Smooth under pressure

Illustration by Emma Steele


SRAM says its new Eagle Transmission drivetrain is designed to change the way we experience riding. They claim to have learned from their athletes and test team to create a system that erases mistakes, simplifies setup and extends the system’s lifespan. The new Eagle Transmission drivetrain components are offered in three levels: XXSL, XX and X0.


Let’s start by saying that SRAM’s new Transmission drivetrain sets the bar in drivetrain shifting smoothness, particularly under power. Months of testing with more than one drivetrain revealed no issues or weak links, however, we got off to a rough start with our Transmission drivetrain and for a surprising reason. Our test group came pre-installed on a Giant Trance X from SRAM. Right off the bat it shifted fine in the stand but poorly on the trail. Our online first impression story was lukewarm to say the least.

A crossthreaded cassette got our test off to a rough start.



A few phone calls with SRAM and head scratching on both our parts lead to a whole new drivetrain overnighted to us. Swapping one component at a time to trace down the culprit revealed that the cassette was cross threaded and not fully engaged on the driver body causing it to deflect under a load. A new cassette properly installed made everything suddenly work perfectly. Our takeaway: make sure the cassette is fully and evenly engaged on the driver’s spines before tightening – even a SRAM tech made a mistake on this step.



All the wrenching and troubleshooting highlighted just how easy this new drivetrain is to set up. It all starts by looking up your bike on SRAM’s app or online setup guide and entering information such as frame size, adjustable geometry position and chainring size. Once entered, it gives you one of the two available derailleur setup key positions, chain length and your setup cog – the cog (usually 21 or 24 tooth) that you put the derailleur and chain in to set the derailleur’s position. To do so, you simply pull back gently on the derailleur’s cage and tighten the main mounting bolt to 35 Nm. You need to verify that the knurled ring line is aligned correctly with the lie on the derailleur. These steps only need to be repeated if you change the frame’s adjustable geometry, chainring size or position of a lower idler pulley. From there you just use the shifter’s micro-adjust feature to fine tune the shifting.

That’s it, you’re done. Between the lack of wires or cables and the far more simplified overall setup, it takes a fraction of the time to install and adjust the Eagle Transmission drivetrain compared to all others.


With everything working properly, shifting is incredibly smooth, particularly under power just like SRAM claims. SRAM drivetrains always took a back seat to Shimano’s in terms of shifting smoothness but now it’s on par with or even better than Hyperglide under pedaling load. It’s almost as if it shifts better the harder you pedal – it’s pretty incredible. And it doesn’t matter if you’re moving up or down the cassette, both are equally smooth. Test riders who had trained themselves to let up on pedal loads while shifting had to retraining themselves to stay in it. SRAM warned that battery consumption might be higher in it’s FAQs but it seemed on par with old AXS. And that’s even with us shifting sometimes during a ride just to feel the smoothness of the shift.

We’ve all seen the videos and photos of people standing on the Transmission derailleur but what happens when you’re actually out on the trail and really hit something? Not much it seems. We smacked rocks big enough that we thought the derailleur was done for with nothing more than a few scratches as a result. Super deep rain ruts had us grinding derailleurs on the sides over dirt and embedded rocks without skipping a beat. We are impressed and can’t say we miss the traditional derailleur hanger.



Test riders had mixed feelings about the new pod shifters. Some liked the new button style over the old pseudo-lever AXS shifter while others didn’t. Those who did liked the position of the pod and the more tactile click of the buttons. Some wanted more position flexibility and a lighter press of the button. They didn’t hate the shifter but just wanted something slightly different. The good news for them is that the old AXS paddle style shifter is compatible with Transmission so there is probably a solution for anyone.


The worst thing about Eagle Transmission is the slower shift speed. Each shift is timed to utilize shift ramps in the cassette instead of just forcing it into the next gear so there’s a slight delay to each gear change. It’s not noticeable making one or two shifts but it really becomes apparent when you are faced with a steep climb out of a turn or somewhere that takes you by surprise because you can’t dump gears quickly. We had to anticipate them and shift early or we were left walking. Otherwise, there’s not much bad to say about Eagle Transmission. It’s heavier and more expensive than AXS but we feel the shifting performance and ease of setup is well worth it.


