, shed, parking spot, balcony or even living room if that is what it takes rather in the dark on a rainy night.
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