10-52 teeth across twelve cogs. That's the gear range SRAM's XX1 Eagle cassette delivers, and it's the reason 1x drivetrains work for everything from steep fire road climbs to full-speed descents. The XG-1299 sits at the top of SRAM's Eagle cassette lineup, built for riders who want the widest range with the lowest weight penalty.

The construction method matters here. SRAM machines the XG-1299 from a single block of steel—all twelve cogs come from one piece of material rather than individual cogs pinned or riveted together. This X-Dome construction eliminates the weight of carrier spiders and fasteners while maintaining the cog spacing precision that keeps shifting crisp across the full 520% gear range. The machining process also allows for deeper tooth profiling than stamped cogs, which translates to more positive chain engagement under load.

The cassette runs on SRAM's XD driver body, which uses a smaller diameter than traditional freehub bodies. That smaller diameter is what makes the 10-tooth small cog possible—a standard Shimano HG freehub can't physically fit a cog smaller than eleven teeth. If your rear hub doesn't already have an XD driver, you'll need to swap the freehub body before installation. Most major hub manufacturers offer XD drivers as accessories.... Read More