Chasing PRs and race podium spots take special equipment. Removing every bit of mechanical drag is important, both mentally and physically, if you want to go as fast as you can. That explains why the pros have their mechanics swap out the standard bearings and parts for upgraded components with ceramic bearings to help provide an edge over the competition. Now you too can get this advantage by hopping up your rear derailleur with CeramicSpeed's 11 Speed Aluminum Pulley Wheels for Shimano, SRAM, and Campagnolo rear derailleurs. Derailleur pulley wheels are some of the fastest rotating parts on your bike and unlike components built to go faster in the wind where you have to be traveling at a fast rate of speed to reap the benefits, drivetrain friction occurs at every speed. The pulley wheels feature the standard CeramicSpeed Bearings that many pro teams count on the eke out a few more watts that's often the difference between first and second. CeramicSpeed designs these pulley wheels to provide the ideal chainline and perform precise shifts and smooth pedaling. In addition to delivering lower friction, CeramicSpeed claims that the durable, 22-gram aluminum wheels last 3-5 times longer than stock pulley wheels. Each kit includes 2 pulley wheels, spacers, oil for maintenance, and a sticker sheet.