SRAM Eagle AXS 2021, we test the most advanced MTB groupset of the moment

Mountain bike 30/01/21 17:33 Migue A.

First we heard about it through rumours, as well as some stolen images of the first prototypes that came to light, then we saw several test versions in competition, and finally the SRAM XX1 Eagle AXS arrived on the market in 2019 as the first electronic and wireless 12-speed groupset. In 2021 the SRAM XX1 Eagle AXS was updated with some important new features, such as the 10-52 cassette or the new shifter. We were able to test it for quite a few kilometres. Here we tell you all about it.

SRAM XX1 Eagle AXS 2021, a very unique drivetrain 

As we said, SRAM updated its drivetrains for 2021 and the XX1 Eagle AXS electronic rear derailleur benefited from important new features such as the 10-52 cassette or the SRAM Rocker shifter. But although the SRAM AXS has been on the market for three years now, the truth is that for many it is still a novelty and even among some enthusiasts there are still questions such as: is electronic shifting for mountain bikes reliable? is it fragile? does it fail? So let's first try to clarify these doubts.

Is the SRAM XX1 Eagle AXS reliable?

It is true that in the common imagination electronic devices are associated with fragile components and precisely the rear derailleur of a mountain bike is perhaps one of the parts most exposed to shocks, bumps, mud, water, etc. But if we start with this section, we can only tell you that AXS groupsets are as robust and reliable as any of the mechanical versions of SRAM or any other brand. With an IP69K degree of protection, the XX1 Eagle AXS rear derailleur is protected against water (it can operate submerged in a river for example), dust, mud, snow, etc. It's also resistant to pressurized water, so you'll have to make another excuse if you don't keep your bike clean.

In our tests we have not experienced any failures, but beyond our experience, in 2020 we saw how Emily Batty crossed Iceland across icy torrents for a week without her AXS group being harmed, or how Jordan Saarrou or Pauline Ferrand-Prevot themselves won the 2020 rainbow jerseys on a completely muddy course that tested the toughest drivetrains.

So we can safely say that the SRAM XX1 Eagle AXS is a very reliable and precise groupset. And here we could add that, in addition to weather protection, the rear derailleur has two impact protection systems: its own design and the Overload Clutch function.

It may seem a contradiction to say that the design is an element of protection, and those who have mounted SRAM derailleurs will already know that one of their particularities is that they stand out more from the frame than Shimano, but in this case the AXS version, although it is also "detached" from the frame, is more compact than the mechanical XX1, wraps the cassette better, and its cage is shorter to have 10mm more clearance with the ground. This design provides passive protection and thanks to the Overload Clutch system, if the derailleur receives an impact, the motor disengages the gearbox, giving the derailleur the freedom to absorb the shock.

Is this precise?

Returning to the subject of precision, we can talk about the new SRAM Rocker paddle shifter. It is not exactly a new button but a small update that transforms the angles of the first version to offer a more ergonomic and comfortable experience, with a larger surface area

We can say that the SRAM XX1 Eagle AXS paddle is the gateway to a new way of shifting in which every time you click it, only one thing can happen, that you raise or lower the sprocket precisely and accurately, whatever the situation. This feeling of shifting security justifies the high price of this groupset. 

From the App you can configure the operation of the paddle so that by leaving it pressed down, it raises or lowers more than one sprocket at a time, this gesture can be done with the thumb pushing or with the index finger as a trigger, but the truth is that we have found it faster to make the changes one at a time than with long presses. The sensitivity of the push-switching is simply outstanding. Even with cold numb hands, shifting is no longer a problem.

To try to describe the shifting experience with the SRAM XX1 Eagle AXS, we could say that in situations of high stress, such as hard climbs, we feel that the AXS has a harder shifting experience than, for example, the Shimano XTR.

Installation and adjustments for even the most clumsy "mechanics"

Another great thing about the AXS system is the ease of installation and adjustment it offers. If we are only installing the rear derailleur and push button (the upgrade kit) most of the time spent and the curses will be taken away by having to remove the cables and casings from our previous groupset.

For the AXS, once the derailleur is anchored to the frame and the pushbutton to the lever using the Matchmaker system, or to the handlebar with the included adapter. We can forget about using any more tools. Matching the pushbutton and derailleur is a simple task with the included button and LED system, and shifting adjustment is made easy using the pushbutton itself and the new B-GAP gauge.

Autonomy of the SRAM XX1 Eagle AXS electronic components

Once the questions about reliability and precision have been successfully answered, the next one, when talking about an electronic component, will probably be about autonomy. In this case the XX1 Eagle AXS derailleur has a claimed range of 20 hours, but in all our tests we've exceeded that threshold even in winter, so we'd say 25 hours would be a fair prediction in the absence of knowing how the battery behaves over the years.

The rear derailleur has a LED light that turns red to warn you to think about charging the battery. We haven't mentioned it so far, but the battery is removable and can be taken out very easily without the need for any tools. The push button also features a LED light to let you know when you need to change the classic CR2032 battery that powers it. Although in this case you can probably forget about it for at least a year and a half, maybe more. And maybe that's its biggest drawback, you could forget about it and one day get a surprise, so a good idea is to add one of those little button batteries next to the multitool that you never forget at home when you're out riding.

