Electronic components have become the norm on eMTBs. To date, wireless components remain a rarity, however. That’s set to change with the new SRAM Eagle AXS drivetrain and the RockShox Reverb AXS. Laying the foundation for a new type of connected bike.

Introducing two new wireless components with SRAMs Eagle AXS drivetrain and RockShox’s Reverb AXS dropper post

SRAM AXS – what is it?

AXS is a new standard for data transmission specially developed by SRAM. It has similarities to the technology used in the remote key of a car but requires less power and works without any noticeable delay. When you press the button on the remote, the valve on the dropper opens and remains open only as long as you keep the button pressed. It’s similar with the drivetrain, one click and the derailleur shifts gears instantly. The shifter uses a 2032-button cell battery which is claimed to last two years. Unfortunately, the SRAM AXS derailleur and the Reverb dropper don’t get their power from the eMTB battery, each relying on their own power source. However, the battery is identical for both components and can be swapped back and forth as needed. On the derailleur, the battery lasts about 20 h, while it should last about twice as long on the Reverb dropper. AXS is designed in such a way that all SRAM AXS components can communicate with each other, so you could even actuate the Reverb with one of SRAMs eTap brifters. SRAM has developed their own AXS app which you can use to install firmware updates, configure the assigned function of the buttons or to check the battery level. The latter can also be checked directly on the derailleur or dropper post itself.

Shifter and dropper cables are now a relic of the past. Wireless connectivity makes for a much tidier cockpit, especially on an eMTB.
AXS is the data transmission standard developed by SRAM, via which the individual components communicate wirelessly
Pressing the button on the remote opens the valve on the dropper post. It’s extremely fast and super precise, popping up without a noticeable delay.
Both the derailleur and the dropper post are powered by a small battery. A full charge takes about one hour and will last about 20 hours on the derailleur and 40 hours on the dropper post.

RockShox Reverb AXS in detail

The basic principle of the proven RockShox Reverb is the same. The seat post still has a hydraulic interior in which the oil is pressurised via an IFP (Internal Floating Piston). However, the inner workings have been reworked and the friction reduced, requiring less force to drop the saddle. Being wireless there’s no need for a cable exiting the bottom of the post and RockShox has the space to install their so-called Vent-Valve. This allows you to easily purge the dropper should air get trapped inside with the oil, resulting in a spongy feeling dropper. The process can easily be carried out in about 30 seconds, even if you have zero technical experience or know-how. The seat clamp has also been completely redesigned and now enables a much faster and easier adjustment of the saddle. But, of course, the biggest innovation is the absence of a cable to actuate the dropper. The command is transmitted wirelessly from the handlebar using SRAM’s new AXS technology.

Diameter
30,9 mm | 31,6 mm | 34,9 mm
Travel
100 mm | 125 mm | 150 mm | 170 mm
Length
340 mm | 390 mm | 440 mm | 480 mm
Battery
Seatpost: SRAM battery| Controller: CR2032
Compability
Zero offset | 7 mm round rails | 7 x 9 mm oval rails | Matchmaker or own clamp
Price
€ 800
Avaiability
End of march 2019

Besides the electronics that have been added to the Reverb AXS, the mechanical components have been fundamentally revised.
A highlight is the new seat clamp, with which you can adjust the tilt of the saddle quickly and easily.
With the new Vent-Valve, purging the dropper post is quick and easy
Shown here, the valve, the electronics and the servo motor of the new Reverb. All three parts are contained in the newly designed clamp.

SRAM Eagle AXS in detail

The new wireless SRAM Eagle AXS is based on their well-known and proven Eagle technology, slotting in right at the top of the American brand’s product range. The electronic drivetrain is compatible with existing Eagle components such as the chain, cassette and crankset. At the heart of the new groupset is the AXS data transmission standard via which the individual components communicate with each other, specially developed by SRAM. The communication is quick and very energy efficient. The derailleur also has a Bluetooth and ANT + module, allowing it to communicate with other external devices. Using the AXS app, you can customise the drivetrain to your preferences, perform a firmware update or set yourself a service reminder. However, you don’t need the app to use the drivetrain.

