Intro
It hasn’t been a secret that SRAM has been working on a DH version of their Transmission groups, and today it’s breaking cover. Let’s check it out.
XX DH Transmission Derailleur
- MSRP: $700 / €765 / £680 (Battery not included)
- Stated Weight: 426 g
The XX DH Transmission derailleur shares a lot of its design and features with the 12-speed Eagle Transmission derailleurs, just repackaged for a narrower range 7-speed DH cassette. It mounts to a UDH-compatible frame in lieu of the derailleur hanger, just like the 12-speed versions, and uses a similar installation procedure. Once again, there are no limit or B-tension screws to be found; the derailleur travel limits are fixed, and the B-tension is essentially set when you bolt the derailleur to the frame.
The XX DH derailleur uses the same AXS batteries that have been used across SRAM’s various wireless components for as long as those have existed, with the updated mounting position on top of the derailleur that debuted with the GX T-Type derailleur a few years ago. The XX DH derailleur’s cage is, of course, much shorter than the 12-speed Eagle versions, and the pivot points and other finer details have been tweaked to suit the smaller DH cassette, but the overall form factor is broadly similar. The XX DH derailleur also uses the same chain-damping clutch as the AXS T-Type derailleurs.
XX DH Transmission Cassette
- MSRP: $500 / €545 / £485
- Stated Weight: 150 g (XD mount) / 144 g (XD Slim mount)
The XX DH Transmission cassette is a 7-speed design with 10-24 tooth gearing. In keeping with SRAM’s other high-end cassettes, it’s machined from a single block of steel, and is designed to be used with a Flat Top T-Type chain only. Like the other Transmission cassettes, it sits slightly farther outboard than a standard cassette, using the extra space that’s freed up by the derailleur’s Direct Mount design, and thus is only compatible with the XX DH Transmission derailleur.
The XX DH cassette is offered in two different mounting configurations — SRAM’s longstanding XD driver, and a new XD Slim version. The XD Slim driver is pretty much what it sounds like — a narrower version of the XD driver that just has room for a 7-speed cassette, while the standard XD version includes a spacer to take up the extra room that’s needed to run a 12-speed cassette on an XD driver.
The idea of the HG Slim driver is to allow for wider hub flange spacing to make for a stronger rear wheel with more even spoke bracing angles. Details on the availability of XD Slim hubs are scarce, but SRAM says that it’s the same width as narrower 7-speed HG freehub bodies (e.g., as used on Hope’s Pro 5 DH hub), so it should be possible to make an XD Slim driver that retrofits to those.
XX DH Crankset
- Versions Offered: 150, 155, 160, & 165 mm arms; 32, 34, & 36 tooth chainrings
- MSRP: $450 / €490 / £440
- Stated Weight: 701 g (configuration not specified)
The XX DH Crankset looks a whole lot like the X0 Transmission crank that’s been around for a few years now. Both use forged aluminum arms with a distinctive cutout in the middle. The XX DH version is beefed up and features some extra machining on the ends of the crank arms, so they don’t show scuffs and wear as quickly.
SRAM’s existing DUB spindle diameter and eight-bolt chainring mount carry over. The XX DH crank is also offered in two spindle widths — DUB DH for 83 mm bottom bracket shells and their press fit equivalents, and DUB Wide for 73 mm spaced frames with 148 mm Boost hubs. The DUB DH versions come with a beefier chainring that produces a 56.5 mm chainline, while the DUB Wide ones come with the existing XX T-Type chainring and get a 55 mm chainline.
Both versions are offered in 150, 155, 160, and 165 mm long arms with 32, 34, or 36-tooth chainrings.
Controllers
Chains
- MSRP: $50 / €60 / £55
- Stated Weight: n/a
- Blister’s Measured Weight: 285 g
