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Presta valve in Schrader hole?

Discussion in 'Bicycle Mechanics and Repairs' started by beanzontoast, 4 Aug 2007.

  1. beanzontoast

    beanzontoast Veteran

    Location:
    South of The Peaks
    Can it be done? I have a spare rear wheel that takes the Schrader (car) valve, but I'd like to use it with a Presta tube. Bike uses Presta valve on the front wheel and I don't want to end up having to stock / carry round 2 tube types).

    Currently, the Presta rattles around in the hole when offered up, and when I tried inflating it a little, the valve protrudes through the hole so that it won't seat, even when the lock ring is wound right down to the base of the valve.

    Is there an adapter that will reduce a Schrader hole to take a Presta valve, or is it a no-go?
     
  2. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    you can get a little bit of rubber that fits in the hole to fill the gap, but it will be fine even if you don't use the little rubber widget. I have no idea where you can get one though.

    Scwalbe inner tube locking screws have a two step part that fills the gap too, so it sits flush.

    it'll be fine without either though
     
  3. OP
    OP
    beanzontoast

    beanzontoast Veteran

    Location:
    South of The Peaks
    Cheers steve - I'd wondered about putting a spare lock ring on the valve and using one each side of the hole in the rim. It might hold the valve steady - but do you think it might cause problems with the tube at 116psi?
     
  4. punkypossum

    punkypossum Donut Devil

    Apparently some bike shops do have the widgets, otherwise I have been told you can get them from plumbing supply places
     
  5. Pete

    Pete Guest

    I, too, was told by a LBS that a sort of grommet was available, though they didn't have any in stock, and in the end I used the 'lock ring' dodge as mentioned above. I was warned, however, that if a rim is drilled for Schrader it may not be able to withstand typical presta valve pressures, adapter or no adapter. This may be a matter of opinion, still, I wouldn't trust the setup over about 90psi.

    Better to invest in a new rim.
     
  6. P.H

    P.H Über Member

    I do this with all my rims, so I can use either tube. I have some rubber grommets that came from Gearshift, it doesnt look like they're available now.
    My latest Mavic rim (717?) came like this with a plastic insert. I got it from Holts, in Derby, so it'd be worth ringing to see if they have any spares.
     
  7. OP
    OP
    beanzontoast

    beanzontoast Veteran

    Location:
    South of The Peaks
    P.H. - just spoken to them and they're putting a couple aside for me. Huge thanks for the heads up!

    :rolleyes::becool::blush:
     
  8. P.H

    P.H Über Member

    Result :rolleyes:
     
  9. alfablue

    alfablue New Member

    for anyone else, they are available at John Street Cycles for £1 each - http://www.sjscycles.co.uk search for "Mavic Rim Valve hole drilling converter insert - Schraeder to Presta"

    [​IMG]
     
  10. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    you mean £3.50 dont you?

    You forgot SJS postal charges. They have got better, but 2.50 is a tad excessive for a rubber gromit. Most LBS should have them
     
  11. alfablue

    alfablue New Member

    Yes, it is steep for postage for something weighing about 5 grams!
     
  12. OP
    OP
    beanzontoast

    beanzontoast Veteran

    Location:
    South of The Peaks
    The ones P.H. put me on to today cost me...





    (... drum roll...)






    ... 20p EACH!!!!!!! :rolleyes:

    :blush::biggrin::biggrin::biggrin::biggrin:
     
  13. bonj2

    bonj2 Guest

    i don't know why you're all whittering about grommets and what not, i just put my presta tubes in my mate's schrader hole no problem, just do up the little metal collar thingy and it's fine.
     
  14. alfablue

    alfablue New Member

    Another Bonj wind-up I think, but if you do this the tube will eventually fail as the valve seperates from the tube at it's base - been there, had that
     
  15. bonj2

    bonj2 Guest

    That's a bit strong - "I put a presta valve in a schrader hole" - therefore must be a wind-up!
    You say 'eventually'. I think it will probably puncture by other means before that.