SRAM AXS Revolutionizes How You Shift Bike Gears


Sometimes, news of a product release comes completely out of left field.  Minds across the internet get suddenly blown by a new technology that, just minutes before, nobody this side of an NDA had believed was even possible. The release of SRAM Eagle AXS (ACK-siss) is not that kind of news. SRAM’s wireless electronic road shifting technology, E-Tap, has been around for more than three years. And Eagle has been around for nearly the same. Ever since, we’ve just been waiting for SRAM to finally put the chocolate and the peanut butter together. Today is that day.

One thing that may have come out of left field, unless you regularly visit our industry’s many rumor mills, is the RockShox Reverb AXS. Until now, the world’s only experience with electronic dropper posts has been the Magura Vyron, which worked as a proof of concept but still suffers from noticeable lag time. I’ll admit, I expected the same from the Reverb AXS, but then I got time with it out on the trail.

The Basics

The AXS wireless system sends communications between the controls and the derailleur or dropper across SRAM’s own proprietary network. Meaning it’s not Bluetooth, though you’ll be using Bluetooth to customize your setup through your smartphone. Every AXS component is waterproof to an IPX7 rating. That’s more waterproof than IPX6 but less than IPX8. Duh. IPX8 is the highest on the IP scale, meaning IPX7-rated devices can survive reasonable pressure-washing and short periods of total submersion.

SRAM is simultaneously releasing XX1 and XO1 AXS, and though we still don’t have weights for each individual component, the total system weight for XX1 AXS is 5 grams lighter than its mechanical counterpart, and X01 is 15 grams lighter. We also don’t have prices for each individual component. SRAM’s first priority was sorting out OEM sales, which usually means entire groupsets. In this case, that’s crank, cassette, chain, controller (which I may accidentally call a “shifter” out of habit), derailleur, battery, charger and an AXS-specific setup tool. That big red box will be available aftermarket this coming April at $1,900 for XO1 and $2,000 for XX1 (€2,000/£1,900 and €2,100/£1,950 respectively). The derailleur and shifter will be available on their own somewhere around four weeks later, but there’s no word what that slightly smaller red box will go for. The Reverb AXS will also be available in April, will go for $800 (€800/£700) and includes the controller, post, battery and charger.

The Batteries

Each controller uses a replaceable and common CR2032 watch battery, and SRAM claims they will stay powered for as long as two years. The derailleur and seatpost both use the same proprietary battery SRAM has been using on its eTap road derailleurs since they were launched. That interchangeability means that if you’re using both Reverb and Eagle AXS and one battery loses power before the other, you can swap your working battery to whichever device is more crucial at any given moment. SRAM claims most riders will get upwards of 20 hours of ride time out of a derailleur battery and 40 to 60 hours out of the dropper. There’s a button on the derailleur and post that triggers a battery life indicator light, telling you whether you’re mostly full, half full or mostly empty. Once you are empty, the battery detaches with the flip of a plastic tab and charges in about an hour. Replacement batteries go for $42 and weigh 25 grams.

The Derailleur

The derailleur itself has a similar silhouette to that of existing Eagle derailleurs, other than the battery at the rear. But it’s got a few subtle design tweaks. The pulley cage is slightly shorter, offering better ground clearance, the body is slightly farther forward, offering better chain wrap, and it sits very slightly farther inboard, offering a little more breathing room. But if that’s not enough, and you do bash your AXS derailleur on a rock, it’ll engage the Overload Clutch. Unrelated to the chain-retention clutch that controls the pulley cage motion, the Overload Clutch disconnects the internal motor from the derailleur body in the event of an impact. Not only does that protect the motor itself, but ideally it would allow the derailleur to move freely, protecting itself as well as the hanger. After the impact, the motor automatically reconnects and, assuming it wasn’t too severe, you could be on your way again without ever stopping.

The Seatpost

The Reverb AXS is available in the same configurations as the hydraulically actuated Reverb, those being lengths of 100, 125, 150 and 170 and diameters of 30.9, 31.6 and 34.9. And despite the seemingly bulky battery and motor assembly beneath the rails, the minimum exposed length on the Reverb AXS is not any longer than that of a traditional Reverb. There’s no adjustable return speed on the Reverb AXS. It’s set wide-open like every traditional Reverb should be set anyway. What it does have is Vent Valve, a feature popping up on some other posts. Vent Valve is a way to purge air that might creep its way into the oil chamber inside the post. Depress the valve, compress the seatpost, and the air is clear. The guts also got some refinement leading to less friction and quicker activation. And that activation works essentially the same as any other dropper. To compress, push button, sit down, release button. To extend, stand up, push button, release button.

The Controllers

The Eagle AXS and Reverb AXS controllers mount just like any other under-bar control from SRAM, using either its own clamp or the Matchmaker system. They’re not any more bulky than a traditional shifter and are of course much sleeker-looking with no cables or barrel adjusters. Rather, there essentially is a barrel adjuster, but not like you’d think. Underneath the shifter, there’s a button that used either to pair the shifter to the derailleur or to adjust it. Hold the button down and click the shifter in one direction or the other, and the derailleur will move a tiny fraction of a shift. Line it up like you would if you were adjusting a cable. There’s also the stop screws, which work just as they do on a traditional derailleur.

