New SRAM X0 Eagle AXS: First Ride Thoughts

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The new SRAM X0 Eagle AXS drivetrain requires a UDH equipped frame. Why? To enable a direct bolt-on mounting method that’s designed for robustness and ridiculous shift under-load capability.

  • Brand: SRAM
  • Product: X0 Eagle AXS
  • From: SRAM
  • Price: £590 mech, £160 shifter, £430 cassette, £105 chain
  • Tested: by Benji for 2 weeks
Mounts either side of UDH frame and around the thru-axle

This groupset – or ‘transmission‘ as SRAM is keen for us to call it – has been a long time coming. It’s been on the cards since sometime around 2018 apparently. The whole XD driver and UDH mech hanger stuff is very much integral to how the new Eagle AXS stuff operates.

In the past five years SRAM has shifted(!) approximately 7 million Eagle drivetrains to the bike market. It’s fair to say that Eagle has been very much a success story. And let’s not forget to give muchos kudos to SRAM for pretty much inventing modern 1x drivetrains for mountain bikes.

And, to be frank, we’ve always liked SRAM Eagle stuff. Especially the Eagle AXS wireless stuff. We made the SRAM GX Eagle AXS drivetrain one of our Editor’s Choice 2022 highlights.

Rear mech is UDH specific

Front view

The big story about the new SRAM Eagle AXS transmission is that is only fits on bikes that have the UDH mech hanger fitting. If your bike doesn’t have UDH, you can’t run this new system. SRAM are keen to point out that there are over 200 bike models out here running UDH, with. more being added all the time.

Not that this new mech attaches to the UDH mech hanger by the way. It doesn’t. The UDH hanger gets removed and the mech mounts directly in its place on to the bike frame.

With the rear wheel out

Note: it mounts to the frame. It does not mount to the thru-axle. So it’s a bit different to other ‘direct mount’ rear mechs we’ve seen in days of yore. Once installed on a bike, you can remove and reinstall the rear wheel in exactly the same way you always have done. The process is no different to a regular mech-ed bike.

No more replaceable mech hangers then. This will no doubt set various keyboard warriors’ alarm bells a-ringing. Which is fair enough. It made us raise our collective eyebrow too when we first heard of this.

Rear view

What happens if you bend the mech then? Essentially, SRAM simply claim that you won’t. And we’re happy to repeat those claims. The rear mech is flipping well sturdy.

You will no doubt see on The Internet this week various people laying their bikes driveside-down and then standing on the rear wheel axle with their full weight going through the rear mech. Nothing bends. No issues. Like we said, robust.

We have the X0 version on test

Partly to allay fears of breakages – and some riders will always break stuff in extremes – the rear mechs are re-buildable and there are going to be spares available (skid plate, B-knuckle, shroud, pulley cage etc).

Exploded diagram

And let’s not forget the way that AXS mechs can quickly move out of the way (and return to position) when they do receive a blow. Every little helps and has been factored in.

The whole mech sits more ‘in’ and ‘up’ away from harm

In a fortunate bit of timing for SRAM, we here at Singletrack World have just had a couple of incidents with trad mech hanger bikes. We had an ebike that we bent the hanger on. We also had a regular bike that we snapped the entire gear hanger off from. The ebike was limited to two functioning gears for the rest of the ride. The regular bike was essentially a very expensive balance bike until a replacement hanger arrived in the post.

So, those were both good reminders that the existing method of attaching mechs to bikes is not perfect.

See the red ring?


In terms of installation and setup, the new SRAM Eagle AXS is simultaneously easier and more complicated than a regular drivetrain. It’s easier in the sense of no more screw setting faff. Yep, there are no limit screws or B-tension screws anymore. There is a small bit of indexing still required to finish off.

You do though have to follow a set procedure when first installing a rear mech. It involves putting the chain in a specific gear (coloured red on the cassette), some tightening then backing-off of frame bolts and other stuff.

