Launched as an upgrade kit for existing Eagle drivetrains, the new SRAM GX AXS looks like an alluring entry point to electronic gears. Today SRAM launches the all new GX version of the AXS drivetrain bringing electronic shifting to a lower price point. 

When the first AXS groupset was launched it was built around the familiar and proven technology eTap technology from the road bike market. It features similar motor technology and the same easily removable batteries but with an all-new Trigger Shifter to operate the mech on mountain bikes.

 

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2021 SRAM GX AXS drivetrain-16 (Image Credit: Rachael Wight)

Now the trickle-down tech has come to the next groupset in the lineup, GX Eagle. SRAM says that they want this kit of a mech, shifter and battery to be seen as an upgrade for any existing Eagle drivetrains. Meaning that if you currently have an Eagle set up you can buy a mech and shifter for £554 and upgrade.

2021 SRAM GX AXS drivetrain fitted-13.jpg
2021 SRAM GX AXS drivetrain fitted-13 (Image Credit: Rachael Wight)

SRAM AXS GX Derailleur 

The derailleur is specifically designed to be driven by motors rather than actuated by cables. It has the same one-way clutch mechanism as a normal mechanical mech with the cage lock too, but it’s now joined by the Overload Clutch which protects the internal gearbox motor from damage in the event of a crash. In the event of an impact, the motor gearbox disengages, giving the derailleur freedom to move, and instantly returns back to its position for a seamless experience for the rider.

The other difference is the inclusion of the motor and of course the battery, plus the fact that this one connects wirelessly to the new shifter up on your bars. 

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2021 SRAM GX AXS drivetrain-7 (Image Credit: Rachael Wight)

 

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2021 SRAM GX AXS drivetrain fitted-4 (Image Credit: Rachael Wight)

It’s compatible with both the 10-50T cassettes and also the newer, larger range GX 10-52T ones. Trim is the term used for aligning the mech and that is set at installation, there are about 30 micro positions the mech can be set at within each of the 12 gear clicks. The mech is also completely waterproof so it should survive the cruddy UK winter conditions. 

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2021 SRAM GX AXS drivetrain-2 (Image Credit: Rachael Wight)

 

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2021 SRAM GX AXS drivetrain-8 (Image Credit: Rachael Wight)

So what are the differences between the GX mech and the high-end ones?  Just the pulley bearings and the cage material. These differences making the mech heavier at 465g, including the battery. A mechanical GX mech is 300g, making the GX AXS mech a little bit heavier hanging off the back of the bike, where you don’t really want extra weight. It’s something to bear in mind for those looking to drop weight. 465g is also a fair bit more than the 350g XX1 AXS mech but it’s also a fair chunk cheaper than XX1 which’ll cost you £660! Here’s that in a table so you can easily compare the differences. 

 

GX AXS

XX1 AXS

GX mechanical

Weight

465g

350g

300g

Cost

£352

£660

£110

 

2021 SRAM GX AXS drivetrain fitted-3.jpg
2021 SRAM GX AXS drivetrain fitted-3 (Image Credit: Rachael Wight)

 

Shifter

The shifter developed for AXS is pretty much the same across the board in terms of SRAM electronic mountain bike drivetrains. The big and obvious difference from other mechanical shifters is the lack of cable running out from the shifter and into your frame, it’s super neat.

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2021 SRAM GX AXS drivetrain-9 (Image Credit: Rachael Wight)

The  Eagle AXS Trigger Shifter is basically a rocker paddle; slide your thumb up or down to shift to a different gear. What each button does can be totally configured through the new AXS app, plus you can set up double or single shifting here too. There’s a neat trick up its sleeve though, SRAM has added a “Secret Sprint” paddle on the front-side of the controller that you can operate via your index knuckle when you’re out of the saddle and sprinting, whether it’s in an XC race or an enduro.

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2021 SRAM GX AXS drivetrain fitted-6 (Image Credit: Rachael Wight)

It weighs 80g’s, it’s compatible with Matchmaker X gear, it’ll pair with any other AXS mech and it too is completely dust and waterproof.

 

Batteries

Sold separately from the mech the battery adds just 25g and is removable, just like on the more expensive gear, and provides a claimed 20-hours of riding time. Of course, there are many variables that will dictate the actual runtime. There are two included here, plus a small charger.

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2021 SRAM GX AXS drivetrain-18 (Image Credit: Rachael Wight)

Also sold separately is a battery cover which you need to remove and replace on changing out the battery.  SRAM says you’ll get 40/50 hours on a single charge, I’ve had mine fitted a little while not but realistically only put in about 15 hours of ride time, safe to say I’m still on the same battery.

 
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2021 SRAM GX AXS drivetrain-19 (Image Credit: Rachael Wight)
The upgrade kit is £554, in there you get a mech, shifter, battery, battery cover and a chain gap tool. If you buy separately the mech is £342, the shifter £139 and the batteries  at £50 each.

Think that sounds expensive? Well, it is pricey compared to simply buying yourself a new mechanical GX mech at £110 and a new shifter at £36, plus a tenner max for new inner and outer should they need replacing.
 

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2021 SRAM GX AXS drivetrain-15 (Image Credit: Rachael Wight)
In return for your five hundred quid spend though you get a drivetrain that is quick to install, reliable and tunable. It clears up a cable at the front of you bike making for a cleaner looking set of handlebars. Of course you also have to factor in a little charging faff but I’m sure like charging your phone it’ll soon become second nature.

 

First Ride

In a real world sense the AXS kit was easy to fit, not having the cable to fiddle with simplifies the process massively. If you are used to using a regular shifter then the new action of this one takes a little bit of getting used too. I was advised to use a thumb and a kind of rolling action to operate it but realistically my thumb is a little small for that and I find myself moving from top to bottom of the paddle to shift up and down.

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2021 SRAM GX AXS drivetrain fitted-9 (Image Credit: Rachael Wight)

The mech at the rear does look like a bit of a behemoth, but you soon get used to the look  of the larger mech is become normal. The extra weight ins’t immediately discernible either, especially not on this bike which wasn’t exactly built to be light. The upper heavier potion of the mech is up in the battery/motor which is stable and secure on the hanger rather than hanging lower and moving around over rough stuff like the cage does.

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2021 SRAM GX AXS drivetrain fitted-12 (Image Credit: Rachael Wight)

 

Shifting is as you’d imagine, smooth. I’d say it feel like shifting one gear is quicker than a mechanical set up. It’s less than a second from pressing the button on the paddle to hearing the chain move. And as of setting the gear up and trimming, I’ve not had to touch a thing.

SRAM reckon that there are millions of Eagle drivetrains being ridden around the world and this seems totally feasible, it makes sense that lots of these riders will want to make this kind of upgrade should they be able to afford it. SRAM also say this is going to appear on lots of eMTB’s over the following months and years, just like we see Shimano Di2 on top end e-bikes.

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2021 SRAM GX AXS drivetrain fitted-5 (Image Credit: Rachael Wight)

We’ll be publishing a full review of this soon as soon as I get more miles in on it. In the meantime, check out this article for more information on the rest of the AXS range. 

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