If you're going to make a wireless 12-speed drivetrain, you might as well throw some of that technology at your dropper post, right? That's exactly what RockShox have done with the new Reverb AXS that uses an encrypted wireless network in place of the normal Reverb's hydraulic hose. The post's travel is still non-indexed, and it's controlled by a funky, button-style remote, with 100mm, 125mm, 150mm, and 170mm travel options.
If this is what the future looks like, the future ain't gonna be cheap; the Reverb AXS will sell for $800 USD when it hits the shelves this coming April. SRAM hasn't released a weight yet, but they say that it's within a few grams of the normal Reverb, so expect it to come in around 650-grams with its remote.
Reverb AXS Details
• Travel: 100, 125, 150, 170mm
• Electronic, wireless design
• Re-designed head, clamp
• Faster, fixed return speed
• SRAM battery, CR2032 in remote
• Lengths: 340, 390, 440, 480mm
• Sizes: 30.9, 31.6, 34.9mm
• Weight: TBA
• MSRP: $800 USD
• More info: www.sram.com/rockshox
Inside the Reverb AXS
So, what exactly is happening when you push the remote's button? And why isn't this thing called the E-verb? I only know the answer to the first question, with the gist being that RockShox has combined existing wireless tech with tiny electric motors and batteries.
Let's start up top with the remote, pictured to the right.
Without the need to pull any cable or, in the hosed Reverb's case, push some oil, they were free to come up with an entirely new remote. The new AXS ''controller'' (their words, not mine) sees a wide, easy to hit thumb paddle that's tucked up close to the underside of the handlebar so you don't have to unwrap your thumb to hit it. You're also probably a lot less likely to smack it with your knee for the same reason, and because it's now a literal button (under the paddle) rather than a lever, it only needs to travel a few millimeters before activating the post.
The remote is larger than I expected - after all, it still needs to house some electronics and a CR2032 battery - and it's on the same AXS program as the drivetrain, so you can customize the "controller touch points" to your liking.
Another tidbit worth noting is that there seems to be plenty of room on the remote for SRAM to add in another button, say if one wanted to be able to control their suspension lockout, maybe? Further integration down the road is very likely, even if SRAM wouldn't comment on their long-term plans.
You need to press that small button on the back of the remote to pair your Reverb AXS, something that also keeps ''friends'' from messing with your bike. The AXS app lets you choose which button controls what, from the shifter to the Reverb remote.
Want the Reverb remote to act as a shifter and one of the "touch points" on the right-hand remote to operate your seatpost? That takes all of about thirty seconds using the free AXS app that's available for iOS and Android devices. My boss wants to yell at me daily for not understanding or using Google Docs (ugh, they're my personal TPS Reports), but even I figured out how the AXS app works pretty quickly.
Now to the seatpost itself. Think of it this way: with the notable exception of the Vent Valve (more on that later), the Reverb AXS remains largely the same as its forebearer from the stanchion down. That means it's still a twin-tube layout, and there's still an internal floating piston (IFP) that separates the air and oil, albeit an updated one to go along with improved oil and grease. But from the top of the stanchion up, things are drastically different.
The SRAM battery that clips onto the back of the Reverb AXS is the same as what's used to power the wireless Eagle AXS drivetrain. On the Reverb, SRAM says you'll get around 40-hours of battery life.
The original Reverb actually uses two separate hydraulic systems: the post's internals, and the remote and hose. Put simply, the only thing the traditional Reverb's hydraulic remote does is open and close an oil port on the seatpost. All other hydraulic posts need the same job done, of course, but they do it with cable-operated remotes instead.
A few years ago RockShox decided they wanted to do the same job but without any hoses or cables.
From left: the battery mount and cover, the post's head with the plunger still inside (the small red part), the circuit board, and the motor with the gearbox attached.
To do that, a small electric motor needed to be squeezed into the post's head, which was no small feat. First, the right motor needed to go in there, and it had to be powerful enough to open and close the oil port, but it also couldn't require too much juice. The answer is the same tiny motor that's found in the Eagle AXS derailleur that spins up to something like 80,000 RPM. Just like the derailleur, the Reverb AXS has its own RC car-sized gearbox to handle all the RPMs and torque required to open and close the oil port.
Wireless and electronic or not, the Reverb AXS still needs that oil port to open and close for it to be able to go up and down through its travel. This is also what gives the Reverb the infinite range feature that allows you to move it a few millimeters at a time or make your seat disappear under you.
The motor sits inverted on the head, with the gearbox activating the plunger.
The motor sits inverted behind the re-designed clamp, with the tiny gearbox at the bottom that aligns perpendicularly with a plunger. When you hit the remote with your thumb, a signal is sent through an encrypted wireless network to a receiver hidden inside the post's head. Technology does technology things at this point via the circuit board, and the little motor goes from zero to full torque instantly. That's put through the gearbox that then depresses the plunger and opens the oil port, and then the post is free to go up or down.
I think that it's important to point out that none of the above is a feat of engineering or pushing the limits of technology. Sure, the packaging is impressive, but as long as it's been executed correctly, the technology itself isn't something that we should be shunning, especially when it comes to dropper seatposts and drivetrains.
There are a couple of other things to mention beyond the whole 'no wires' angle, the first being something called Vent Valve. I don't think it's out of line to say that RockShox invented the squishy dropper post when they invented the original Reverb - it worked well when it worked, but it could also be the world's most annoying suspension post. That's caused by air and oil mixing inside of it and, well, air being squishy and all...
