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  1. #1
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    Valve Extender leaking way too much

    I purchased Conti Valve Extenders for my new tubular Veloflex Roubaixs. Tires go entirely flat within 3-4 days. I sealed the threads with teflon tape at the base and at the top when I inserted the removable core.

    Yet the extenders leak like crazy.

    Luckily, I was somehow able to unscrew the extenders (which connected deep inside my rims where I can't get to them). I was worried I had wasted the tape/glue job on the tubulars by using the Conti Extenders.

    My question: are there any extenders that are known to work really really well in terms of leaks?

    I am looking at the SILCA PVC Extender right now.

    Any other recommendations.
    Last edited by udreks; 08-27-2017 at 04:35 PM.

  2. #2
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    I don't have conti, I think they're Vittoria. Anyway it took me along time to understand this. When I first put them on I screw the extender core in as to tighten. Once screwed in I push the extender core down. There's a small cap like arrangement at the bottom of extender core that friction fits over the tire core. Now loosening the extender core opens the tire valve, tightening the extender core tightens the tire valve. No leaks and it works great. Until I figured this out I was very disappointed with the extenders, but that's because I wasn't using them correctly.

  3. #3
    'brifter' is a lame word.
    Reputation: cxwrench's Avatar
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    I have to ask, cuz...you know. First time w/ these tires? If so do you know they have latex tubes that will leak down like you're saying within a few days to a week? If you've teflon taped as you say it's most likely not the extenders. Not that I'm doubting the level at which you know your ****, but it needs to be asked.
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  4. #4
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    Yes, first time with tubs.

    It's funny--someone passed on their carbon rim tub wheels to me gratis. I did a lot of reading. But nowhere did anyone mention that that they will lose air in 3-4 days.

    Thanks for the post. Because I am going kind of crazy at the thought of removing the tape/glue job to put some new extenders in.

  5. #5
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    Pump them up to correct pressure before every single ride. Don't forget.

    That's the way it is.
    use a torque wrench

  6. #6
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    Quote Originally Posted by udreks View Post
    Yes, first time with tubs.

    It's funny--someone passed on their carbon rim tub wheels to me gratis. I did a lot of reading. But nowhere did anyone mention that that they will lose air in 3-4 days.

    Thanks for the post. Because I am going kind of crazy at the thought of removing the tape/glue job to put some new extenders in.
    So...what cxwrench said and...it's not the sew ups (tubulars) but the latex tubes inside. Just making sure. There are sew ups that have butyl tubes which don't lose "air" like those with latex.

  7. #7
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    It's what keeps me away from latex.

    I'm just too lazy.
    use a torque wrench

  8. #8
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    Quote Originally Posted by woodys737 View Post
    So...what cxwrench said and...it's not the sew ups (tubulars) but the latex tubes inside. Just making sure. There are sew ups that have butyl tubes which don't lose "air" like those with latex.
    So long as the valve extender is not keeping the tube's valve permanently open, the valve extender should not be the issue.

    What brand tubulars are you using? Some brands use butyl tubes (like Conti) which leak down very slowly, while others (like Vitoria) use latex tubes which can be flat in days.

  9. #9
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    I've not ever used tubulars... but I have used latex tubes in cotton clinchers with valve extenders. There are two possible things going on here, as mentioned earlier in other threads. First, latex tubes leak air... they're porous and under high pressure they leak air. The latex tubes in my high end clinchers might last 3-4 days and still retain a decent pressure, but I always check and pump before every ride.. I do this with butyl tubes as well though, so nothing new. Second, I've learned that once you screw the extenders on, you can't unscrew them... it seems that some people view the extenders as a removable piece, there just to make it easy to connect the pump head and then be removed. In my experience, that is not the case, once they are in place, they should be treated as if they're part of the valve. Once you unscrew them and break the seal of the sealing tape,
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  10. #10
    'brifter' is a lame word.
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    Quote Originally Posted by RHankey View Post
    So long as the valve extender is not keeping the tube's valve permanently open, the valve extender should not be the issue.

    What brand tubulars are you using? Some brands use butyl tubes (like Conti) which leak down very slowly, while others (like Vitoria) use latex tubes which can be flat in days.
    You didn't read the OP very thoroughly. Go back and read it again.
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  11. #11
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    The best extenders use the tube's existing valve core.
    It requires removing that core and inserting in the extender.
    Then the extender screws into the "coreless" stem.
    I like the one from Enve. Not sure if the Conti version operates in this manner.
    And, yeah, all Veloflex tubs use latex, which lose at least 10psi each twelve hours.

  12. #12
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    Thanks everyone. Yes, I'm using Veloflex Roubaix, latex.

    And the Conti Extender is the one for use with a removable core. Which is what I did.

    I'm going to simply pump everyday unless I find that too much is being lost on my rides, and then I'll try another extender. ENVE is the same as the SILCA I was looking at.

  13. #13
    'brifter' is a lame word.
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    Quote Originally Posted by udreks View Post
    Thanks everyone. Yes, I'm using Veloflex Roubaix, latex.

    And the Conti Extender is the one for use with a removable core. Which is what I did.

    I'm going to simply pump everyday unless I find that too much is being lost on my rides, and then I'll try another extender. ENVE is the same as the SILCA I was looking at.
    If the extender is taped and tight that's not the problem. It's the latex tubes.
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  14. #14
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    Umm.....latex tires lose about 10% of air about every 6 hours. I cant think of a single latex tubular the DOESN'T go flat in about 3 days. It has **NOTHING** to do with your extenders. If that's not something you wanted to deal with, then you should've bought Conti's.
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