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Thread: Tire Woes

  1. #1
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    Tire Woes

    So the other day near the end of my ride, I noticed that my rear tire had very low pressure (not flat, but maybe <20 psi). Because I was near the end, I decided to just pump it up with my hand pump. Of course, by the time I got back it was pretty low again, but it held some air. My rear tire was in need of replacement, so I decided to put on an old tire (very unworn, but not brand new. Of course, I forgot to replace the tube at first, so it lost pressure as well. And when I did replace the tube, all I had was my hand pump, so I probably only got it to 60 or 80 psi. But it held the pressure all night and through my next ride. After that ride, I finally had access to a floor pump, so I pumped it up to the usual 100-110 and left it overnight. I came back this morning, and the tire was basically flat. The real reason this seems odd to me is that it lasted 15 hours at a bit lower psi, but once I fill it to 110, it loses all its air in about 12 hours. I'm wondering if anyone has any suggestions as to what might be the problem, or how I might go about fixing this?

    Thank you!

    Joe

  2. #2
    Bianchi Goddess Bianchigirll's Avatar
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    do you have presta or schrader valves? either way it could be a sticky valve.
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    I doubt it's a valve probem - you'd still lose some are at 60 lbs. We can guess a lot, but there's no point in doing so. Remove the tube but keep it in the same orientation to the wheel, and dunk it in water to see if you can locate the leak. If so lay it back on the wheel and inspect the tire or rim at that point (depending on just where the leak is). If you can't find the leak then inspect the rim and the entire tire inside and out, looking and feeling (carefully!) for any possible causes. Patch or replace the tube and go.

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    Senior Member gyozadude's Avatar
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    The higher pressure could have caused the tube to become pinched and cut by its own pressure. This is true if the rim-strip that protects the tube from the rim eyelet holes and spoke heads is compromised. You may want to check that out as well.
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    Just a quick update: Took the tube out, and lo and behold, I couldn't find any sign of a pinch or puncture. I pumped it up pretty high too, so I'm pretty sure there's nothing. This makes me think it could be the valve. I did a tire and rim check, even reapplied the rim tape just in case. I also took out my kevlar strip just in case that was doing something.

    So I pumped it up to 100 and am going to let it sit for a few hours and check to see what's up.

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    Alright, another update. After less than 4 hours, the tire was pretty much completely flat. And again, this was with a different tube. And on the previous tube, still no hole has been found anywhere. I really have no idea what could possibly be going on here...

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    Have you tried water boarding the tube to force it to reveal the leak?

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    Slow leak means you have a thorn or piece of wire in your tire.

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    I wish this was the issue, but I checked the tire very thoroughly, and found nothing.

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    I've had similar experience, and finally tracked it down to a bad valve/tube connection. The slightest change in the valves position either had the area self-seal or leak. Of course it tended to act up in the rain, but hold air overnight, so I'd be suckered into leaving it alone.

    Tubes are cheap. Replace it and move on. While it's out, pump up the tube to half again it's empty size and flex the valve stem to see if you find an area where the tube isn't attached poorly.
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    Quote Originally Posted by joeturner View Post
    I wish this was the issue, but I checked the tire very thoroughly, and found nothing.
    Checking the tire will be a loosing proposition until you know where the tube is puncturing. It might not be the tire.

    First, mark the tire where the valve is so you will have a reference on the tire when you find where the tube is leaking. N.B. this step can be eliminated, if you lined up the valve with the tire label when you mounted the tire on the rim.

    Second, take the tube out of the tire and inflate it to many times its normal size. The more the tube expands the larger the leak hole will become and the easier it will be to spot.

    Third, take a bucket of water and completely immerse portions of the tube (including the valve) completely in the water (water boarding). Look for bubbles even ones that appear once every few seconds. Trace their source. The bubbles will lead you to the hole in the tube. Don't stop after a single hole is found. Go all the way around the tube to discover more than one leak. Also, when the valve is immersed, I'll twist it back and forth to check for holes at the valve base.

    I'll usually mark the hole by placing a round toothpick in it as each one is found. This enlarges the hole so there's no loosing it. I'll usually patch the tube at this point. This gives me a good tube and permanently marks where the puncture was.

    Fourth, now go back with the tube partially inflated to match the tire size and line the valve up with the tire. Where the patch(es) are should be where to look for the flat source in the tire. I've only referenced the distance from the valve hole with the tire mark no the tube's orientation. I'll flip the direction of the tube to check the tire in an equal distance from the valve but in the opposite direction.

    If the puncture was on the tread side, I'll look for evidence of some small sliver stuck in the tread. I'll look for marks on the inside of the tire where that sliver might have penetrated.

    If the puncture was on the side, I'll look for a hole in the tire sidewall. This is usually a much faster leak. Sidewall holes are usually caused by brake pad rubbing.

    If the puncture was on the inside, I'll look for something sharp inside the rim.

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    Did this with both tubes, and once I got the pressure really high, I could see some bubbles coming out from a previous patch–it both cases. I must be terrible at patching tubes to have this happen with two tubes in a row. And this would make sense for high pressure => flat.

    Also, as a side note, I would never recommend Vredestein tires to anyone simply because of how amazingly hard they are to get on and off. Spent at least 15 mins getting it off each time.

  13. #13
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    Quote Originally Posted by joeturner View Post
    Did this with both tubes, and once I got the pressure really high, I could see some bubbles coming out from a previous patch–it both cases. I must be terrible at patching tubes to have this happen with two tubes in a row. And this would make sense for high pressure => flat.

    Also, as a side note, I would never recommend Vredestein tires to anyone simply because of how amazingly hard they are to get on and off. Spent at least 15 mins getting it off each time.
    Glad you solved your problem, but don't worry it's not you: inner tube patching is much less reliable than the mechanics of this forum would have you believe...there are so many ways for it to go wrong (both within and outside of your control).

    As to getting tires on and off, I struggled for years with a bike that was hell to get tires on and off. I tried everything and here's what I found were the most effective solutions for easier tire removal (in order of effectiveness):
    1. Use narrower tubes because the narrower the tube the more space there is for the tire beads to get in the rim well.
    2. Use wider rims.
    3. Use softer tires and/or tires with kevlar beads.
    4. Use better tools like the Kool Stop Bead Jack and wider tire levers like the Park Tool TL-4. However, if you do steps 1, 2, and 3 then you won't need tools at all.
    5. Don't get flats and you won't have to take the tire off.
    Notice that the tire itself is pretty low on the list.

    Hope that helps someone.
    Last edited by chucky; 05-22-12 at 08:36 PM.
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