New SRAM X0 Eagle AXS: First Ride Thoughts

Mar 28, 2024

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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

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.

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).

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.

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.

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.

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.

Yep.

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.

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.

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).

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.

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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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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Looks great. Lots of good ideas and some questions.

Will they continue this alongside existing Eagle AXS or is it a total replacement? For frames without a UDH, this is a non-starter and pretty much narrows my groupset choice with my existing frame.

Too cheap for me. I’m waiting for the psychic version with no shifter.

I’ll wait for the sentient AI version that’s better at gear selection than me.

The rear mech is flipping well sturdy.

Lol. I’d love to test that claim here in the Lakes…

You know, it’d be nice if they put any money towards an actual ‘proper’ sized reverb AXS. It’s 4 years old now.

This new groupset does look good, I’ll admit – as a current AXS owner – but my frame doesn’t have a UDH so I’ll never be a potential customer unless Nicolai come out with a retrofit UDH, which I can’t see happening.

Looks perfectly rational, but is it going to be an open standard, or are Shimano going to bring out the SDH next year and we’ll be locked into whatever system the OEM choses?

I’m just impressed that your chain is as filthy as mine 😀

Edit: Casette cost jumps out at me. Is there any real reason it won’t work with another 12sp casette? Appreciate it may not shift as well under power but casette and chain are £535 alone. Could be a way to save some cash.

Looks perfectly rational, but is it going to be an open standard, or are Shimano going to bring out the SDH next year and we’ll be locked into whatever system the OEM choses?

the “UDH” was an open standard allowing any normal mech to attach

this attaches to the place where the UDH hangar attaches (removing the need for the hangar)

current shimano will therefore work on anything (using a UDH hangar) that the new Sram stuff works on, but I dont know if Sram have patented the concept of direct mount.

This completely replaces AXS. They also aren’t updating the mechanical drivetrains so if you don’t have UDH then it’s mechanical only. It’s completely not backwards compatible. Even the chainline of the cassette is different. It’s wider, which means it runs into your frame if you committed to UDH Revision E 2 years ago, and they didn’t properly disseminate the information for Revision G with the Transmission information in it. Not all UDH frames are equal……

Transmission cassettes are 2.5mm wider chainline that any other cassette. With the direct mount rear mech, they have put the cassette effectively where the dropout cowl is on a regular frame, so that cassette will foul the dropout face plane of any other frame even if it uses a regular UDH hanger and other SRAM rear mech.

So there are different versions of a Universal hanger that aren’t compatible with each other? More of a Multiversal Derailleur Hanger then innit?

All the versions of UDH are compatible with eachother. The direct mount transmission rear mechs are necessarily compatible with frames designed to earlier versions of UDH.

if you don’t have UDH then it’s mechanical only

I read that existing AXS was remaining in production for us non UDH types?

Sounds utterly awful.I’m sure STW will love it.

thegeneralist doesn’t like it, sounds like it could be good

Wasn’t the mech hanger there to protect the frame as well as the mech?….

thegeneralist doesn’t like it, sounds like it could be good

I wasn’t gonna bother, but now I’ve seen this, I’ll be putting an order in.

So replaceable mech hangers ideally give you a cheap (UDH are only about £15) part that breaks to save both the frame and the mech. Now many times that doesn’t actually work – many times over the years I’ve ended up with both a bust mech and a bent hanger, but sometimes it did.

This makes the replaceable part an (expensive?) part of the mech. But what protects the frame? I’ve heard horror stories of UDHs (and some other manufacturers more recent hangers) rotating and wrecking the seat stay. How is the frame affected if the first stage of the mech gets bashed in different directions?

Honestly, what kind of wizardry justifies a well over 100 percent rise in the RRP of a chain? I know SRAM chains are supposed to last well, but still…

According to the embargoed video that I watched, current AXS and mechanical drivetrains aren’t going anywhere. IIRC the guy hinted at new stuff coming too. It’d be commercial suicide to stop supporting consumers that have current bikes that don’t have a UDH, given that the vast majority of bikes out there don’t. Maybe things will be different in 10 years time….

