Bottom brackets have some of the highest torque specifications of any component on a bicycle. Despite this, some bottom bracket cups feature tool interfaces that allow only a few millimeters of engagement, which can be problematic when attempting removal or installation. Solution: The Park Tool Bottom Bracket Tool Retention System. Used in combination with nearly all Park Tool bottom bracket tools, the BBT-RS employs a spring tension system to apply constant, adjustable pressure to the tool, ensuring full engagement with the tool interface and preventing slippage.