The fix is to bleed the post's hydraulic system, a daunting job for the average rider that's far beyond doing the same to the remote. Vent Valve is the answer, RockShox says, and it's essentially a built-in way to push the air out of the system without having to bleed the thing. All you have to do is flip the post upside down, depress the stiff Vent Valve button (that is also the top of the air valve) with your thumb, and then compress the post while a friend activates the remote. It's a two-man job [edit: only if you use the remote. It's a one-man job if you use the button on the Reverb].
If that sounds similar to what BikeYoke has going on inside their Revive post, that's because it is, only RockShox uses an IFP to keep the air and oil separated, and BikeYoke does not.
You might have to do it a couple of times, but it takes all of a minute or two and the Reverb goes back to being rock solid under your ass. Not gonna lie, I bet a lot of people would have liked this feature on their older Reverbs, too. Sadly, it isn't retro-fittable.
No, that's not a seat bag. The Reverb AXS' electronics required a complete re-design of the head to fit everything inside. Along with that came a new way to make seat angle adjustments.
All of that computer stuff, along with the electric motor and gearbox, required RockShox to ditch the proven twin-opposing bolt head design for something that looks like a single-bolt setup at first glance. Thank God it isn't, though, because those terrible things are just terrible. Instead of depending on just the single bolt that clamps the seat's rails to also hold the angle, there's a second, locking bolt that's used to adjust tilt. You still need to back off the clamp bolt, but once that's done you turn the second bolt to make angle adjustments before locking everything back down.
The electronic internals necessitated the head's re-design, but this new setup is also far easier to deal with than the common opposing-bolt layout.
Enough about what's inside of it; let's get onto how it performed.
No Hose, No Worries?
The usual press camp disclaimers apply here and to any so-called "first ride reviews'' that you may read elsewhere - we all got two or three rides in on the Reverb AXS dropper while in Tucson, Arizona, which isn't enough time for a proper review. That said, the early impressions were quite positive all around.
My Reverb AXS and Eagle AXS wireless drivetrain were installed on a Yeti SB130. It turned out to be a great bike for the rocky, pointy terrain that surrounds Tucson.
Yes, it goes up and down as it should, and the non-adjustable return speed is faster than the previous models. It also makes cool 'vvvvt
' sounds when it does its thing. Most importantly, there's no delay between you pushing the button and the motor opening the port - it is much, much faster than Magura's Vyron dropper. It also feels damn near instantaneous next to a normal Reverb.
Part of that is down to not having to push a lever (or plunger on older Reverbs) through its stroke, however short, to activate the thing... Because it's literally a button that you push, the activation speed seems to be about on par with flipping a light switch and having the room brighten up.
The Reverb AXS' action is faster, especially because there's no lever or plunger to depress; think lightswitch kinda speed.
The new button-style (sorry, it's a ''touch point'') remote also lets you easily make those smaller micro-adjustments in seat height that you might do if you like steep, technical climbs, or if you like to tinker to match whatever kind of terrain you're on. All you do is push on the button using the edge of your thumb so that it merely grazes it, which is enough to lower the seat by maybe 5mm or so. That sounds useless when I describe it now, but it's certainly not on the rolling, rocky trails around Tucson that dart up countless rises and through even more dry washes. Amazing trails, but they're a lot of hard work for someone in the middle of a Candian winter.
The Reverb AXS was almost trouble-free. Mine refused to raise back up on one occasion after being lowered for a tricky righthand corner that I probably deserved to crash on, although it was sorted out within a few seconds after we removed the battery and re-installed it. No word on the cause, either, and I asked around but no one else had a similar issue. Technology, amirite?
There are a few other things to note as well, especially the fact that no one is going to be able to "hack" into your Reverb and take control of it. Just like the Eagle AXS drivetrain, the post runs on an encrypted wireless network that's paired to the contro... er, remote, and you need physical access to the component in order to pair it because you have to depress the pairing button. You have to know the component's serial number, too. Russia probably doesn't care about your E-verb, either, so no worries there.
As for battery life, the little CR2032 that's up in the remote should last for a couple of years, and there's a button on the side of the Reverb to activate it if you manage to run the remote dry or break it in a crash. And speaking of that, RockShox does plan to sell replacement paddles, and maybe even offer a few different versions to boot. I expect some aftermarket options to pop up as well. As for the important SRAM battery on the post itself, it's the same as you'll find on the back of the Eagle AXS derailleur, meaning that you can swap them around if need be. I was told to expect around forty-hours of life from it (double the drivetrain battery's life), which should be thousands of up and downs, and a warning light will tell give you its status. It only weighs 25-grams, too, so you could easily carry a spare with you.
This isn't a review, but I was pretty impressed with the performance of the Reverb AXS, aside from that unexplained stuck-down moment. After just two days on it, I know that I'm going to prefer the wireless AXS model over the traditional design. Funny thing, though, is that I don't say that because there's no hose, but rather because the wireless design necessitated some much-needed improvements to the Reverb as a whole. Yes, even over the last update.
There was plenty of fun to be had on Tucson's trails, especially when you can make your seat disappear at the blink of an eye.
Not only is the Reverb AXS much, much quicker than its predecessor, it is also far easier to modulate the travel due to how the remote is designed and because the action is instantaneous. Vent Valve is obviously a godsend, too, and the whole thing does away with that silly hose as a bonus. Well, maybe it was the other way around, but the bottom line is that the Reverb AXS shows a lot of potential. The only thing left to do is to spend a good chunk of time using one and find out if it's reliable.
If everything checks out, do you think you'd be willing to part with $800 USD for the wireless Reverb AXS?