At the heart of the Eagle Transmission system is the all-new T-Type rear derailleur design with a hangerless Full Mount interface. Any bike with a UHD derailleur hanger is compatible with this new system—in other words, pretty much all new bikes. According to SRAM there are 210 UDH compatible frames and counting. There is a frame compatibility list on SRAM’s website.

SRAM says that using this universal constant, it removes all variances and allows for perfect shifting by creating a single holistic system. Gone are all adjustment screws – there are no B-tension, high or low limit adjustment screws because they are no longer needed. The hangerless interface eliminates tolerances between the derailleur and cassette for what SRAM says is a much more reliable shifting performance.

At first glance from behind the bike, the T-Type derailleur cage looks bent because it’s designed to follow a yaw angle that aligns the upper pulley with the 10-tooth and 52-tooth cogs as it moves across the span. It is also designed to keep the lower pulley at the optimum angle with the front chainring to reduce wear. The lower pulley is called the Magic Pulley because it can rotate even when the wheel becomes jammed preventing catastrophic damage.

Another benefit to the new derailleur design is that it’s rebuildable. According to SRAM, the mounting bolt hardware outer parallelogram link, inline cage, damper assembly, and Magic Wheel are all replaceable. Price ranges from $650 for the XXSL to $550 for the XO version. Our XX SL derailleur weighs 436 grams with a battery.


New pod-style shift controllers are now ambidextrous – they can be mounted on either side of the bar. This allows for left or right-side mounting which allows you to also mount an AXS Reverb remote on the right side if you want. An all-new Bridge Clamp allows for placement of the pods inboard or outboard of the brake lever clamps and they have a greater adjustment range compared to the previous Matchmaker X clamp too. According to SRAM, the POD electronic controllers can be used with Eagle Transmission, as can any other two-button SRAM AXS electronic controller. Eagle Transmission is also compatible with eTap AXS Wireless Blips. The Ultimate version of this shifter costs $200 while the standard one runs $150. The Ultimate shifter with discrete clamp weighs just 50 grams.


The new T-Type cassette is designed to perform under pressure. According to SRAM, the harder you pedal, the smoother it shifts. To create continuous chain engagement and uninterrupted power transfer, SRAM claims the derailleur’s firmware references a uniquely timed shift sequence to align with the releasing/receiving cogs – engaging chain rollers on the desired cassette teeth when a shift is made. In other words, SRAM’s X-Sync technology on the cassette combined with retimed shift routes offers improved shift quality under a load. Pricing ranges from $600 for the XS-1299 to $400 for the XG-1295. An XX Eagle Transmission cassette weighs 380 grams on our scales.


An all-new flat-top style chain is designed to maximize shifting performance and robustness while adding style points at the same time. The XXSL version features outer plate cut-outs to save weight and is not eMTB approved. The hard chrome finished XX version is SRAM’s strongest chain ever made. And so is the X0 version and because it has solid pins, it’s also eMTB approved. These chains are not inexpensive. An XX SL runs $150 while the XO model costs $100. An uncut new XX SL chain hit our scales at 213 grams with connecting link.


SRAM is offering a wide range of cranks to go with this drivetrain ranging from the ultra-lightweight carbon-armed XX SL Eagle model to the more robust aluminum-armed X0 version with removable bash guards at the top and bottom of the chainring. There is also a power meter crankset with a very unique thread-on style chainring mounting system as well as more standard-issue Quarq models with the power meter in the spindle. SRAM also offers eMTB-specific carbon fiber and aluminum crank arms for Brose and Bosch motors. Pricing ranges from $1,050 for the Powermeter XX SL crank to $150 for XO ISIS eMTB aluminum crank arms.


SRAM offers an AXS app that helps not just with setup and adjustment, but offers videos and can guide you on bike-specific chain length setups and other setup information.


  • Smooth shifts under power
  • Ultra-easy setup


  • Slower shifts




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