XX Downhill AXS Transmission Rear Derailleur

What Our Gearhead® Experts Are Saying:

"I’ve installed a lot of Transmission systems, and this one is purpose-built for gravity. The geometry is completely different—shorter cage, tighter profile—and it holds chain tension incredibly well. Shifting under full sprint feels seamless, and the hangerless Full Mount makes alignment almost foolproof."

When milliseconds separate qualifying from going home, we need a derailleur that never asks us to ease off the pedals. The XX Downhill AXS Transmission Rear Derailleur is engineered specifically for gravity racing, delivering full-power shifting under load through SRAM’s 7-speed T-Type platform. Whether we’re sprinting out of the start hut or driving into the final split, it maintains continuous chain engagement so momentum never stalls.

Its Full Mount hangerless interface secures directly to UDH-compatible frames, eliminating traditional derailleur hangers and dramatically improving structural integrity. In the event of an impact, the system rotates rearward instead of bending a hanger, preserving alignment. The derailleur geometry is purpose-built for downhill: a shorter parallelogram, compact b-knuckle, smaller pulleys, and a DH-specific Inline Cage reduce leverage and increase robustness. The Type 4 damper, shared with other Transmission platforms but operating under higher effective tension due to the shorter cage, minimizes chain slap and keeps the drivetrain exceptionally quiet in high-speed rock gardens and braking bumps.

Designed exclusively for T-Type chains and the 7-speed XX DH cassette, it integrates Cassette Mapping and AXS firmware for faster shift intervals and uninterrupted power transfer. Replaceable skid plates, a rebuildable thread-on cage assembly, and serviceable outer links ensure race-ready durability. For gravity riders demanding precise alignment, silent control, and uncompromised shifting at full throttle, this derailleur sets the new benchmark for downhill performance.