Eagle Transmission drivetrains ditched the derailleur hanger and built the mounting alignment into the frame's UDH interface, which means the cassette itself became a critical piece of the shift equation. SRAM's XS-1275 GX Eagle T-Type 12-Speed Cassette sits at the entry point of that ecosystem — it uses the same MINI CLUSTER construction and X-SYNC tooth profile as the pricier XX and X0 T-Type cassettes, just built with heavier materials and finishes to bring the cost down. If you're building a GX Transmission drivetrain or replacing a worn cassette on one, this is the cog set that goes with it.

The 520% range has been optimized with larger 38 and 44-teeth cogs prior to the 52-tooth cog for improved gear steps in the low end compared to earlier 10-52t Eagle cassettes. That reworked low end is where the T-Type cassette actually feels different on the trail — the jump from 44 to 52 is less of a cliff than the old 42-to-52, so you can settle into a climbing cadence without hunting for the right gear. The 10-tooth small cog on the top end keeps the same overhead you'd expect from Eagle for descents and flat pedaling sections.

Construction uses a Pindome design for gears 1-8 and a single piece mini-cluster for gears 9-12 , with nickel-plated cogs and a clearly marked Setup Cog for easier installation . The Setup Cog matters more than it sounds — Transmission setup is done by aligning the derailleur to a specific cog rather than fussing with limit screws and B-tension, so having that reference marked on the cassette itself keeps the process foolproof. The nickel plating also runs quieter than raw steel and holds up to wet-weather corrosion.... Read More