Backside view of the cassette

In other words, in terms of setup faff – you win some, you lose some.

There are two B-tension positions to choose from on the mech. A and B. We think the best way of thinking of these is A for ‘ardtail, and B for bouncy bike.

A or B

Full suspension bikes need a bit more chain length to them to deal with chain growth under suspension compression.

It’s meant to be bent

The final couple of things about the rear mech: yes, it looks bent from behind (don’t worry) and the lower jockey wheel is ‘magic’. By magic we mean that it still spins if a twig (or similar) gets stuck in the gaps between its spokes. The outer teeth are mounted on a carriage that can spin independently of the main jockey wheel axle.

The Magic Jockey Wheel

Shifter pods

There is a new shifter ‘pod’ design too. It’s ambidextrous and has a decent degree of tilt/swivel/lateral adjustment to it. The shifter pod itself has two buttons on the front (for, you know, shifting) and a discreet button on the back (used as a pseudo barrel adjuster for quick indexing tweaks).

Shifter pod

The micro adjust the indexing you hold down the button on the rear of the pod and press whichever of the two buttons on the front you need to move the mech’s bias towards. As we said, pretty much a barrel adjuster, but not.

‘Barrel adjuster’ button

Cassette and chain

The cassette is simply an amazing piece of design and engineering. Through a process SRAM call “cassette mapping” there are multiple pathways and (off)ramps that the chain follows when changing gears.

Truly gritty

The new mapping of the cassette means you no longer have to ease off the pedals when changing gear. At all. Hammer the heck along and press your shifter pod buttons and it just works. No jerks. No clangs. No expensive sounding noises at all.

The ability to keep full load going the pedals during gear shifts is seriously impressive. It’s especially noticeable uphill on steep gradients at slow cadence. The chain just crawls nicely from one sprocket to the next. Both upshift and downshift.

This is despite the whole cassette being also now fully X-Sync narrow-wide toothed. Better retention AND gear shifting.

The chain is now flat-topped. It’s flat topped simply to add strength (more material = more strength), although the side benefit of it looking cool doesn’t hurt.

Flat-top chain

X0, XX and XX SL but no GX

There are three different tier of the new Eagle AXS.

Eagle XX and XX SL are the top-end lightweight tiers. The XX SL being the super XC racers’ choice. Hollowpin chain and evz. Not ebike rated.

XX is £2,195 for complete transmission. XX SL is £2,355.


Eagle X0 is the more all-round rider tier. That said for the complete transmission (inc. cranks etc) it costs £1,715. It’s SRAM Eagle X0 AXS that we’ve been testing for the past couple of weeks (mounted to a Specialized Turbo Kenevo SL).

As you can imagine for something that is going to be specced OEM on a lot of bikes, there is a huge array of skews and variations of the new SRAM Eagle AXS transmissions. Crank lengths, power meters, chainrings, ebikes, normal bikes etc etc etc.

Interested? View a PDF of the full SRAM Eagle AXS skews.


The new mech, cassette and chain only like to work with each other. It’s not advisable to run any of this new Eagle AXS stuff on older Eagle componentry. At the very most, if you’re an existing AXS user you can keep your shifter and your chainring. But to run the new Eagle AXS stuff you need to get the mech and the cassette and the chain.

Wheel comes out as-normal for punctures etc

For the purposes of this First Ride Review, we’re going to restrict ourselves to talking about our experience of the SRAM Eagle X0 AXS transmission that we’ve been testing.

SRAM X0 Eagle AXS First Ride Thoughts

Let’s get the niggles out of the way first.

Niggle 1. It is expensive.

Niggle 2. I [Benji] am not a fan of the new two-button shifter pods. I prefer the previous AXS rocker paddle shifter. I’m currently finding button pressing during hectic moments of offroad riding to be a bit lacking in feedback. Both shifter designs are not as audibly or finger ‘clicky’ as cable shifters but I do find the rocker paddle more positive in operation; I know that I’ve rocked that paddle. Buttons just lack feedback for me. I’d actually welcome a ‘beep’ setting as confirmation. (I’m now wondering if a beep mode is possible via the app ‘settings’ – I’ve asked SRAM, will let you know ASAP).

