Valve Stem Cap

Discussion in 'Touring Models' started by franka, May 22, 2016.

  1. franka

    franka Active Member

    This may seem like a very silly question but when asked I usually get a 50/50 split on the answer. What's best to use to prevent air from escaping through the valve stem, a cap with an O ring or one without? Some say the O ring can compress the valve needle forcing air out others say O ring only.
  2. 76_shovel

    76_shovel Member

    This might seem like a very silly answer...
    If your valve stem is leaking air, why try to fix with a cap ?
    replace the valve stem with one that does not leak...
    Breeze3at likes this.
  3. dbmg

    dbmg Guest

    By using the valve cap with out O ring it prohibits moisture entering valve and possible slight air loss when hitting bump in the road...... The O ring sits on the top of threads. Can not see how it could depress valve....
  4. franka

    franka Active Member

    Sorry, I should have explained this in more detail. It's not leaking the question should have been stated as "what's best to prevent leaks"?
  5. dbmg

    dbmg Guest

    Post #3 covers it for me....;)
    But it should read using valve cap with O ring not without. Unable to get sentence corrected.
  6. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

    I've always used a regular cap on all my vehicles, never had issues with lose of air pressure.
  7. joel

    joel Senior Member

    The valve stem caps on my bike have o rings inside them. My front was loosing air and I did find the core / schrader pin was bent. However, Still needed and new tire to stop the leak on the new bike.
  8. Harttoo

    Harttoo Senior Member

    Wow! You made Me go look.I never realized there was an o ring in there.If they leaked I replaced the valve.:eek:
  9. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    I don't think the oring in the cap is so much to prevent air leaking out (although it may help with that) as to prevent water and crud from getting in to the top of the schrader valve.

    If the tire is losing air faster then normal, then check to make sure the schrader valve is fully seated with a schrader valve wrench. You can check that the schrader valve is not leaking with a bit of liquid soap (or just common spit!!). If still leaking, then replace it.

    Other leaks are more likely: nails, screws, glass bits, or other sharps that have penetrated through the tread into the tire.

    Lastly if the tire has been replaced recently and is leaking air, then the bead may not be fully seated on the rim. This should be corrected immediately with as little riding as possible until done especially if it is the front tire.


    Last edited: May 24, 2016
    gator508 likes this.
  10. HDDon

    HDDon Experienced Member Contributor Retired Moderators

    It is my understanding that the valve caps are there to prevent trash from getting to the valve. The valve is there to seal the air in. If you take the cap off and do the spit test on the valve stem and get air bubbles it's time to remove the inner portion and clean or replace.
    gator508 likes this.