SRAM's XX1/X01 Eagle Ceramic Derailleur Pulley Set is the OEM replacement kit for the 12-speed Eagle rear derailleurs that shipped with ceramic bearings from the factory. If you're running an XX1 or X01 Eagle mechanical or AXS rear derailleur and the pulleys have developed play, grinding, or noticeable drag, this is the direct swap that keeps the derailleur factory-spec. It also fits GX Eagle 12-speed derailleurs if you want to upgrade a GX cage from stock steel-bearing pulleys to ceramic without buying an aftermarket set.

The kit uses a 12-tooth upper (guide) pulley and a 14-tooth lower (tension) pulley — the same asymmetric setup SRAM runs across the pre-Transmission Eagle lineup. The tooth count difference matters at install: the lower pulley is the larger one, and swapping their positions will throw off chain tracking and shift quality. The X-Sync tooth profile carries over from the original pulleys, so chain retention on rough terrain stays consistent with how the derailleur was designed to run.

One thing to confirm before ordering: this set is for the older Eagle platform (RD-XX1, RD-X01, RD-GX with the standard B-bolt cage), not the newer Eagle Transmission T-Type derailleurs. T-Type uses a 14/16-tooth pulley combination and a completely different cage architecture, so the two aren't cross-compatible. If your derailleur is a direct-mount T-Type unit without a B-tension adjustment, you need the Transmission-specific pulley kit instead.