The SRAM XS-1299 Eagle Transmission Cassette is the cornerstone of precise, load-resistant shifting performance in the Eagle Transmission system. Featuring a full X-SYNC design, it delivers seamless inboard and outboard shifting—even under high pedaling force—making it ideal for aggressive riding. This is SRAM’s lightest 10-52T cassette ever, thanks to a new-generation structure that blends a hardened, fully machined steel X-Dome for cogs 1–9 with an ultra-lightweight aluminum Spider Cog for cogs 10–12. The result is a high-strength, long-lasting cassette that also sheds grams for performance-focused riders. With optimized gear steps in the low range (38T and 44T before the 52T), it ensures better cadence control and more usable range during steep climbs.

Purpose-built for T-Type chains and Full Mount derailleurs, the XS-1299 is engineered for perfect alignment and integration, improving drivetrain precision and lifespan. The massive 520% gear range is matched with a 55mm chainline to reduce chain angle and friction, supporting smoother shifts and increased durability. A clearly labeled Setup Cog simplifies installation, making the process intuitive and repeatable. Compatible with the widely adopted XD driver body, the XS-1299 blends cutting-edge shifting performance with practical compatibility and reliability. While not suited for E-MTBs, this cassette is a top-tier choice for riders seeking the pinnacle of mechanical efficiency and seamless wireless shifting integration.