Schraeder to Presta Rim Insert

Many bicycle rims are over drilled for Schrader. When the sharp edge of the rim cuts into the tube, it can't be patched. This part fills that space with smooth edges to stop this from happening.

Version A is the "standard" size 0.325".
Version B is the "large" 0.375"

note while installing the minor detail of the saddle interface to the rim. If it doesn't sit all the way down, turn it 90 degrees and try again.

I've use the ones you can buy at the bike store as picture. But for some wh