Sram GX AXS: First test of the mid-range MTB wireless drivetrain

A basic characteristic of electronics is that there is a plus and a minus. As far as the AXS electronic wireless shifting system from Sram is concerned, the plus seems to be bigger than the minus. At least in terms of function. As the AXS system does not require any cables at all, there is no longer any need to replace worn cables. The constant readjustment due to dirty cables is also a thing of the past with wireless. The presented two years ago, the AXS shifting system from Sram should have long since begun to replace the classic cable circuit - or so you might think. But just as before Shimano's cable-based electric shifting Di2 Sram's AXS technology has not yet made it beyond the niche market. This is due to the drawback that is inevitably associated with electric technology: firstly, the significantly higher price compared to the cable version. And secondly, the limited battery capacity, which makes regular recharging necessary. The upgrade kit for the electric version presented two years ago costs around 1100 euros. Sram XX1 AXS - which is around 400 euros more than the classic XX1 version with shift cable.

The big question was: Will the topic of wireless switching fade away as quietly as it came? Or will it herald the great shifting revolution after all? With the brand new GX AXS, Sram now has the answer. Compared to the XX1 AXS, the more favourably priced drivetrain is supposed to represent something like the mid-range. At just under 620 euros for the upgrade kit - rear derailleur, controller, battery, charger, adjustment tool - the GX almost halves the price of the high-end version. This is made possible by the use of simpler materials. For example, the derailleur cage is made of steel instead of carbon fibre and the ball bearings of the derailleur pulleys are also made of steel rather than ceramic. Otherwise, however, the GX AXS rear derailleur and the controller are almost identical to the XX1 AXS. Especially as all electronic components come from the premium version, which makes sense in view of the advantages of series production. The major visual difference lies in the plastic battery cage with which the GX AXS is supplied. The part offers no real functional advantage, but is rather intended to minimise potential buyers' fear of battery loss. However, this is minimal either way, as thousands of Endurance test kilometres with the XX1 AXS without this cage.

Mathematically speaking, the new GX AXS is pretty much the same drivetrain as the XX1 AXS. Although the controller and rear derailleur set weighs 76 grams more in the mid-range version, it also costs around 500 euros less. Casual: the name of the GX colour, which shimmers between black and anthracite. "Luna Grey", yeah!

How does the GX AXS shift? Is it worth switching from the classic GX Eagle? And can you feel a difference to the expensive high-end XX1 AXS version, at least in practice?

Prices of the individual Sram GX AXS components

• Rear derailleur (without battery): 385 Euro >> available here
• Controller: 155 Euro >> available here
• Battery: 49 Euro
• Battery Case: 20 Euro

First test of the Sram GX AXS: Off to the trail!

Anyone who is familiar with the XX1 AXS should be briefly told at this point: the function and feel of the new GX version are exactly the same. Even riders who have already travelled thousands of kilometres with the premium drivetrain will not notice any difference. For those who have used traditional cable-operated shifting up to now, electric shifting is a whole new world. A little information first: The wireless set, i.e. rear derailleur and controller, weighs just under 120 grams more than the normal GX rear derailleur including shifter. However, the Bowden cable, shift covers and end caps (totalling just under 80 grams) almost completely cancel out the weight advantage. The real differences lie in the shifting characteristics and the feel of the lever. Unlike the usual trigger, where the shift command is triggered by tapping, the thumb on the GX AXS controller lies in a kind of cup. Instead of tapping, a swiping movement upwards or downwards gives the command to switch. Thumb twitch upwards = lower gear. Thumb jerk down = higher gear. Or vice versa. The mode you like can be easily selected using the AXS app thanks to the Bluetooth interface of the smartphone and shifting components, even on the trail.

The GX AXS responds with lightning speed and precision, but shifting with it feels unfamiliar for wireless newcomers. As the controller is physically decoupled from the rear derailleur, the gear jumps in hectic situations are less precise than with a cable shift, where you can literally feel the engagement of each individual gear in your thumb. In factory mode, the GX AXS shifts each gear individually, click by click. If you prefer a brisker pace, you should set the app to stepless mode. The AXS then manoeuvres the chain across the entire sprocket set at a gallop. This is where it really comes into its own compared to the classic GX drivetrain, especially when downshifting. With the latter, the chain can be lifted up a maximum of five gears with the press of a thumb. Downshifts are only possible click by click. However, the risk of shifting is greater with the AXS. In the heat of the moment, you only have to stay on the controller a little too long for the chain to go too far. We therefore recommend the optionally available Rocker paddle from the Sram accessories range recommended. The 19 euro item, which can be fitted in no time at all, is ergonomically reminiscent of the classic trigger and can be operated in a similar way - by tapping instead of swiping with the thumb.

