Chromag BZA 35 Bar and Stem Revolution Bikes March 19, 2014 NEWS AND REVIEWS The BZA 35 is strong, light, and burly. Featuring the new 35mm interface and weighing a perfect 165g this stem is light yet extremely stiff for positive control. The 35mm diameter clamp surface allows us to build a DH strength bar with unidirectional carbon weave that is stiff, as requested, and has excellent vibration absorbing properties. BZA 35 Carbon bar. BZA 35 Stem.