Review: 6 Months with SRAM'S Wireless Eagle AXS XX1 Drivetrain

At a certain point, adding another cog isn't going to do much. Some will argue that we crossed that line more than a few years ago, but here we are in 2019 with twelve cogs, one of them the size of a pie plate, no front derailleur, a huge gearing range, and not much to moan about on the performance front. And you don't even need to hand over your entire savings account to get it, with SRAM's GX group delivering everything most of us will ever need for around five hundred bucks and a 400-gram penalty over the more expensive bits.

So why bother spending three or four times that amount on the fancy stuff?

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It's not apples to apples, but let's compare AXS XX1 to its mechanical counterpart when it comes to price and weight. At 1,451-grams for all of the components, AXS XX1 is actually 5-grams lighter than cable-operated XX1, despite the batteries. There's a bit of weight saved by not having to use a steel cable and housing, and the clip-on battery is just 25-grams. AXS does cost $500 USD more, but you're not paying for the weight loss - you're paying for the wireless control.

What about 11-speed XTR Di2? Keep in mind that Shimano released their wired electronic drivetrain four years ago so it's a bit dated at this point, and it's down a cog as well. Not entirely fair, but here it is. Depending on how you set it up, you're looking at around 1,600-grams for a single-ring drivetrain and a $1,990 USD price tag. The newest mechanical XTR, M9100, has been impressing us since we got on it a few months back, and it costs about $1,435 USD. It weighs around 1,568-grams before you add the necessary cable and housing.




The Details

The derailleur: This thing is pretty neat. You know, for a derailleur. Hidden inside is a tiny electric motor that spins at 80,000 RPM, as well as a tiny gearbox that converts that to left and right action. Your derailleur has just one clutch? Eeesh. With AXS, you get two of them; there's the usual one-way clutch at the cage pivot for chain retention, but there's also the very important-sounding "Overload clutch." Its job is to isolate that tiny gearbox from impacts, like a rock strike or even just your bike falling over.




The ominously named clutch uses a one-way bearing, a friction device, and a little cylinder that slides in and out to release the gearbox from the derailleur, but all you'll hear is the faint "vvvvt'' sound of it realigning itself a split second after impact. Like a $700 robot.

The Eagle AXS XX1 derailleur weighs 350-grams on my scale, without its 25-gram battery clipped onto the back of it.




The shifter: Without a bunch of gear wheels and the need to pull or release a cable, SRAM had the opportunity to go with a sleek, integrated design that might have even been difficult to spot at first glance. Instead, what they came up with looks a lot like, well, a shifter. For good reason, though; after making a bunch of different prototypes, it turned out that big ol' easy to reach paddles made the most sense, and there needs to be room for the CR2032 battery as well.




If you had a derailleur inferiority complex, you're about to have a shifter complex. While your shifter has two paddles, this one has three. The two under the bar are mostly where you'd expect them to be, but there's a third button that can be reached from above by bumping it with the knuckle of your pointer finger. It's the knuckle button. You can use the AXS app to configure which buttons do what, and if you have the e-Verb dropper post, you can have all four buttons however you like.

The Eagle AXS XX1 shifter weighs 82-grams on my scale, including the CR2032 battery and standalone clamp, and it costs $200 USD.




The other stuff: The $449 cassette is the same 363-gram X-Dome job from SRAM's standard XX1 group, and the same goes for the $85 chain, both of which get the divisive 'Rainbow' finish that I'm a fan of. Plenty of others aren't, though. Could you ever imagine Shimano using such a color? How about never. The cranks are the very light (436-grams w/ 34-tooth ring) XX1 Eagle Dub SL arms that go for $515 USD.

Batteries are included, with the derailleur being powered by the same 25-gram, clip-on unit that gives life to the e-Verb dropper and their Red road drivetrain. SRAM says to expect around 20-hours of juice when it powers the AXS derailleur, which is about half as long as when it's being used on the seatpost. A small LED lets you know when it's time to stick it in the charger. Up at the shifter, there's a CR2032 watch-style battery that you can find at your closest corner store when it dies after a couple years of use.




There's also a free companion app (iOS and Android) that isn't required to use AXS day-to-day, but it does allow you to customize the function of all your new buttons. You can make your Reverb button on the left shift to a lower gear, that weird third 'knuckle button' on your shifter can control the post, and the last button can drop to a higher gear. Or any other way you might want to do it.


How it all works: It has to wake up before it goes to work. All of the AXS components will auto-sleep, just like me, and auto-wake if you do so much as move your bike by a few millimetres. You grabbing your bike will jolt the computer to life, and when the time comes to shift, a signal is shot out to the derailleur over an encrypted wireless network, at which point the little motor fires up from zero to mach chicken nearly instantly. All you'll hear is the 'vvvvt,' a sound you better get used to, of the derailleur moving the chain.



Installation

How long does it take to install AXS? It takes far longer to remove your old cable-controlled relics than it does to put on the new derailleur and shifter, at which point it's time to introduce the two and tell them to talk to each other. You do this by holding down the pairing button on the derailleur until it flashes green, then doing the same to the shifter. Lastly, turn the pairing off by pushing that derailleur button again.




