Ten cogs machined from a single block of steel, plus an aluminum 52-tooth climbing gear — that's how SRAM builds the XX1 Eagle XG-1299, and it's the reason this cassette sits at the top of the mechanical Eagle hierarchy. The 10-52 tooth range delivers a 520% gear range on the XD driver body , giving you the top-end speed of a bigger chainring without giving up bailout gears when the trail kicks up. If you're building an XX1 Eagle drivetrain or upgrading from GX or X01 and want the lightest, most refined cassette in the pre-Transmission Eagle lineup, this is where it lives.

The construction is what separates XG-1299 from cheaper Eagle cassettes. SRAM machines the cluster from a single block of steel — all the cogs come from one piece of material rather than individual cogs pinned or riveted together, which eliminates the weight of carrier spiders and fasteners while maintaining cog spacing precision. The 52T aluminum climbing cog gets pinned to the machined cluster to keep weight down at the low end where the biggest cog would otherwise be heaviest. A titanium nitride finish handles corrosion resistance and chain glide , which matters more than it sounds — it's the coating that gives XX1 its distinctive copper, gold, or rainbow appearance and keeps the finish looking right through wet-weather riding.

Compatibility is straightforward within the Eagle ecosystem. The cassette works with all SRAM Eagle 12-speed chains and requires an XD driver body , and it pairs with GX, X01, or XX1 Eagle derailleurs and shifters — including AXS wireless — without any adjustment beyond a normal drivetrain setup. Worth flagging: this is a pre-Transmission cassette. It does not work with T-Type Eagle Transmission derailleurs (XX SL, XX, X0, GX Transmission), which use their own XS-series cassettes and a Full Mount interface. If you're on a UDH-equipped frame running T-Type, you need a Transmission cassette, not this one. For every other Eagle drivetrain built in the last several years, the XG-1299 drops right in.