Kogel Bearings 12/14T Oversized Pulley Set Shim R9100 Cross - BlkA fresh look at pulley design maximizing pulley size and improving pedaling performance for any derailleur Redesigned shape of the pulley teeth now give better chain retention and accurate shifts every time Updates to newest version include: Increased stiffness using A Shaped pillars between the bearings and teeth, maximized tooth count for every derailleur helps deliver optimal drivetrain performance, and enhanced visual design achieves a more