New SRAM derailleur spotted at MTB World Championships

BlackBox components and industry-wide adaptation of UDH spells the end of derailleur hangers

SRAM Eagle AXS BlackBox rear derailleur and drivetrain

Update 21/03/23: SRAM has now officially launched its T-Type Eagle Transmission. Here’s everything you need to know about the SRAM T-Type Eagle.

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A new SRAM prototype BlackBox direct-mount rear derailleur and all-new drivetrain were ridden by SRAM-sponsored riders at the 2022 Cross Country UCI Mountain Bike World Championships in Les Gets.

The new SRAM AXS electronic, wireless derailleur and drivetrain components were fitted to XCO gold medallist Nino Schurter’s Scott Spark RC, as well as being seen on other riders’ bikes from the Canyon, Specialized and Trek teams.

We managed to spot the new drivetrain components while at the World Championships in Les Gets and got a reasonably close look at the BlackBox kit.

Redesigning the derailleur

SRAM Eagle AXS BlackBox rear derailleur and drivetrain
Plenty of BlackBox components were buzzing about the pits.
Alex Evans / Our Media

Although it doesn’t look as though SRAM has torn up the rear-derailleur rule book with its latest BlackBox kit, because it still uses a cage with two pulley wheels that connects to the parallelogram-style body with a knuckle, the eagle-eyed will spot some important changes.

Most obviously, the new BlackBox derailleur no longer mounts to a derailleur hanger. Instead, its b-bolt (the term used for the main mounting bolt) appears to attach directly to the frame or axle at the dropout.

The derailleur features ‘loops’ that attach it to the bike, essentially sandwiching the frame at its mounting point.

Although we we weren’t able to remove the back wheel on any of the bikes we saw with the BlackBox kit, the derailleur appears to only be compatible with bikes using SRAM’s Universal Derailleur Hanger (UDH).

UDH launched in 2019 and was sold as a solution to the many different derailleur hangers on the market, where if one, single system was used spares would be easier to come by and derailleur setup and alignment should be easier and more accurate.

If it’s correct to assume the new derailleur’s body mounts directly to the bike’s frame, and from what we saw at the World Champs this is the case, clearly more was at play when SRAM announced the UDH nearly four years ago.

SRAM Eagle AXS BlackBox rear derailleur and drivetrain
The lower pulley wheel’s spokes appear to be made from metal.
Our Media

Continuing that line of thought, it appears the UDH was a mere placeholder for the brand’s new derailleur design, where the derailleur’s b-bolt ‘loop’ replaces the hanger entirely.

However, if the new derailleur does replace the UDH, it’s good news for owners of bikes that use a UDH, where upgrading to the new system should be possible.

Looking from the rear of the bike, the derailleur’s profile is slimmer than current, hanger-mounted systems, sitting further inboard.

SRAM Eagle AXS BlackBox rear derailleur and drivetrain on Nino Schurter's Scott Spark at the Les Gets 2022 Mountain Bike World Championships
The bike Nino Schurter won the gold medal on at the 2022 XCO World Champs.
Scott Sports

By removing the hanger’s standard derailleur mounting position, everything looks further inboard than before, possibly reducing the chances of damage.

Arguably, the dual-sided ‘looped’ b-bolt mounting system looks more robust than current hanger-mounted derailleurs.

During the XCO race, gold medal finisher Nino Schurter put the new kit to the test as he crashed onto the bike’s driveside, skidding along the ground on one of the grassy turns that characterise the Les Gets course.

Jumping up unharmed, and bike undamaged, Schurter accelerated back to the front of the pack, winning the race.

The devil is in the details

SRAM Eagle AXS BlackBox rear derailleur and drivetrain
We couldn’t spot any high or low gear limit screws, or a b-tension adjustment screw on the derailleur.
Our Media

Looking closer, it seems other changes are afoot.

We couldn’t spot any adjustment screws on the derailleur. On all current derailleurs, high and low stop screws and b-tension adjusters are clearly visible, but SRAM’s new BlackBox derailleur seems to forgo additional adjustments.

Without those adjustment screws, it’s entirely feasible to speculate the new derailleur will require no tuning to work correctly, and it could be ready to ride as soon as it’s fitted.

The pulley wheels now look larger, too, where the lower wheel’s spokes appeared to be made from metal rather than plastic.

A whole drivetrain system

SRAM Eagle AXS BlackBox rear derailleur and drivetrain
The flat-topped chain’s design is taken from SRAM’s road bike components.
Our Media

It was hard to ignore the shiny teeth on the new-looking cassette the BlackBox derailleur was paired with.

Although it’s impossible to say whether the cassette’s teeth are coated with a long-last finish or not, it’s not the first time SRAM has used this type of finish. Currently, X01 and GX Eagle chainrings have silver-coloured teeth, similar to the new cassette’s finish.

Look closer still, and it appears the size difference between the biggest and second biggest cassette sprocket has decreased on this SRAM BlackBox drivetrain.

I couldn’t get close enough to count the number of teeth on the cassette’s sprockets, but it certainly looks as though the second biggest sprocket has grown, closing the gap to the Eagle bail-out gear.

The flat-topped chain’s shape looks to be taken from SRAM’s road bike Red eTap AXS groupsets, in a bid to further improve performance.

There are some small differences, however. The Blackbox chain’s outer plates have a hollow section, presumably in a bid to save weight, compared to the solid design of existing Red eTap AXS chains.

Multi-discipline BlackBox derailleurs

SRAM Eagle AXS BlackBox rear derailleur and drivetrain on Nino Schurter's Scott Spark at the Les Gets 2022 Mountain Bike World Championships
Nino Schurter rode the SRAM BlackBox rear derailleur to victory in the XCO race.
Cerveny / Scott Sports

Although the new BlackBox drivetrain was fitted to multiple cross-country race bikes for the XCO competition, we also spotted a Specialized Turbo Levo electric mountain bike sporting the new BlackBox kit, ridden by SRAM BlackBox Test Pilot Program rider Yannick Pontal.

This suggests the new BlackBox kit isn’t designed only for cross-country, but spans the disciplines. That said, I didn’t see a single downhill bike fitted with the brand’s Blackbox derailleur.

When is the new direct mount SRAM rear derailleur launching?

SRAM Eagle AXS BlackBox rear derailleur and drivetrain on Nino Schurter's Scott Spark at the Les Gets 2022 Mountain Bike World Championships
Nino crashed during his race run, but both body and bike remained unharmed.
Cerveny / Scott Sports

SRAM is clearly confident enough in its new derailleur’s reliability and performance that it’s willing to let 10-time World Championship winner Schurter ride it during the biggest mountain bike competition of the year.

Extrapolating information from that move, it would be a safe to assume the components are, at the very least, in the final prototyping stages, where any reliability and performance issues have been all-but ironed out.

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As soon as we get any more details or news on the new components, we’ll be sure to let you know.