The Niner BioCentric II makes adjustments easy across a wide range of gears and eliminates the need for adjustable dropouts, giving the cleanest possible solution for singlespeed use. No bolt on hubs, no chain tensioners cluttering your ride, no brake adjustments with gear changes.
The Niner Biocentric II requires a BB shell ID of 55mm, and 68mm wide. This part cannot be returned.
The BioCentric II offsets the bottom bracket spindle 8.5mm from center, offering greater range of adjustment compared to a more traditional EBB setup. More offset is a boon when changing gears without having to change chain length and it allows riders to make more noticeable changes to frame geometry via BB position.
Traditional EBB units are held in place with set screws that can become difficult to finely adjust over time, or expansion wedges that can deform the bottom bracket shell of the frame. Split BB shells that clamp an EBB can stretch or ovalize. The BioCentric II avoids these troubles by using two bolts to apply a clamping force on the outside edges of the BB shell, eliminating the possibility of ovalizing or indexing the shell itself. Secure, quiet, easy to install and adjust, the BioCentric II will change your ideas about singlespeed drivetrain setup and maintenance.