Battery
Rear derailleur: SRAM battery | Controller: CR2032
Gear Range
500% 10-50
Configuration
SRAM App
Price
XX1 € 2,100 | XO1 € 2,000
Availability
End of March 2019

The SRAM AXS derailleur and shifter are eMTB compatible
With the newly developed shifter, your thumb rests on a large paddle. Alternatively, you can also shift either up or down by pulling with your index finger.

The new wireless SRAM Eagle AXS is based on their well-known and proven Eagle technology, slotting in right at the top of the American brand’s product range. The electronic drivetrain is compatible with existing Eagle components such as the chain, cassette and crankset. At the heart of the new groupset is the AXS data transmission standard via which the individual components communicate with each other, specially developed by SRAM. The communication is quick and very energy efficient. The derailleur also has a Bluetooth and ANT + module, allowing it to communicate with other external devices. Using the AXS app, you can customise the drivetrain to your preferences, perform a firmware update or set yourself a service reminder. However, you don’t need the app to use the drive train.

Using the specially developed app, you can customise the assigned function of the individual buttons to your suit preferences, among other things

The SRAM Eagle AXS and Reverb AXS on the trail

We’ve already had the exclusive opportunity to test SRAM’s new AXS components – but not on an eMTB. You’ll find a detailed review of the SRAM Eagle AXS drivetrain and the RockShox Reverb AXS on our sister site ENDURO. Since the use of a dropper seat post on an eMTB doesn’t differ from non-electric mountain bikes, there are no restrictions to consider here. That’s not the case with the drivetrain, however.

So far we have only been able to test the new AXS components on a non-electric mountain bike. However, the function of the Reverb AXS is identical.

The SRAM Eagle AXS drivetrain on an eMTB

According to SRAM, the wireless Eagle AXS rear derailleur and shifter are eMTB compatible. However, the new X01 and XX1 Eagle cassettes are intended exclusively for non-electric mountain bikes. SRAM recommends eMTBers continue using the NX cassette with the corresponding chainring. However, since SRAM will only be offering the groupset as a complete package for € 2,000 (X01) or € 2,100 (XX1) with the cassette, chain, bottom bracket, etc., eMTBers will have to be patient for now. The individual components should become available at some point in the future. We are confident that we’ll also be seeing complete bikes specced with AXS components.

 The Eagle AXS impressed with extremely fast and extremely precise shifting on a regular mountain bike. How it performs on an eMTB, we will find out for you soon.

Not on an eMTB! The beautiful rainbow cassette is designed only for non-electric mountain bikes. When used on an eMTB, the electronic drivetrain should be combined with an NX cassette.
Helmet Specialized Ambush | Jersey iXS VIBE 8.1 | Shorts iXS ASPER SHORTS | Shoes ION Rascal

Our opinion on the new SRAM Eagle AXS and the RockShox Reverb AXS

Unfortunately, we haven’t yet been able to test the new components on an eMTB. Since the function of the Reverb is the same on all mountain-bikes, however, we can already draw a first conclusion here: the RockShox Reverb AXS is extremely fast, super precise and delighted our testers with smart details like the practical adjustment of the seat clamp and the new Vent-Valve. It’s the best seat post currently on the market, bar-none, but at € 800, it’s no bargain.

Thumbs up for the Reverb AXS – we happily recommend it for your eMTB!

It remains to be seen how the Eagle AXS will cope with the strains of eMTBing. However, the future potential of connected components is huge. Not only is the installation a lot quicker and easier, but the communication between individual components opens up unthought of new possibilities. Imagine a smart bike where the suspension automatically adjusts to suit the terrain via data collected by a sensor in the rear derailleur or where the derailleur automatically aligns itself. Sounds like pie in the sky, but so did eMTBs until a few years ago.

For more information head to sram.com

You’ll find a detailed review of the SRAM Eagle AXS drivetrain and the RockShox Reverb AXS on our sister site ENDURO.

Words: Christoph Bayer Photos: Christoph Bayer, Margus Riga

About the author

Christoph Bayer

Christoph loves to be kept on his toes – both on the bike and in his role for the E-MOUNTAINBIKE Magazine. He’s known as the guy in charge of the magazine and masquerades as both its editor and photographer. You’ll usually find him tearing up the mountains on his bike, soaking up the flow or tackling technical, narrow trails.