Originally Posted by
Raleigh71
Your friend who drilled out his Presta vale holes to Schrader size has some insight, I have top admit.
If the Presta valve was threaded, and you had the nut cinched down to the level of the rim I can't see the valve stem going anywhere even with a flat.
better yet, cut them to be under the rim, and use a stepped presta nut (like come with Continental tubes) to keep the valve centered and you would never know there is a converter at all. Very clean. The primary reason for the grommet is to keep the tube from herniating at very high pressures.