The Eagle 520% cassette - was it necessary?

The 10-52 cassette is undoubtedly the most important new feature of the SRAM XX1 Eagle AXS in 2021, but it has also been criticised for being too big a leap between the two largest sprockets.

The first question we could ask ourselves is why SRAM has introduced this cassette in its catalogue and the answer that convinces us the most is: because it can. Apart from the benefits to the rider, this 10-52 cassette is a technical showcase for SRAM in the face of its competitors, as is its entire AXS groupset. SRAM was the first to introduce the effective and functional 12-speed to mountain biking and with this 10-52 it proves that it is capable of getting the most out of it.

In fact this cassette came about during the development of the SRAM AXS itself, when the engineers realised that they could stretch the rollout of the cassette a little further with this rear derailleur. That's why if you already had a SRAM XX1 Eagle AXS you can mount the 10-52 cassette without having to upgrade the rear derailleur, something that cannot be said for the first mechanical version of the XX1.

In our experience riding with the Eagle 10-52 cassette we can say that the jump from the 42 to the 52 sprocket does not really feel natural and takes some time to get used to it, but it is also true that it is capable of getting you out of tight spots in which the only thing left for the physicist to do is to look for help in the mechanics.

For multi-purpose use we still stick with the 10-50, but we also think the 10-52 is the perfect cassette for any XCO race.

Do you need the SRAM XX1 Eagle AXS on your mountain bike? Is it too expensive?

After several months with the SRAM XX1 Eagle AXS 2021 we have to confess that we wouldn't want to go back to a cable shifter. But we will have to develop this statement a little better because we are talking about a groupset that in its basic upgrade pack (rear derailleur, shifter and battery) has a price of €1050, although it can already be found in some shops for around €800.

As we've already realised, the XX1 Eagle AXS offers a unique shifting experience where hesitation and faults disappear, as long as you remember to check and charge the batteries of course, and that's something no mechanical groupset can currently say. Although it is also true that any of the SRAM or Shimano cable versions offer excellent performance for 90% of users, including professionals.

In this aspect we have to remember that the XX1 Eagle AXS is the most exclusive groupset in the SRAM catalogue and the most technologically advanced at the moment. Whether the benefits it provides correspond to its price is something that everyone will have to evaluate individually, although there is still an important point that we have not commented on, the aesthetics.

Electronics have made it possible to do away with the messy world of cables and casings, but have also achieved something that for many nowadays is more important than the performance itself: an aesthetically more elegant mountain bike in which the lines of the frame are not obscured by the cables of the drivetrain.

In short, the SRAM XX1 Eagle AXS is the most reliable and precise groupset we've tested so far and the only one that lets you show off your mountain bike in the coolest possible way. In return you'll have to pay a lot for it and don't forget to charge the batteries.

SRAM XX1 Eagle AXS 2021: price, weight and specifications 

XX1 Eagle AXS Derailleur

  • XC focus and trail ready
  • System is completely water and dust proof to IP69K
  • Impact protection with a double clutch system
  • Exchangeable battery
  • Carbon cage with compact design for protection from lower impacts 
  • Weight: 352g + 25g (battery)
  • Price: 750€ without battery
  • Price battery pack (1 battery + charger) 71€.


Eagle AXS Rocker Paddle

  • Available as a complete controller or standalone paddle option for all Eagle AXS controllers
  • Customize in-board and outboard shift options
  • AXS enabled components are able to be programmed and personalized using the SRAM AXS App.
  • Right handlebar position
  • Matchmaker system for direct installation on SRAM levers or stand-alone installation
  • CR2032 battery
  • AXS controller: 82,5g
  • Rocker weight: 13,9g
  • Price: 200€ + 20€ (rocker)


XX1 Eagle DUB SL Crankset

  • DUB technology delivers the lightest, stiffest and strongest crankset available
  • SRAM CARBON TUNED crank technology provides extreme stiffness and light weight
  • Crank arm length (165,170 o 175mm)
  • Chainring (30,32,34,36 o 38T)
  • Weight of the set with 175 crankset and 32t chainring: 446g
  • Price: 571€


XG-1299 EAGLE Cassette

  • Expanded gear range of 520%
  • 12v 10-52t, 10,12,14,16,18,21,24,28,32,36,42,52
  • X-Dome technology for better dirt evacuation
  • Available in black, gold, rainbow and copper colours
  • Weight: 381g
  • Price: 457€
  • Only compatible with AXS groupsets or the latest mechanical versions adapted for the 10-52.


SRAM XX1 Eagle Chain

  • Groundbreaking new chain design and technology
  • All-new Eagle Power Lock chain connector with FLOWLINK technology provides better chain-guiding and increased longevity
  • Colours: black, gold, rainbow and copper
  • Weight: 261g
  • Price: 90€

Although we have given you the price of each component, you can buy the complete SRAM XX1 Eagle AXS groupset (rear derailleur, battery with charger, paddle, cassette, crankset and chain for 2100€, but you can already find online offers with savings of up to 700€.

SRAM XX1 Eagles AXS 




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SRAM Eagle AXS 2021, ponemos a prueba el grupo de MTB más avanzado del momento