SRAM XX SL Eagle AXS Transmission review: equally at home on my enduro bike and my race bike

SRAM XX SL Eagle Transmission spec details

SRAM XX SL Eagle AXS Transmission weight and price details

• Total weight: 1,640g
• Price: £2,890 / $2,699 / €3,250

How I tested SRAM XX SL Eagle AXS Transmission AXS

This review is based on my experience of using two XX SL drivetrains – one that was fitted to three different long-term test bikes and one that came fitted to the Lauf Elja.

I started testing the first groupset in the autumn of 2023, and it was only removed from a bike in March 2025 when the Eagle 90 mechanical transmission arrived at my doorstep.

The bikes it was fitted to were the Merida One-Forty, Yeti SB120 and Last Glen – none of which are traditional XC bikes.

Although initially set up with the XX SL power meter cranks, I used a Race Face Era crankset and an XO-level crankset for some of my testing.

The second groupset, fitted to the Lauf Elja, has seen 12 months of consistent XC use, logging up plenty of training and racing miles.

Neither groupset has had a particularly easy life, especially because my attitude to bike maintenance is sadly a little lacking.

How easy is it to set up SRAM Transmission groupsets?

Setting up the groupset involves three phases – fitting the components properly, pairing them all together and tweaking their functions in the SRAM AXS app, and connecting the power meter.

Components need to be fitted in the correct manner for the shifting to perform. Key to this is the length of the chain, the correct use of the Setup Cog and Position, and tightening the Full Mount bolt and rear wheel axle in the correct manner.

Fortunately, SRAM’s app makes it easy to know which Setup Cog, Setup Position and chain length you need for your bike.

In terms of pairing, I had no issues. Flashing LEDs guide you through the process, and hint at battery life (which is more detailed, again, in the AXS app).

Adjusting the function of the buttons – how many multi-shifts they perform, for example – is also intuitive in the app.

I can’t claim to be an expert when it comes to power meters – my colleague Simon von Bromley is far more attuned. However, as part of my testing, I had to pair and unpair power meters a few times.

I found the AXS app a little glitchy at times, especially when it came to working with the Flight Attendant system, or updating the firmware on the components.

Often, a complete closure and re-opening of the app, and multiple attempts, were required for the updates or pairing to happen.

When it comes to calibration, other than the instability in the app, it is handy that it doesn’t require much knowledge of the system – the auto-calibration technology tells me, at least, that it’s done its job with minimal input.

Despite the app resets, with a brew on the workbench and a bit of patience, it all worked out in the end.

SRAM XX SL Eagle AXS Transmission performance

There’s no doubt that SRAM’s Transmission groupsets have rewritten the rulebook on how a drivetrain should shift.

The stiffness afforded to the derailleur, thanks to the bolt-to-the-frame Full Mount system, works with the X-Sync cassette and chainring tooth profiling, as well as the chain’s shaped plates, to provide top-quality shifting performance up and down the cassette under extreme duress.

With no cables to drag through outers, you end up with a completely consistent system, where a shift after one week of use feels no different from a shift six months later.

Durability is often lost when components lose weight, but that hasn't been the case with this groupset yet, nor has any shifting performance been sacrificed.

While cassettes and chains bed in together, I’m confident that 18 months of consistent use and very inconsistent maintenance have not detracted from the quality of the shifting through the system. Nor do any of the components, visually at least, look particularly tired.

Nothing is without fault, though.

SRAM’s stock Pod Controller shifter button layout is not as good as a traditional cable shifter’s levers. I’ve struggled to get the pods in the perfect place, especially when they’re paired with brake levers.

It’s easier with SRAM’s Infinite mount, where the Pods are mounted to the bar rather than the brakes, but they still fall short.

A swap to the AXS Pod Controller Rocker Paddle certainly improved things, with an easier ergonomic feel and a shift more of a flick than a press away.

The SRAM AXS app’s fragility has frustrated me at times, especially as a technophobe. Firmware updates often take a couple of attempts to push through.

However, the flipside is the app's functionality is excellent, enabling meaningful tuning of the groupset.

Oh, and the alloy SRAM DUB crank bolt still needs a scaffolding pipe to remove it after six months in place.

SRAM XX SL Eagle AXS Transmission derailleur, cassette and chain performance

The derailleur, cassette and chain work together to ensure power is transferred reliably to the rear wheel, while shifting gears smoothly across the block.

For this to work, the teeth on the cassette are heavily profiled, and the chain is shaped in a manner to enable this smooth transition between sprockets.

The derailleur’s movement is determined by when the shift is best placed to happen, rather than exactly when it is initiated at the bar.

This enables the chain to move while it’s over the correct shift gates on the cassette.

The result is shifting that really is as good as the hype.

Shifting supreme

When moving to a larger sprocket, the chain is picked up by the teeth’s profiles, hooking it onto the new sprocket with minimal complaint.

Exert all your watts, and there’s an occasional small grumble as the chain pops and pings off the leading sprocket tooth, but overall, the shifting experience is pretty much silent, other than the derailleur’s servo motor buzzing as the chain shifts across.

I’ve found the shifting is a touch better under more power, too.