I still prefer the paddle

Aside from those two niggles though, this new SRAM X0 Eagle AXS transmission is brilliant. Which comes as no surprise to anyone. Why wouldn’t it be? The previous AXS was brilliant.

At first it can be a bit underwhelming. Possibly even disappointing because it doesn’t shift quite as slickly as a high-end cable-actuated drivetrain. But then you stop doing the whole easing-off-the-pedals thing when changing gear (which is hard to unlearn after three decades!) and the true nature and appeal of new Eagle AXS appears.

Shift whenever the flipping heck you want. And it’s fine.

The gear changes may not be as imperceptibly slick as off-the-gas trad high-end drivetrains are but… stop riding like that. You don’t have to do that anymore. Keep your full weight/wattage going through the pedals and SRAM X0 Eagle AXS shifts equally as well as SRAM GX (or Shimano XT).

Like a lot of technological improvements on a bike, it’s only really when you go back to the system you had before that you notice just what the new system’s benefit is.

To put it bluntly, going back to another bike – not equipped with new SRAM Eagle AXS – sucked. I never realised just how much of my riding brain was preoccupied and taken up with easing-off-the-pedals to change gear.

More riding time required before we commit to a fully finished review. For now though, this is a very impressive piece of kit.

Any questions?

Post in the comments. We have a lot of info about the new SRAM Eagle AXS transmissions and didn’t want to kill you all with info just yet!

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Review Info

Brand: SRAM
Product: X0 Eagle AXS Transmission
From: SRAM
Price: £1,715 complete transmission
Tested: by Benji for 2 weeks
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Cotic RocketMAXer. Schwalbe Magic Mary Purple Addix front. Maxxis DHR II 3C MaxxTerra rear. Coil fan. I have been a writer for nigh on 20 years, a photographer for 25 years and a mountain biker for 30 years. I have written countless magazine and website features and route guides for the UK mountain bike press, most notably for the esteemed and highly regarded Singletrackworld. Although I am a Lancastrian, I freely admit that West Yorkshire is my favourite place to ride. Rarely a week goes by without me riding and exploring the South Pennines.

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Viewing 23 posts - 41 through 63 (of 63 total)
  • New SRAM X0 Eagle AXS: First Ride Thoughts
  • RickDraper
    Free Member

    Shame I have only one bike it will fit on!

    Free Member

    utter nonsense. 1x not an improvement over 2x or 3x. Come on now… 🤣🤣🤣🤣🤣

    Heavier, less range, more fragile, and far more expensive.

    Full Member

    for those talking about patents, Bikerumor (sory) did a patent patrol article a few years back. Admittedly most of these articles include a large amount of speculation, but it’s still good to see what’s being thought of.

    Patent Patrol: Direct thru-axle mounted, hydraulically damped SRAM rear derailleurs

    also a bit about the shift ramps

    Patent Patrol: Shimano, SRAM, & Campagnolo all file major drivetrain updates


    Full Member

    Heavier, less range, more fragile, and far more expensive.

    Depends what you buy. I run mid cage XT 12 speed and that is (Relative to 1x) lighter, less but still adequate range, definitely no more fragile and certainly less fickle and prone to derailling, and quite cheap relatively speaking.

    Full Member

    Before I never spend any money on this is there an easy way of finding out if your bike has a UDH?

    Free Member

    there’s a lookup on sram’s website
    It’s also usually listed in the frame spec of your bike

    Free Member

    Before I never spend any money on this is there an easy way of finding out if your bike has a UDH?

    How old is your bike? Think it only appeared in 2019. The text UDH is usually printed around the driveside rear drop out if it uses UDH. mine has a UDH, but I wont be rushing to replace the drive train just yet….. cost needs to come down quite a lot.

