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
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
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.
Set-up
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.
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).
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.
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.
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.
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.
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.
Compatibility
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.
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).
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!
More Reviews
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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