With the new SRAM XX DH Transmission drivetrain, the popular direct-mount system finally makes its way onto downhill bikes. Downhill racing was a strong focus in its development, as SRAM’s primary goal was to maximise power transfer to the track and enable measurable time gains between the start gate and the finish line by eliminating previous shift interruptions.
However, we also ask ourselves how relevant these – admittedly very specific – performance advantages are for everyday riders. The extremely direct shifting performance and the last tenths of a second in a sprint play only a minor role for recreational riders. A different aspect is far more interesting: the added robustness. Especially for everyday bike park scenarios with lifts and shuttle trucks, rock strikes and crashes, riders clearly benefit from the massive construction and protected design of the new Transmission. In addition, it’s designed to keep the drivetrain noticeably quieter at the rear by maintaining very high chain tension.
The new SRAM XX DH Transmission drivetrain in detail
The new SRAM XX DH Transmission drivetrain is now also based on the well-known full-mount interface of the T-Type platform and relies on a direct-mount rear derailleur that attaches directly to the frame. While a conventional derailleur hanger is no longer required, a UDH-compatible dropout is necessary. As with the GX Transmission generation, the battery sits on top between the stays and is therefore even better protected. In addition, compared to other T-Type models, the derailleur is positioned further inward towards the chainstay, which means it hangs higher and is therefore less vulnerable.The cage features the typical slight bend, complemented by revised pulleys with more robust teeth. Overall, the DH rear derailleur appears even more robust than the already massive T-Type models. Many components are replaceable, including the skid plate (plastic cover), the outer parallelogram and the cage itself.
Inside, it relies on the Type-4 derailleur clutch carried over from the latest T-Type generation. However, due to the shorter cage arm of the XX DH, more force is required to move it, resulting in higher chain tension. This translates into a noticeably quieter drivetrain — a welcome relief on rough downhill tracks or lapping the bike park.
Also entirely new is the 7-speed XD Slim cassette. Its position allows the derailleur to operate further inward. At the same time, it enables a hub with a symmetrical spoke angle, making the wheel more stable and easier to service. Technically understandable, but these slim cassettes only fit specific hubs. Although the installation width remains the same, the freehub interface doesn’t. This means that hub and slim cassette are exclusively compatible with each other, and SRAM are introducing a new standard for downhill rear wheels. Anyone upgrading or buying a new bike should therefore carefully check which hub is installed. In addition, there’s also a “standard” 7-speed T-Type cassette that is compatible with common hubs and XD freehubs. As with all T-Type cassettes, the X-SYNC tooth profile with shift ramps is used. If you want to dive deeper into cassette technology or the electronic mapping of the T-Type series, you can find the details in our Transmission test of the 12-speed version.
The crank choice is interesting: despite the XX label, SRAM rely on aluminium instead of carbon. The reason is increased impact resistance, which we fully support. Lengths from 150 to 165 mm are offered – clearly tailored to downhill use. The matching chainring features reinforced teeth to prevent premature bending and is available with 32, 34 and 36 teeth. The system is also O-Chain-ready, which comes as no surprise after SRAM acquired O-Chain. However, there’s no option to mount a bash guard directly to the chainring on the XX DH drivetrain.
Some components remain unchanged: the XX Eagle Flat-Top chain remains the same, and shifting is handled via a classic AXS Ultimate Pod. In terms of weight compared to a conventional 7-speed groupset, there’s little difference. The new cranks are slightly heavier, while the T-Type cassette is lighter. The T-Type rear derailleur gains weight, but a traditional mech hanger and shift cable including housing are eliminated. As a result, the weight increase is so small that, according to SRAM, even extensive testing revealed no noticeable difference due to unsprung mass.
| Component | Weight | Price UVP |
|---|---|---|
| XX DH Transmission Rear Derailleur | 452 g | € 765 |
| XX DH Transmission Cassette | 145 g | € 545 |
| XX Eagle Transmission Flattop Chain | 242 g | € 240 |
| XX DH Transmission Crankset + O-Chain and 32T Chainring | 853 g | € 695 (without O-Chain) |
| AXS Pod Ultimate Controller | 48 g | € 240 |
In terms of pricing, the SRAM XX DH Transmission remains at the expected premium level. Individual prices are € 765 for the rear derailleur, € 490 for the cranks, € 545 for the cassette, € 112 for the chainring, € 150 for the chain, € 240 for the AXS Pod and around € 45 for the battery. This totals € 2,347. We do not yet have current pricing for a complete drivetrain, but the DH version is therefore priced at the same level as the regular XX Transmission counterpart. Installation remains simple and straightforward, as with all previous T-Type models.
The new SRAM XX DH Transmission drivetrain on test
We also rode the new SRAM XX DH Transmission drivetrain during the long RockShox and SRAM press camp in New Zealand. It was mounted – alongside the new BoXXer fork and the new Vivid DH shock – on a Canyon Sender. This allowed us to spend three full days on demanding downhill tracks in the Queenstown Bike Park and on the very fast track at Coronet Peak.
The Canyon cockpit now looks pleasantly clean thanks to the AXS Pods, with only the MAVEN brake cables visible. In combination with the Infinity Clamp, the pods can be positioned freely for improved ergonomics. The shorter cage with its high preload is immediately noticeable. When moving it by hand, you instantly feel the increased force required – and accordingly high is the chain tension while riding. On the trail, this results in total silence from the drivetrain – No chain slap, no unnecessary noise, even in rough high-speed sections.
Shifts are crisp and defined, as is typical for T-Type. Over the three days, we didn’t experience a single poor gear change – neither under load nor in rough sections. We particularly like how closely the rear derailleur sits to the chainstay. It protrudes less outward and therefore appears significantly better protected against rock strikes or crashes. How close it actually sits to the frame depends strongly on the specific bike – on the Sender, the integration was very successful. Of course, we also tested how robust the derailleur truly is and made solid contact with a few rocks. Apart from some scratches on the parallelogram and the almost endearing whirring sound of the derailleur as it returned to its original position, the XX DH derailleur handled everything without issue.
Conclusions about the 2027 SRAM XX DH Transmission drivetrain
The new SRAM XX DH Transmission delivers exactly what it promises: an extremely quiet drivetrain, crisp shifting true to T-Type form, and a derailleur that sits close and securely against the chainstay. For most riders, the added value lies less in sprint time gains and more in robustness, high chain tension and the modular design with many replaceable parts. However, the high price point and the current lack of more affordable model variants may deter some buyers.
Tops
- Robust and securely positioned on the bike
- Very quiet
- Precise and reliable shifting
- Clean look
Flops
- Only available as an expensive XX model
- XD Slim cassette requires a specific hub
For more information, visit the SRAM website.
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Words: Peter Walker Photos: Sven Martin, Callum Wood