Need a New SRAM Transmission?

Written by Isaac Boyden, on March 21, 2023

What Is SRAM Transmission? 

In late summer 2022, the mystery groupset was first spotted on Nino Schurter's Scott Spark RC at his winning performance at the UCI World Championships. Once spotted, the rumor mill started churning. What is it? When will it be available? How will it be different from XX1 AXS? Well, today we found out. Here are the details.

This is an entirely new groupset called Transmission and it is completely separate from Eagle. Eagle will still be supported and made, so this is an additional range of groupsets. The only backwards compatible parts are the batteries and shifters, all other components are not compatible. Everything for Transmission will be labeled as T-Type on the side (i.e. chainrings saying “T-Type chain only” on them) But why? What's the whole point of this new line?

With the introduction of SRAM UDH (Universal Derailleur Hanger), SRAM now controls the frame spacing in the rear, the cassette, the chain, and the derailleur. With every variable around the axle being a controlled variable, SRAM Transmission will bolt directly to the frame, forgoing a hanger. This means there is no need for a high or low limit screw and no B-tension screw. Once you get it set up, it just works. Needing no adjustment, the full system has zero tolerance, leading to a perfectly shifting system according to SRAM. The hangerless interface is called “Full Mount”. This also causes the entire system to be stiffer and stronger. Currently this system is compatible on 600+ bike models that support UDH. 

Built With Performance Intent 

Similar X-sync technology as seen on the Eagle chainrings is used to provide cassette mapping. With cassette mapping and a flat top chain, the Transmission groupset will shift perfectly every time (according to SRAM) regardless of power output. SRAM claims the harder you pedal, the better it shifts which is super cool and fairly new. They say even in a 1100+ watt sprint or on an ebike, the system will still shift super smooth. Under power and constant load and regardless of pedal stroke position, shifting performance and precision remain the same. 

There are bound to be questions and concerns about the lack of a rear derailleur hanger and how that impacts the system's durability to crashes. If you did hit the rear derailleur on Transmission, the B-knuckle, the skid plate, and pulley cages are all replaceable small parts as opposed to normal Eagle AXS where you would need to replace the whole rear derailleur. They also claim the new cassette and chains are the strongest they have ever made, doubling the life expectancy. The XX and XX SL levels also have what SRAM calls the Magic Pulley, which should unjam itself if (when) filled with muck. The new system also uses a two-piece cassette pinned together.

Levels And Configuration 

There are three levels for the new system, called XX SL, XX, and X0. XX SL and XX are equivalent in the line but meant for different purposes. XX is the top-end trail and enduro-oriented groupset. XX SL is the top-end for XC riders sacrificing a little durability to save on weight. Finally, X0(at a lower price point), can cover the gambit of mountain disciplines with a relatively modest weight penalty. *Update: See info below for new GX AXS Transmission!

For all three groups, the controllers are ambidextrous and fully symmetrical to be flipped to run on whatever side of the bar you prefer. Called AXS pods, they clamp inboard or outboard giving much more adjustability to refine how you would like to ergonomically set them up. The groups are all power meter compatible featuring Sram’s eight-bolt chainring mounting interface. With the release of Transmission, SRAM also introduced a less expensive spindle based power meter. The XX and X0 chainrings have built-in bash guards as options. 

Sram did make some small changes to the system to ensure durability and performance. The biggest thing they changed is the position of the battery. Instead of being attached to the back of the derailleur, now the battery slots in between the two mounting arms that attach the derailleur to the frame. This ensures a clean look and a sleek, slightly smaller rear derailleur. Sram increased the size of the AXS Pod buttons as well as making the tolerance a little lower for the button press, which increases the ease of use of the system. Overall the GX Transmission system is extremely similar to the other Transmission lines, with their cassettes, chains, cranksets, and derailleurs all being cross compatible with one another.


There is a lot of buzz and excitement and Contender is definitely eager to put Transmission through its paces. Like most new products, we like to hold judgment until the rubber hits the road (or trail in this case). SRAM asserts a lot of performance features with this launch. We look forward to getting out on some bikes with the new Transmission drivetrain and seeing if it lives-up to the hype. 

GX TRANSMISSION - Added July 12, 2023

Now, three months after we saw the X0 and XX Transmission kits released, Sram has followed up with a GX Transmission variation. Like the current GX AXS, GX Transmission is aimed at being a more budget friendly alternative for electronic shifting on your mountain bike. SRAM has preserved most of the technology offered in the higher end options, with the exception of the Magic Pulley. The derailleur will be fully maintainable with Sram’s replacement part options, and some of their replacement parts are cross compatible between the now three tiers of derailleurs. You will be able to add the XX or X0 cage to the GX Derailleur to get the Magic Pulley on your bike. 


  • Hey Brian! 2022 and 2023 Spark 970s will work with a X0 Transmission yes! Pre 2022 970 Sparks will not.

    Isaac Boyden on

  • I have a Scott Spark 970. Can the SRAM XO Eagle Transmission group set be fitted to this model ?

    Brian Culver on

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