How to Fix a Bike Tire Stem

You can fix a leaky bike tire stem if it is a Schrader valve. A Schrader valve is the kind that car tires have, which are very common on mountain bikes, cruisers and economy road bikes. If the rubber part of the stem is cracked or leaking from the base, it is unrepairable, but if the stem is leaking from the nozzle where you put in the air, you can take out the valve with a valve core remover, clean the valve and put it back in. That's usually all it takes to fix a leaky bike stem.

Things You'll Need

  • Valve core remover
  • Cotton swab
  • Spray oil
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Instructions

    • 1

      Take the cap off the valve stem.

    • 2

      Insert the forked end of the valve core remover into the end of the stem. Push it down into the stem, twisting it slightly as you go until you feel the small fork at the end of the stem engage the valve. You will know it's engaged when it stops turning.

    • 3

      Twist counterclockwise on the end of the valve core remover. When the valve comes loose, gently pull the core remover out, pulling the small spring-loaded valve with it. The valve will stay on the end of the core remover.

    • 4

      Spray a small amount of lubricating oil such as WD-40 on a cotton swab and insert it into the opening where the valve core came out. Clean the inside of the valve stem, scrubbing it up and down with the cotton swab to remove any grit or sand.

    • 5

      Lightly spray the valve with lubricating oil while it is still hooked onto the end of the valve core remover. Use your cheeks to blow air across the valve. Look at it closely; if you can't see any grit or sand, insert it back into the stem while still hooked to the valve core remover. When it bottoms out, twist the end of the valve core remover clockwise until it stops. Fill the tire with air and put the cap back on the stem.