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.
mtn. biking 101
2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
3. Don't belive the hype. Just because your favorite rider or best friend rides a certain bike, that doesn't mean that's the best one for you. Have an open mind and be realistic about your needs and ability.
Results 1 to 11 of 11
  1. #1
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    Flat tire but can't figure out why!?!?!

    I experienced my first flat tire today. I was bummed when I got home from work because I was going to go on a ride, but my back tire was very low. My tires/tubes were perfectly fine when I went riding on Monday, but for whatever reason, my rear tire was VERY low today. So, I took the tire/tube off, inspected them both and for the life of me could not figure out why it was so low. I put soapy water all around the tube and couldn't find any leaks anywhere and I'm 100% positive there was nothing in the tire either. My only thought is that it may have been the valve stem? I didn't see anything obvious wrong with the valve stem. It's just doesn't make sense to me because I've only ridden this brand new bike a couple times on pavement. Anyways, despite the fact that I couldn't see anything wrong with the tube, I replaced it. For grins, I inflated the old tube and I'm going to keep a close eye on it to see if it loses air like it did the first time.

    Any ideas or suggestions?

  2. #2
    ~Disc~Golf~
    Reputation: highdelll's Avatar
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    bathtub or deepsink
    Honestly... ahh I give up

  3. #3
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    sounds like a very slow leak. It might just be a valve defect. It's not a big deal other than needing to pump it up each time for a ride. I've gone through several tubes with valve defects and it hasn't affected my ride.

  4. #4
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    I did that, too. I put the tube in the bath tub and no bubbles. I'm stumped.

  5. #5
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    Quote Originally Posted by captainjoon
    sounds like a very slow leak. It might just be a valve defect. It's not a big deal other than needing to pump it up each time for a ride. I've gone through several tubes with valve defects and it hasn't affected my ride.
    Hmm -- maybe that's the problem then. Something like that would probably be next to impossible to verify, right?

  6. #6
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    If it's a very slow leak where it goes flat in several days to a week...then it is highly unlikely that there is a puncture, even a small one. It has to be in the valve area and it will be very difficult to detect a leak that slow.

  7. #7
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    Quote Originally Posted by captainjoon
    If it's a very slow leak where it goes flat in several days to a week...then it is highly unlikely that there is a puncture, even a small one. It has to be in the valve area and it will be very difficult to detect a leak that slow.
    Ok -- thanks for the input. I guess I'll chaulk this one up to bad luck with a new bike. It's funny because just yesterday, I stopped by my local bike store to pick up a mini pump and a couple spare tubes! Glad I did!

  8. #8
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    Probably not possible to diagnose. Could be an issue with the valve, somebody malicious playing a trick on you, user error (depending on valve type), ...

    I'd pump it up and check it once a day. If it doesn't seem to lose air... use as spare.
    "Lorem ipsum dolor sit amet, consectetuer adipiscing elit." - And I agree.

  9. #9
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    Quote Originally Posted by Kaba Klaus
    Probably not possible to diagnose. Could be an issue with the valve, somebody malicious playing a trick on you, user error (depending on valve type), ...

    I'd pump it up and check it once a day. If it doesn't seem to lose air... use as spare.
    Yah, I'm going to try that. It wasn't completely flat -- about 1/2 flat, so I guess that's a pretty good indicationg that it's the valve.

  10. #10
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    Possibly, you check the tube with air pressure too low for you to see the bubbles. Pump it up as much as possible, then check in water again.
    I don't think, using an unreliable tube as a spare is a good idea, it may fail exactly when you need it most.
    If you have sealant in the tube, it may have clogged the hole already. To make sure, pump it up (say, with a hand pump at home, then ride to a gas station and inflate to the upper limit) and rotate the wheel several times, with abrupt stop.

  11. #11
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    Reputation: Joel.'s Avatar
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    Slow leaks means it's time for a new tube. I had one not long, there was no way I could find it after a few attempts at looking and I got sick of pumping the tyre up everyday.

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