Many things putting me off as an electric shifting convert. Overall price is obviously the biggest & also lack of cross compatibility – it’s only going to work with a flat top chain, that costs how much??

Just annoying that they’ve opened up use of the UDH, and tried to closed options on chains and cassettes – or am I missing something.

I’ve axs on two bikes (and another form of electric shifting on another) and really happy with them, but I cirtainly couldn’t justify the ‘upgrade’ for the stiffer rear mech and slightly better shifting under load. Shifter also seems like a step backwards – more like the archer components v1….

Ill wait another few years for the price to drop and compatibility to improve.

According to the embargoed video that I watched, current AXS and mechanical drivetrains aren’t going anywhere. IIRC the guy hinted at new stuff coming too. It’d be commercial suicide to stop supporting consumers that have current bikes that don’t have a UDH, given that the vast majority of bikes out there don’t. Maybe things will be different in 10 years time….

Exactly. Even SRAM aren’t stupid enough to stop supplying chains/cassettes/mechs etc to thousands of customers who haven’t or can’t upgrade to the latest AXS stuff. The ‘old’ Eagle AXS stuff isn’t going anywhere soon.

phew.. cant work on any of my bikesmassive relief that it works just as good as my xt drivetrain that cost 10% of this probably

Just how long will a £500 cassette last?

And you’ll only be able to run those flat-top chains, too. Which are not great.

…and I’m annoyed about dropping £70 for a new SLX cassette every year.

Really makes you think 🙄

Just how long will a £500 cassette last?

Based on how long previous iterations have lasted, kin ages.

and I’m annoyed about dropping £70 for a new SLX cassette every year.

How many miles are you doing to have to replace a cassette yearly?! 😲

Based on how long previous iterations have lasted, kin ages.

Yup, I don’t exactly do the most miles but I’ve got 2000km over 3.5 years on an X01 cassette and XX1 chain and they’ve still got a huge amount of life left.

How many miles are you doing to have to replace a cassette yearly?!

Tbf, it’s probably not yearly. It’s not the miles, it’s the incline. It’s up or down here, very little rolling terrain. I spend most of my time climbing in gears 1-3, so they wear much faster than the rest.

With now both SRAM and Shimano having 12 chains and cassettes that can shift very well under full load, why does SRAM’s top of the range cassette cost £645 and the chain is £160, where the XTR one costs £330 for the cassette and £60 for the chain. Why such a difference? It’s insane!

STD. Sram transmission development

sorry feeling childish

So does this stop working in a much more efficient time than the older version? 😉😂

Those prices are batshit mental.

April 1st already?FFS look at those prices, and it doesn’t shift as well as XT?APF 🙁

So the main benefit of this kit is that it allows you to do what Rapid Rise did 16 years ago?

Oh, and why kudos for 1x? I’m on board with it but still not convinced it’s any real kind of improvement as the manufacturers seem to spend all their time increasing range back to what we always could do with 2x or 3x!

I’ll out myself as no fan of Sram though, which may cloud my judgement.

it costs £1,715

How much more fun will it make my ride if I fit it instead of Deore?

Oh, and why kudos for 1x? I’m on board with it but still not convinced it’s any real kind of improvement as the manufacturers seem to spend all their time increasing range back to what we always could do with 2x or 3x!

Ha! I’m sorry, I know a good amount of mtb’ers are opposed to any sort of progress or improvement in technology and bikes, but this is just utter nonsense. 1x not an improvement over 2x or 3x. Come on now… 🤣🤣🤣🤣🤣

it costs £1,715

The launch price of X01 AXS, in 2019, was £1900.

And here we are, a few years later, with a GX AXS available for a few hundred quid.

GX AXS available for a few hundred quid

With cassette and chainset?

I’ve thought for a long while that the extra reach needed on modern wide range cassettes puts significantly more leverage through a mech hanger than ever before. It seems much more involved to keep on top of mech hanger alignment.

Something like this needed to happen.

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Forks

mildred

22 hours ago

Nottingham, England

500.00