The Reverb controller is simple enough. In about the same place your thumb would find the paddle of a Reverb 1X remote, it’ll find the broad panel of the left controller. The Eagle AXS shifter is a little more unorthodox. There’s technically only one trigger that will hinge up or down to shift one way or the other. Your thumb rests in just one spot. Press it forward like you’re pulling the cable on a traditional shifter, and you shift one way. Or, press your thumb up against a sharkfin molded into that panel and you shift the other. There’s also a piece of that single trigger that extends behind the thumb trigger and above the shifter body, which is in the perfect place for your knuckle to contact if you want to sneak a shift with all five fingers wrapped around the bar.

The Options

If you’re using both Eagle AXS and Reverb AXS, you technically end up with a total of three buttons. Given that there are no cables and no wires, there are no rules saying what those buttons need to do. The AXS companion app lets you get under the hood and control your controls. If you want to keep it traditional, the one button on the left controller will actuate the dropper post and the two buttons on the right will actuate the shifter. But you can chose which of those buttons upshifts and which downshifts. Or if you want to mix things up, you could assign the left controller to an upshift, the broad panel on the right controller to a downshift, and the sharkfin to control the dropper. Once you choose which button shifts which way, you can then control what happens when you hold that button down. In the app, you can choose to leave it at a single shift or set it to drop two, three or all the gears at once until you let go. And of course, upshift and downshift preferences can be set independently. All of these preference changes take effect instantly. While you’re getting used to it, you an experiment with different settings on the trail until you find what feels intuitive.

The control’s ergonomics are already plenty intuitive. The buttons themselves activate with enough motion that it’s clear that your fingers are actually doing something. They’re not shallow clicks like the home button on an iPhone.  You don’t feel the disconnect that you might think you would when driving by wire. And to my surprise, the new shape of the right control paddle feels just as natural. My right thumb has spent most of the past five years clicking the same two buttons in the same two places. When I saw that AXS relocated one of those buttons, I was ready for my muscle memory to put up a fight. But 10 minutes in, my thumb was shifting like a local. There was also a noticeable benefit to not needing to swing my thumb underneath the shifter and back again when shifting one way or the other.

Once you’ve pushed the button, the shifting itself feels traditional in some ways and foreign in others. It’s traditional in that the same rules apply as do to cable shifting. SRAM claims AXS offers measurable benefits when shifting under load. And although AXS’s precision ensures the derailleur is putting the chain in the exact right place at every moment, I still found a familiar limit to how much force it could handle the instant before the chain reached its new home. The last time I closely evaluated this aspect of a drivetrain, it was on Shimano’s new XTR, which seemed to encourage these bad shifting habits. SRAM AXS, on the other hand, makes them easier to avoid.

That’s what I found to be foreign about shifting with AXS. Pleasantly so. I haven’t spent prolonged time in the dirt with electronic shifting, but I’ve had it on my road bike for the past six years. It’s almost clairvoyant. Riders have come to take for granted the delay in even the straightest, best-adjusted, slickest, cabled traditional drivetrains. But electronic shifting is instant. Until you eventually adjust to it, the shift can happen before you’re even ready. But just like the ergonomics of the shifter itself, adjusted I quickly and happily.

I found something similar in the dropper post. Most importantly, there is zero perceptible lag between activating the remote and releasing the post. I expected a small delay that I would eventually get used to. Sort of the opposite of what I felt in the shifting. But no. It is instant. Both when pressing and releasing the trigger, the post’s inner workings opened and closed precisely when I told them to. Now, you might say that a cable-actuated dropper is just as instant. And you’d be right. The motion of opening a valve inside a dropper is far simpler than moving a chain from one cog to the next. But what’s different when using the Reverb AXS is what happens immediately before that.

We take for granted the thought and energy that goes into swinging a lever to drop a saddle. It takes force. It takes time. It takes redirecting the actions of muscles in our forearm that we’d otherwise be using to keep our hands on the grips. There may even be some motion in the wrist or the heel of the palm. We get really good at it, but it is a distraction. That goes double for shifting. Proper shifting is a skill. We’re feeling through our skin for when the lever hits the ratchet point to indicate we can release. We’re coordinating that sensation with what our legs and bodies are doing below. We’re compensating for the slow, inevitable increase in friction throughout a cable’s short lifespan. And just like actuating a dropper lever, that all takes physical effort and unwanted motion. It takes physical effort that should be focused on controlling the bike. But more than that, it takes mental effort. No matter how skilled you become at shifting, it still takes thought and concentration. And it happens hundreds, maybe thousands of times every ride. It may seem on the surface that electronic shifting is just another gadget. Just another shiny fascination for the technophiles. But in a surprisingly pure sense, it is a way to make our ride better.