The diameter on Presta valve hole is 6.5mm (standard option). The diameter on Schrader valve hole is 8.0mm. All of our rims come standard with a valve hole driller for Presta valves, however, you can request that we drill the rims for the less common Schrader valves. While Mountain bikes will sometime have Schrader valves, it is very unusual to have Schrader valves on higher-end mountain bikes or road bikes.