Want to put a full-gas sprint in halfway up a steep ascent? A quick punch of the shifter’s button will get the chain onto a smaller sprocket as you’re unleashing your power.

Need to dump a load of gears when transitioning from a descent into a climb? The orderly procession of the chain over the cassette, as defined by the derailleur’s regimented shift movement, ensures this is almost always done without the usual grouchy crunching and clicking that can accompany such a move elsewhere.

Strong and durable

Durability is something that’s hard to judge here – but it seems impressive.

My maintenance regime is poor – the groupset has rarely been cleaned properly, often run far dryer than it should be, and with no consistency in terms of which chain lube has been used.

Despite this, the chain has remained rust- and corrosion-free, and those shifts, even when the chain is crying out for attention, have always been like butter.

This experience is also true of the derailleur.

It’s had its fair share of bangs, with plenty of scuffs to show, but the pivots in the mechanism are all without play, the pulley wheels still spin smoothly and the clutch is as strong as ever.

SRAM XX SL Eagle AXS Transmission power meter crankset performance

Despite rattling various bikes down many thousands of metres of descent, I’m yet to drop a chain with this groupset.

The derailleur’s clutch will play a part here, but it’s clear the X-Sync narrow/wide system does an impressive job of keeping the chain in place.

Wear levels on the chainring are also acceptable, with little dulling or noticeable shark-toothing.

The cranks have stood up well, too. However, I would recommend keeping the supplied crank boots in place. These help ward off scuffs when traversing technical terrain – mine have certainly seen some action.

They make fitting and removing pedals a slightly fiddlier process, because they can move on the crank arms a touch, but there's no reason to remove them.

There’s also some scuffing to the crank arms, from my shoes. However, it's far less visible on these carbon cranks than on alloy cranks. Overall, they stand up to aesthetic wear and tear well.

The power meter has performed well. I’ve had no issues with it connecting to my Garmin computer, and there’s a full suite of training data available from its dual-sided strain gauges.

In training terms, having a dual-sided system is preferable to a single-sided option, which uses estimations to provide a full set of data. Lower-tier Transmission groupsets forgo this dual-sided power meter, a plus point here for XX SL.

Battery life on the power meter has been fine – I’ve replaced the battery (an easy process) twice so far and had no reconnection issues after doing so.

The only issue I’ve had with the whole system has come from the integration with SRAM’s Flight Attendant, whereby swapping power meters linked to a Flight Attendant fork has caused some computational confusion.

That’s a story for a Flight Attendant review, though, and isn’t a fault of the power meters.

Being fussy, the proprietary Thread Mount crankset / chainring interface means if you want to put a non-power meter chainring on the cranks, you’re going to struggle to find many options.

SRAM AXS Pod Ultimate Controller performance

As shifters go, the Pod Ultimate Controller is as simple as they come. Two buttons make the gears either harder or easier. There’s a touch more to them than that, though.

Two sets of buttons are provided – a convex set and a concave set. I preferred the concave pair because my thumb sat easier between them, and I tend to press the upper edge of the top button or the lower edge of the bottom button.

In my experience, this makes it easy to feel what’s going on with the shifter.

There’s a subtle, but noticeable click when you press them, with more feedback than the AXS Pod Controller Rocker Paddle shifter of old – although you’ll get more feedback into cold, numb fingers from a cable shifter.

I struggled to get the AXS Pod Ultimate Controller into my ideal position under the brake levers.

Using MatchMaker clamps with SRAM brakes in my relatively flat lever position meant I struggled to get the Pods far enough towards me under the bar – perhaps I have small thumbs.

And, with the Infinity Mount, where a bar clamp connects the shifter to the bar, I still struggled with the ergonomics.

Although this is personal preference, I like the feel of a pushed lever on a mechanical setup. I also prefer their more slimline form, sitting closer to the bar, rather than hanging low underneath.

The Rocker Paddle version of the shifter improves things, though.

I've found it more intuitive to use, enabling more of a flick of the shift lever, rather than a press, and I found my thumb sat more naturally in its concave form.

The Rocker Paddle is also more solidly attached to the Shift Pod than the buttons are. On a couple of occasions, a brushing knee knocked the pads off the Pod, lost forever to the undergrowth, and leaving me shifting with a minuscule button for the rest of my ride.

SRAM XX SL Eagle AXS Transmission bottom line

With a number of other Eagle Transmission groupsets already having been extensively reviewed at BikeRadar, it is no surprise that this lightweight version also has benchmark performance levels.

SRAM will market it at the XC race crowd, but my experience of the groupset on bikes with more gravity intentions shows it doesn't shy away from the gnarlier end of things.

Comparisons will obviously be made to Shimano's new XTR Di2 groupset, however, the breadth of options with XTR means we haven't been able to complete a truly like-for-like review here.

XTR comes in at a very similar weight, but it costs considerably less, at around £1,400 / $1,800.

My colleague Alex tested the trail-orientated version of Shimano's XTR groupset here.

SRAM's XX SL Transmission performs almost faultlessly in almost every manner, with low weight, impressive durability, excellent shift performance and great looks.

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