    Free Member

    I got the impression from one review that there are variations of the UDH and not all are suitable for AXS Transmission.

    Full Member

    back to what we always could do with 2x or 3x!

    1x is a reaction to the introduction of larger wheels not transmission complexity.

    Full Member

    Heavier, less range, more fragile, and far more expensive.

    No bash guard, constant chain drops on anything remotely bumpy, chain suck mangling frames, never in the right chainring, cluttered bars, more cables, more maintenance.

    Anyway, I think the argument about 1x Vs 2x/3c has been done to death.

    It’s the future, Get onboard old men.

    Free Member

    1x has also freed up space for alternative suspension designs.

    Look at high pivot bikes.
    Think about anti squat and anti rise when there are 3 different chain rings (although I think it was advantageous on my old turner 6 pack).

    Free Member

    Heavier, less range, more fragile, and far more expensive.

    Wrong, wrong, almost wrong and wrong. In my experience.

    And what about the upsides?

    Full Member

    I’ve always said, the time to launch a £3k groupset is in the middle of huge financial strain around the world and massive inflation

    Full Member

    The sorts of folks that’ll buy this groupset now; aren’t personally really suffering massive inflation or financial strain

    Full Member

    I don’t think the photos really sell it for me, they remind me of this (takes hybrid commuter out of shed, fills watering can, takes photo)… 😀


    Yeah nothing like it, but whatever. The photos look like it’s covered gunk.

    edit: yes the kit has been used for review, but the colour scheme of the kit bleuuuighhhrrrr, gunk, but it really doesn’t matter because it’s waaaaaay out of my price range.

    Full Member

    Apologies if others have mentioned this, but I get that the mech is strong and will take a whack, or a fat bloke mysteriously jumping up and down on it, and also I have personally experienced that mech hangers do not save mechs but they do save frames when things really go south.

    I’ve bent a few hangers with whacks and thumps, but I’ve only snapped them, and mangled mechs, from sticks in spokes. I think 3x over teh years. mech mangled, hanger snapped, frame ticket boo.

    I’m not buying AXS yet, but what happens with a stick in the spoke? with a big tough mech do I now say bye bye to mech and frame?

    Free Member

    So why is does the mech look bent form behind ?
    I heard ‘dont worry about it’ buy not the why ?

    Also doent this system rely on the frame manufacturers getting their tolerances spot on from the factory – mech hanger alignment tool is not going to help anymore

    Free Member

    there’s plenty of videos of fat blokes standing on the mech (well, not so fat) but a lot heavier than id be happy with on any of my kit

    it looks bent from behind so the top pulley aligns with the cassette sprocket, lower pulley aligns with the chainring

    only tolerance the frame manufacturer would need to get right is the size of the through hole, and thickness of the axle flange itself that the mech sits on. as the cassette butts to the mech hanger part.. the tolerances then all become SRAMS issue.

    Free Member

    anyone remember the derailuer hanger savers that kind of mounted the derailuer to the frame in the same way as this direct mount derailuer is – ie it resulted in the derailluer being cantilevered off the axle rather than hung from a hanger?

    I had one on a specialized enduro in about 2007 – I’m trying to google for a photo.


    this is the best I can find, it wasnt one of these, but worked in the same way, was made by shimano I think

    Full Member

    Got to touch the groupset in my LBS today, didn’t jump up and down on it but was surprised how big and heavy the mech is and how light the “cheap” cassette is. The shifter looks like a tiny speedplay pedal

    Free Member
    Free Member

    All the videos I’ve seen of people standing on mechs they’re standing on the axle, which seems kinda pointless to me. I’m glad it’s strong there, but the most vulnerable point will always be the bottom of the cage, near the bottom jockey wheel.

    I’m disappointed, but not surprised by Cy’s comments that not all UDH frames will accept this new groupset.

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