SRAM DUB PressFit Bottom Bracket - BB89.5/BB92 89/92mm MTB SuperBoost + BLKSRAM DUB PressFit Bottom Bracket BB89. 5 BB92 89 92mm MTB SuperBoost + Black. The SRAM DUB bottom bracket series has a simple job to connect crankarms and protect the smooth long lasting application of power to the drivetrain. SRAM engineered the oversized DUB spindle to work across every bottom bracket standard simplifying crankarm compatibility. Designed for use with SRAM SuperBoost+ Cranksets Gutter Seal Technology drastically improves sealing