SRAM continues to build on their Eagle Transmission mountain bike drivetrain system, announcing a new upgrade kit today that converts any Eagle 70 or 90 derailleur from mechanical to electronic. Eagle 70 and Eagle 90 drivetrains, the mechanical versions of the electronic AXS Transmission drivetrain, were released in March 2025. This new upgrade kit includes a derailleur body, wireless shifter pod, battery, and charger that promises to make the conversion quick and easy.
“Eagle 70 and 90 Transmission have been incredibly well received,” according to an email from SRAM. “We know SRAM riders appreciate the choice of a mechanical Transmission, but it’s awesome to know riders can easily upgrade their Eagle 70 or 90 Transmission-equipped bike to AXS Transmission with the GX Eagle AXS Upgrade Kit.”
Rebuildable design is modular, too
One of the key selling points for SRAM Eagle Transmission derailleurs, both mechanical and electronic, is that the derailleurs are highly rebuildable. Many pieces of the derailleur cage, including the pulley wheels, can be replaced. It’s this modular, lower portion of the Eagle 70 and 90 derailleur that can be attached to the body of the new GX Eagle AXS Transmission upgrade kit.
SRAM Eagle Transmission drivetrains require a specific T-type chain, cassette, and chainring, making the parts incompatible with non-Transmission drivetrains from SRAM. Eagle 70 and 90 owners already have all of these parts, so the only thing buyers need to upgrade to wireless electronic shifting is a new derailleur body and shifter.
Interestingly, the shifter shown in photos of the upgrade kit appears to be the AXS Rocker POD, rather than the AXS POD controller that ships with most complete GX Eagle Transmission groupsets. Riders seem to either love or hate the ergonomics of the newest Eagle AXS controllers, and this selection could suggest that riders prefer the Rocker POD over the two-button POD. In our testing, Singletracks has found the rubber button covers on the two-button POD are not easily replaceable if they are damaged or lost.
Buyers can use their existing T-type chain with the GX Eagle Transmission upgrade kit, but they’ll need a new PowerLock link, which SRAM helpfully includes in the kit. This may come as a surprise to some, but SRAM says PowerLock links are NOT officially re-usable.
“The PowerLock is designed for one-time use only. The PowerLock can only be removed with chain link pliers and must not be reused. Install a new PowerLock each time a new chain is installed. Reusing a PowerLock may result in a broken chain that could result in a crash.”
Mechanical. Electrical. Mechanical. Back to electrical.
Many mountain bikers were surprised (and stoked) in late March when SRAM announced a mechanical, non-electric version of their 12-speed AXS Transmission mountain bike drivetrain known as Eagle 90. With the addition of the upgrade kit, buyers can try both and swap between the two if they’re so inclined. However, it seems buyers are pretty split between electronic and mechanical shifting.
So, if SRAM has just released a mechanical version of this drivetrain, why are they now offering an electronic upgrade kit? The mechanical Transmission drivetrain is already proving to be a popular choice as a stock component spec on complete mountain bikes, especially for budget-sensitive mid-level builds. Due to the high performance and lower cost compared to the AXS electronic version, it is very likely we’ll continue to see this drivetrain offered on more stock bikes in the future. If you’re one of the many riders who has purchased (or will soon purchase) a complete mountain bike specced with a mechanical Transmission drivetrain and you’re e-curious, this upgrade kit is for you.
SRAM confirms that a “downgrade” kit will not be available for converting current GX Eagle Transmission AXS electronic derailleurs to mechanical derailleurs. For those who don’t already own a T-type drivetrain, and would like to have the option of either mechanical or electronic shifting, you’ll want to purchase an Eagle 70 or 90 Transmission groupset along with the GX AXS upgrade kit.
The GX Eagle AXS Transmission upgrade kit is priced at $550. A dedicated GX Eagle Transmission AXS derailleur costs $400, and an AXS POD Controller Rocker is $150, so buyers of the upgrade kit are basically getting a free battery and charger, plus a QuickLock.
0 Comments