You'll need to set the usual limit and B-tension adjustments (it comes with a chain gap tool, so zero excuses), but there's obviously no cable tension to adjust. I lieu of that, a trim function lets you make micro-adjustments to where the derailleur sits. Hold the shifter's pairing button down while shifting in the direction it needs to go and it'll move ever so slightly; the top pulley wheel needs to line up with the cog when you're in the second-highest gear. Because it moves the exact same amount with each shift, it'll also be lined up with the other twelve cogs.

I reckon most people get could this on their bike and running within 20-minutes, including taking off your off old drivetrain. And if you can pair a Bluetooth speaker to your phone, you can pair the AXS components as well. SRAM even has a great how-to video that's worth watching.





Performance

Yes, I get it, there's absolutely nothing wrong with your mechanical drivetrain or how it performs. Of course, I understand not wanting to be hours into the forest only for your battery to die; charging is just one more thing to remember. I realize that you already know how to shift gears, too, and the last thing you need is help from some gosh darn computer.

But this AXS stuff is good. Really good.

First, let's really boil down how to shift, and especially what you're doing with your thumb. Regardless of whether you have a SRAM or Shimano drivetrain, you simply push the thumb paddle when you want to change to an easier gear, right? Kinda, but things are happening that probably come as second nature to you. Picture the chain in the middle of the cassette but you want to shift to the next larger cog. You know to push the thumb paddle, but not too much because then you'll shift two gears instead of one, but also to push it until you feel the first click and then maybe just a smidge more to get the chain over there. It's just pushing the thumb paddle, sure, but there's a technique to do it correctly.




If you've been riding for a year or two, you probably do all that without thinking much about it, and quick. It's not exactly difficult, even in the heat of a technical battle with rocks and roots, but don't kid yourself: Even today's single-ring drivetrains require skill and timing to use smoothly, and they'll tell you when you don't get it right.

AXS doesn't let you make mistakes, though, and the shifting offers perfect, metronome-like consistency. Every. Single. Time. Just like XTR Di2, in fact, but without the giant cigar battery and rat's nest of wires.

The paddles give a tactile 'click' when you hit them, and one push will give you one shift - it's a button, so there's no throw to it. You can hold the paddle down and the derailleur will move the chain over the entire cassette in either direction, but that particular task is still done faster with a cable. If you're in a small cog and need to dump to a much easier gear in a hurry, pushing the mechanical thumb paddle is going to be quicker. AXS is just as fast as a mechanical drivetrain when talking single shifts, though, but it doesn't feel any faster.




Shimano's new mechanical XTR group does beat AXS in one area: Shifting under heavy pedalling loads. The fresh XTR is magic at shifting when you're not supposed to, whereas AXS seems to be about par for the course on that front.

That said, holding the AXS paddle down is certainly easier than pushing a thumb paddle through its entire stroke once, and especially if you need to do it twice. If you have hand issues, as one rider did who used this very AXS test group, it's tough to beat how easy AXS makes it as lever throw is a thing of the past. It's not quiet, though, with a 'vvvvvvt' sound coming from the derailleur every time you push the paddle. You'll get used to it, but it'll be fodder for your riding buddies until the novelty wears off.

No word of a lie, I can't say there was a single bad shift over more than sixty rides and 45,000 meters of vertical gained and lost. Muddy? The robot don't care. The hose? The robot don't care. Getting beat up by Whistler Bike Park's braking bumps for hours on end before heading to the GLC for some well-earned chicken strips? The robot definitely don't care.


Maybe too easy - I sometimes found myself shifting by accident, either from tapping the button more than I wanted because I was getting a bit loose, or just accidentally hitting it with my hand. Turning the multi-shift function off in the app solves this. AXS is all about consistent, easy use, and flexibility, so you might as well make an effort during set-up to get the most out of it.

Reliability has been good, but there are a few non-AXS-related grumbles to report on. The sixty-ish rides that have been put on the drivetrain were split between myself and another rider, with the numbers adding up to right around 45,000-meters of climbing and descending. In that time, battery life sat around three weeks, or about fifteen to twenty rides, before the red LED said it was time to give it some juice. We both went past the twenty-hour mark multiple times before charging, but terrain and fitness, and therefore how much you shift, will be a big factor in battery life.




I wasn't quite brave enough to keep riding until the battery was fully drained, but there's zero degradation in shift performance well into the red light being on. The only thing that stopped AXS was a broken chain, likely due to a shift under heavy load that caused a tooth to peel one of the chain's outer plates from the rivet. It's not all that common these days, but I've also broken a Shimano chain in the last year or two.


Would I buy it? For me, $2,000 is a hell of a lot of coin, regardless of what I'm spending it on, but that's just a decent night out for a lot of other folks. To be fair, I doubt that I'd drop $1,500 on mechanical XX1 when GX does the things I'd need it to do... But, if I was going to spend that kind of money on a drivetrain, I'd do my best to come up with another $500 to lose the cables and housing. It is that good. Alternately, pairing an AXS derailleur and shifter with a less expensive crankset and cassette isn't a terrible idea.






Pinkbike's Take:

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Reviews and Tech Reviews Drivetrain SRAM Eagle Axs Xx1