1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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  1. #1
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    Why are my spare tubes flat?

    Ive only been mtb for about 7 months and have had two flats. Both times the spare tube I carry also had a leak. One was on my 29er. The other on my 26er.

    Any thoughts about what typically would cause this?

  2. #2
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    Quote Originally Posted by goodmojo View Post
    Any thoughts about what typically would cause this?
    Yeah, not fixing what made your tire go flat in the first place would be the first cause of your spare being flat.

    As precaution, I always carry my spare tubes wrapped up in a rag. I've seen people keep them in plastic bags to good effect too. But every time you get a flat, you need to find what made it go flat and fix it before you even unwrap that new tube.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  3. #3
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    I do a few things to make sure my tubes say in good shape.

    1) I keep the tube in my camelbak rather than a seat bag. The seat bag see all the vibrations and bouncing from the trails. My camelbak see much less. I have had tools rub into tube wearing in a hole.

    2) I wrap the tube in rag. I keep the tube in it original wrap from the box (I ditch the box) and put rag around the tube. I also keep few spare chain links in the rag, but with it all wrapped up I minimize rubbing. I put this into a regular sandwich style ziploc bag.

    3) I always carry a self sticking patch kit just in case.

    4) I use patched tubes all the time, but never as trail spare tube. I worry about the folded tube damaging a patch and I don't want to have my spare leak when I need it most. At home it is no big deal. And I also change out the bad tube when I get home to always keep.

    5) This is key. I run my hand in the tire to look for any thorns that could case a fresh tube to leak. It takes a bit of time, but is a key step.
    Joe
    2003 KHS Alite 4000 26" Hardtail - XC, All mountain, blah blah blah.. I just ride.

  4. #4
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    I use 26x2.1-2.5 tubes for all 29x 2.25 tires without incident. Those things can really expand. This may allow fewer pinch flats, because I haven't had any at 15-20psi front and 20-25 rear on Schwalbes on ArchEXs.

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    Quote Originally Posted by eb1888 View Post
    I use 26x2.1-2.5 tubes for all 29x 2.25 tires without incident. Those things can really expand. This may allow fewer pinch flats, because I haven't had any at 15-20psi front and 20-25 rear on Schwalbes on ArchEXs.
    Correlation does not imply causation.

    Using a smaller tube in a tire causes the rubber to thin out which makes it more susceptible to pinch flats, abrasion, or punctures. Consider yourself lucky. Yes, tubes are very elastic and this can certainly get you out of a pinch in the woods but I wouldn't run it long term. Now running a 1.95 tube in a 2.3 tire, that might be a lot more acceptable.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  6. #6
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    Quote Originally Posted by zebrahum View Post
    Yeah, not fixing what made your tire go flat in the first place would be the first cause of your spare being flat.

    As precaution, I always carry my spare tubes wrapped up in a rag. I've seen people keep them in plastic bags to good effect too. But every time you get a flat, you need to find what made it go flat and fix it before you even unwrap that new tube.
    On the 29er it was a burp, on the 26er it was a pinch flat (I think). In both cases I couldnt pressure up the tube at all. I think the holes were made before I put the tire in.

    But this is a good point, Ill check the tire.

  7. #7
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    Quote Originally Posted by zebrahum View Post
    Yeah, not fixing what made your tire go flat in the first place
    ...
    ... or, as Park Tool puts it:

    "It is important to always inspect the tire as well as the inner tube. The cause of the flat, such as a nail or piece of glass may still be embedded in the tire or tread. Inspect both the outside of the rubber tread and the inside of the casing."

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    "it IS possible that you are faster or slower than anybody else who is having at least as much if not more or less fun"

  8. #8
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    Quote Originally Posted by goodmojo View Post
    On the 29er it was a burp, on the 26er it was a pinch flat (I think). In both cases I couldnt pressure up the tube at all. I think the holes were made before I put the tire in.

    But this is a good point, Ill check the tire.
    I'm going to keep pressing this issue to make a point...

    Did you inflate the tube after you took it out to confirm a pinch flat? After the tubes you put in didn't inflate properly, did you take them out, inflate them off the bike, and inspect where/why they were flat? You can't ever fix a problem if you don't determine the cause first. Keep at it and hopefully you can pinpoint (pun intended) where these problems are coming from so you can prevent them in the future.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  9. #9
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    Check the rim for burrs too.

    "it IS possible that you are faster or slower than anybody else who is having at least as much if not more or less fun"

  10. #10
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    Carry a cotton ball in your kit. You can run the cotton around the inside of the tire and find thorns/splinters/glass that will snag the cotton. I have found objects that I could not feel with my bare fingers.

  11. #11
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    How are you putting the tire back on? Just hands, or are you using tire tools? It's pretty easy to pinch flat a new tube if you're not careful while mounting it. Like zebrahum said, check by pumping up the tube before putting it in. It'll help pinpoint where the problem is.

  12. #12
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    I always partially inflate the tube before installing it. It helps give the tube some shape to get it in place a little easier.
    Joe
    2003 KHS Alite 4000 26" Hardtail - XC, All mountain, blah blah blah.. I just ride.

  13. #13
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    This is a great idea!!! I'm always worried I'll miss something with my hands

  14. #14
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    I put my inner tubes in a ziploc sandwich bag. The plastic provides a low-friction container to prevent a abrading the tube. Oh, and carry patches.
    Please donate to IMBA or your local chapter. It's trail karma.

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