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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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.
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  1. #1
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    Presta valve question. ?

    hey guys

    have presta valves on my new bike , used to schrader. I hear different answers for if u need the nut that u tighten to the rim. Do i need these nuts ?

    what do u guys do on your bikes with them ?

    thanx for any help

  2. #2
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    I ony hand tighen them.
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  3. #3
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    I typically don't use the nut. If I get a flat on the trail and have to use a hand pump I will use the nut to prevent the stem from moving around and cutting the tube during inflation. If I use the nut, I keep it snug, not tight. If it is too tight, it can pull the tube up into the rim and cause a rip in the tube.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  4. #4
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    Thanx for the info guys !!!!!

  5. #5
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    Quote Originally Posted by zebrahum View Post
    I typically don't use the nut. If I get a flat on the trail and have to use a hand pump I will use the nut to prevent the stem from moving around and cutting the tube during inflation. If I use the nut, I keep it snug, not tight. If it is too tight, it can pull the tube up into the rim and cause a rip in the tube.
    1+ that about sums up my use of it.

  6. #6
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    I throw them away - never used them.

  7. #7
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    Not using the nut, and so far no issues.

  8. #8
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    Another question about Presta Valves ??

    Hi, Couldnt find an answer in the search, so I'll just ask here. Man, I am runnin into some real inconsistencies with Presta, never had issue with Schraeder. Ok, here is the questions/problems.

    1) I have a Redline Urbis, presta valves, and I can fill the tires on that bike with my air compressor, and a screw on Schraeder type adapter. But I CANT fill it with a Lezyne pressure drive (presta only) hand pump. No go. Not even one stroke. Just pressurizes the air hose on the pump. WHY ?!?!

    2) Have a Fat bike, and SAME pump (Lezyne pressure drive) will fill both of those tires no problem. But they run low pressure, so I bought a highly reccomended low pressure tire gauge (20psi) max. It needs the Schraeder type adapter. It will only get a reading off my rear tire. Not the front. Both the valves work properly, inflate properly, and look the same. But it will not take a reading from front tire.. Why ?!?!

    Its just an air valve, but seriously, whats the deal ? A presta wont fill with a presta only pump made to accept only presta ? Yet same pump will fill other Presta's ? A presta that can be filled with a presta only pump, but not be measured for air quantity ?

    Weird...any suggestions ?

  9. #9
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    Quote Originally Posted by Portly Throckmorton View Post
    Hi, Couldnt find an answer in the search, so I'll just ask here. Man, I am runnin into some real inconsistencies with Presta, never had issue with Schraeder. Ok, here is the questions/problems.

    1) I have a Redline Urbis, presta valves, and I can fill the tires on that bike with my air compressor, and a screw on Schraeder type adapter. But I CANT fill it with a Lezyne pressure drive (presta only) hand pump. No go. Not even one stroke. Just pressurizes the air hose on the pump. WHY ?!?!

    2) Have a Fat bike, and SAME pump (Lezyne pressure drive) will fill both of those tires no problem. But they run low pressure, so I bought a highly reccomended low pressure tire gauge (20psi) max. It needs the Schraeder type adapter. It will only get a reading off my rear tire. Not the front. Both the valves work properly, inflate properly, and look the same. But it will not take a reading from front tire.. Why ?!?!

    Its just an air valve, but seriously, whats the deal ? A presta wont fill with a presta only pump made to accept only presta ? Yet same pump will fill other Presta's ? A presta that can be filled with a presta only pump, but not be measured for air quantity ?

    Weird...any suggestions ?
    It's dependent a lot on the make of the tube/presta valve. It's hit or miss using those schrader/presta adaptors.

    Also check the valve core. Sometimes they don't seat right and because of that the tube/tire will not fill properly.

    -S

  10. #10
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    I do use the nut. It holds the valve in place when you're pumping the tube.

  11. #11
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    The Lezyne head is a bit funky to put on and if not engaged properly, it won't depress the brass top of the presta....thus you get the situation you talked about. Play with it a bit when you're not jonesin for a ride to figure it out. Once you get it, it's easy.....but it sure is a PITA at first.

  12. #12
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    Quote Originally Posted by Millfox View Post
    I do use the nut. It holds the valve in place when you're pumping the tube.
    Same here. I run low pressures so without the nut I would have to hold it when inserting the pump.

  13. #13
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    I also use the nut because it holds things in place for inflation. I also use UST tubeless rims/tires and the tubeless valve cores REQUIRE you to use a nut because it seals the valve stem to the rim. I have no choice there. But you can buy unthreaded presta tubes that don't even have a nut. I think they're primarily for deep v road rims that stabilize the valve stem well enough on their own.