And what about reliability? The unwavering success of the cable-operated gearstick to date is also partly due to the general scepticism of many bikers towards electronics. The common prejudice is that they are too susceptible, but this has not proved to be true in the course of many hard kilometres ridden by the BIKE crew. There were no technical breakdowns during our tests. The AXS technology is robust. Neither riding in the pouring rain nor in ankle-deep mud could harm the models we tested. The only real Achilles heel of the AXS drivetrain is the battery life. This is much longer than the small battery would suggest. However, depending on the outside temperature and riding style, it has to be recharged every two to three weeks. A diode indicates the charge status when required. If it lights up red, the battery (which can be unlocked and removed with a click) needs to be charged. Crossing the Alps without recharging is conceivable, but if in doubt we recommend investing in a replacement battery. This costs 49 euros and is the same as for the XX1 AXS.

Conclusion on the Sram GX Eagle AXS

The GX AXS works perfectly. It is reliable and makes wireless technology affordable for many who could previously only dream of it. The new mid-range leaves hardly any arguments in favour of the classy XX1 AXS, which costs 500 euros more but weighs just 76 grams less. The function of the two drivetrains is identical. If you have financial leeway and are not stressed by the battery management, you can buy the GX AXS without hesitation. Purists and savers are better off with the classic cable-operated version, which is only half the price.

Incidentally, the GX AXS* is compatible with all AXS components and will be available immediately. However, only for retrofitting for the time being. The drivetrain will be available on complete bikes from model year 2022, i.e. from around autumn this year.

Is radio the future?

"The better is the enemy of the good, so the saying goes. But what is better and what is good when it comes to circuits? The question can only be answered vaguely, if at all. Neither mechanical shifting nor electronic shifting has exclusive advantages. The favourable price speaks in favour of the Bowden cable version. And the idea of being able to cycle independently of the power grid is also an important argument for many. However, the dirt-sensitive cables that require regular maintenance become annoying over time. With the wireless solution, you don't have to worry about this, but the battery needs attention. AXS also costs significantly more to purchase. Both solutions have their justification, but the GX AXS could herald the creeping end of the Bowden cable. Electronics can be produced cheaply in large quantities. The big difference between the classic rear derailleur and the AXS version is basically just a servomotor and a few circuit boards. At the latest when wireless shifting competes with the Bowden cable version in terms of price, the course will be set for a wireless future. If only because manufacturers will be happy to dispense with the fiddly and therefore costly installation of cables in view of the installation effort and costs. As a result, cable guides in the frame could become superfluous. And as soon as that happens, it's a done deal anyway. Shimano, as recently leaked, has now also applied for a patent for wireless shifting. It is highly likely that wireless will become the new standard at some point. When exactly? Nobody can say as of today."

Does the end of the Bowden cable on MTB drivetrains come close?

What remains is the question of whether the GX AXS heralds the creeping end of the Bowden cable. After all, wireless technology simplifies assembly considerably, which is a good argument for series manufacturers, as labour time is expensive. We asked product managers and engineers.

"We very much welcome the fact that Sram AXS technology is being transferred to a lower price point. Customers love the lightning-fast shifting, and nobody will notice a difference in shifting comfort compared to the more expensive XO1 AXS and XX1 AXS. We have some very exciting models with the GX AXS planned for model year 2022. Wireless not only means easy maintenance for the customer, but also makes initial assembly easier for us manufacturers. It's also an important step towards system integration."

"Cable routing is always a challenge! And on an MTB, you often have to go through the most critical spot anyway: the right-hand chainstay yoke. Always thicker tyres on the inside, the chainring on the outside and then, depending on the design, a curvy passage. However, for reasons of stiffness alone, the cross-section here is acceptable with a 4 mm gear casing. And you also have to soberly realise that there will always be a hydraulic brake line running to the rear and, on many bikes, a dropper post line also runs through the frame. So you'll never get it completely super clean, even with wireless shifting. And there are certainly also customers who prefer the simplicity of mechanical shifting in off-road terrain. You can help yourself if something happens on the road. Or the fear of wrecking a rather expensive component on the trail may prevail."

"Until now, electrical circuits were reserved for the high-end sector. By expanding the range to include lower-priced segments, these are naturally becoming accessible to a much larger target group. This is also reflected in our range. Personally, I'm a big fan of electric circuits, whether with cables or without them at all. Installation is much easier, the design is getting cleaner and cleaner and these groupsets also open up completely new possibilities in terms of ease of use and customisation options."