CeramicSpeed's Oversized Pulley Wheel System X makes for a drivetrain and efficiency upgrade worthy of world-class racing. Oversized 14-tooth and 18-tooth upper and lower pully wheels ensure smooth running and are based on high-quality ceramic bearings. It features less friction in comparison to standard pulley wheels and makes for power savings, and a robust cage with carbon fibers keeps off the grams. The metallic coating of the bearing races further improves performance and increases durability.