    As for problems with pumps, it happens.

    I always push the brass nut and let a little air out before I put my pump head on. On presta valves, that thing can stick (especially so if you have sealant in there). I would imagine Schraeders can clog with sealant, too.

    Occasionally my Blackburn pump insists on pushing air out of the Schraeder end instead of the presta end even when I have it attached to a presta valve. I have to fiddle with it some to get it to work.

    I suspect you're having problems with your valve cores sticking. Push them in to de-stick them before using your pressure gauge or pump.

  14. #14
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    Quote Originally Posted by Portly Throckmorton View Post

    1) I have a Redline Urbis, presta valves, and I can fill the tires on that bike with my air compressor, and a screw on Schraeder type adapter. But I CANT fill it with a Lezyne pressure drive (presta only) hand pump. No go. Not even one stroke. Just pressurizes the air hose on the pump. WHY ?!?!

    Weird...any suggestions ?
    Did you unscrew the tiny nut on top of the Presta valve to open it? Once you have unscrewed it, depress the needle with your finger to open the valve.

  15. #15
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    I just ordered a 4 pack of tubes from Backcountry and they showed up with 3" stems. I'm afraid that if I don't use that nut I'll end up with a stem sticking out through my tire.

  16. #16
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    Quote Originally Posted by Portly Throckmorton View Post
    Hi, Couldnt find an answer in the search, so I'll just ask here. Man, I am runnin into some real inconsistencies with Presta, never had issue with Schraeder. Ok, here is the questions/problems.

    1) I have a Redline Urbis, presta valves, and I can fill the tires on that bike with my air compressor, and a screw on Schraeder type adapter. But I CANT fill it with a Lezyne pressure drive (presta only) hand pump. No go. Not even one stroke. Just pressurizes the air hose on the pump. WHY ?!?!
    I've had issues with presta valves sticking shut. So, after I unscrew the tiny locking nut, I also tap the end of the valve to let a little air out and make sure it is moving and will let air in (or out). On a sticky valve, once you mount the pump, you won't be able to get any air in the tube - at least that was my experience. This may be your issue. I would imagine the compressor may have enough oomph to move that sticky valve but the hand pump does not. Give it a shot.

    I use the presta valve nut, but as with others, only to hold it in place while inflating. Tighten it too much and it will tear a hole at the base of the valve stem. My road bike has one without a nut (made for deep v's which I don't have but is a tube a friend leant me) and it works fine now for 8 months. So, its probably not necessary.

  17. #17
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    Quote Originally Posted by Portly Throckmorton View Post
    1) I have a Redline Urbis, presta valves, and I can fill the tires on that bike with my air compressor, and a screw on Schraeder type adapter. But I CANT fill it with a Lezyne pressure drive (presta only) hand pump. No go. Not even one stroke. Just pressurizes the air hose on the pump. WHY ?!?!
    I've found that I need to feel a little pop which indicates that the top nut releases and begins to accept air into the tube. I have a Lezyne floor drive so I assume that your pump has a similar mechanism. Just keep trying and you should figure it out.
    Free people must travel the road to productive social relations at the speed of a bicycle.- Ivan Illich

  18. #18
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    Quote Originally Posted by mbco1975 View Post
    Did you unscrew the tiny nut on top of the Presta valve to open it? Once you have unscrewed it, depress the needle with your finger to open the valve.
    Hi, Thanks all who answered for the replies, good to know (no offense) that others have had issues as well, and I just didnt get a load of crappy parts and gauges. Yes, I have unscrewed the end before filling, but no, I never tried tapping it to make sure the valve is freed up. So I guess I will just have to play with em.

    Interestingly enough, tonight another Lezyne pump showed up in the mail, a cheap $18 one I ordered for the other bike, and that one WILL work on the redline. So it's a swap. The super cheap pump to fill the 85 PSI tires on the Redline, and the expensive pump to fill the 10-18 PSI tires on the Pug. Whatever.... as long as it works.

    Weird how these things became pretty much an industry standard in the 10 years since I been riding bicycles. I mean, because they are so problematic. And a pain in the a$$. And universally accepted ??

    Thanks again for the replies !!

  19. #19
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    Quote Originally Posted by Portly Throckmorton View Post
    Weird how these things became pretty much an industry standard in the 10 years since I been riding bicycles. I mean, because they are so problematic. And a pain in the a$$. And universally accepted ??

    Thanks again for the replies !!
    *cough* Chinese "standards" *cough*

  20. #20
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    Quote Originally Posted by shibiwan View Post
    *cough* Chinese "standards" *cough*
    Pretty much answers all my questions then, doesnt it ?!?! Ha ! Thanks.... I get it now

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