The XX DH transmission is designed exclusively for downhill use. The drivetrain is tuned for maximum shifting performance under full load, uncompromising robustness, and remarkably quiet operation. The idea behind it is simple: no time should be lost in a race just because you have to take your foot off the pedals briefly to shift gears. Especially in downhill racing, where milliseconds can make all the difference, every shift with classic systems often costs noticeable speed. The XX DH transmission relies on AXS firmware-controlled shifting sequences and cassette mapping to keep the chain constantly and securely engaged. At its heart is a downhill-optimized 7-speed cassette with 10 to 24 teeth and X-SYNC tooth profile. The gradation is deliberately race-oriented, with small jumps so that the power is transferred precisely to the rear wheel. This is complemented by the Ful-Mount rear derailleur, which, as usual, does not require a derailleur hanger and wraps around the frame on both sides. It is positioned as far inside as possible, which provides better protection from external influences and allows it to move backwards in the event of an impact. As with previous Transmission models, key components are replaceable, including skid plates, the outer parallelogram link, and the derailleur cage. A Type 4 shock and the compact, downhill-optimized inline derailleur cage increase chain control and keep the system stable even when the trail really shakes you up.

For the cranks, Sram relies on specially developed aluminum arms, whose heavily stressed areas are milled away so that abrasion and stone chips leave fewer marks. Lengths from 150 to 165 millimeters are available, designed for more ground clearance and a harmonious riding experience. The new XX DH T-Type chainring is designed to withstand even rough impacts thanks to its high impact resistance and bending stiffness. If you're looking for even more smoothness in the chassis and drivetrain, you can combine the group with an Ochain chainring adapter. A chainring with a 104-millimeter bolt circle is provided for this purpose. This system reduces pedal backlash while increasing traction and control.

The XX DH transmission also aims for order and space in the wheel setup. Many downhill bikes now use 148 mm wide rear hubs (previously 150 or 157 mm), which means that the rear derailleur and brake disc are further inside, creating more space for the heels. Optionally, the XD-SLIM freehub can be used, which is designed to enable the narrowest possible construction and symmetrical spoke angles for more stable wheels with even spoke tension. Time is also of the essence in the box: the system relies on a quick assembly process based on the principle of prepare, attach, and tighten. And because AXS has been consistently incorporated into downhill bikes for the first time, there are no cables or cable housings, along with the typical dirt and assembly problems. The AXS Pod Ultimate Controller takes care of the shifting on the handlebars. It offers a "click and fire" design with two buttons, extensive ergonomic adjustability, and customizable settings via the AXS app. Visually, the whole thing remains deliberately classic: black anodization, silver milled details, a look that says "racing machine" before the bike even rolls. Sram positions the XX-DH transmission as a race-proven top-of-the-line groupset that has already been used successfully in the World Cup and World Championships. That's exactly where it should play to its strengths, when every cleanly executed gear change can make a difference.

The Sram XX-DH transmission will be available in specialist stores from February 2026.

sram.com/xx-dh-transmission