Originally Posted by
JohnDThompson
Take a cotton ball and run it long the inside of the tire. If there is a foreign object, like the wire mentioned above, it will snag on the cotton ball. Then you can remove it. If the cotton ball doesn't reveal anything, make sure the rim strip is intact, and no spokes are poking through from the rim to puncture the tube.
Turning the tire inside-out will put the inner surface under tension and help open up any small holes where wires or bits of glass may be hiding, making them easier to detect with the cotton ball or my current favorite, a microfiber cloth. The cloth is also larger and will cover an area quicker.