Words & Images Liam Friary
RRP $1,488
Distributor Worralls

Analogue aficionados rejoice—cable ain’t dead! In fact, it’s far from dead with the recent launch of SRAM’s new Eagle 90 Transmission. A few years back, we saw the launch of SRAM’s electronic AXS Transmission which removed the traditional derailleur hanger by hanging the derailleur directly onto the frame.

This brought the benefits of strength, shifting under load, and improved shifting performance. Well, now all of this is offered in a more affordable mechanical version, which is great news—especially in the current economic climate.

There’s two new mechanical groupsets; SRAM’s Eagle 70 and Eagle 90. These are both 12-speed, cable-operated drivetrains, offering mechanical alternatives to their electronic counterparts. Eagle 90 is basically the mechanical version of GX AXS Transmission. It uses the same cassette, chain and crank arms, but adds a new steel chainring, plus a mechanical derailleur and shifter. Eagle 70 is the step-down option that replaces NX Eagle. It’s essentially the mechanical version of the S1000 Transmission, sharing its crankset, chain and XS-1270 cassette. One advantage: the cassette works with the more common HG freehub standard. It’s difference from the Eagle90 derailleur, is that it utilises cheaper materials and a Drag Spring damper to keep costs lower. For this review, I’ll focus on the Eagle 90 Transmission which I’ve been riding for a few months. You can purchase the complete SRAM Eagle 90 Transmission groupset with exception of BB. From a pricing perspective, its more expensive than Shimano’s XT mechanical drivetrain but cheaper than SRAM’s GX AXS Transmission.

Eagle 90 Installation is a simple setup procedure. SRAM’s “Prepare. Hang. Tighten.” motto is mostly accurate, but if you’ve spent years working on traditional derailleurs, there’s definitely a learning curve—you need to forget some old habits. That said, after the first installation, the second and third will go much smoother.

The “Prepare” step involves checking SRAM’s website or using the AXS app to enter your bike details (brand, model, frame size, chainring size). The system then gives you your specific chain length, cage lock position setting (A or B), compatible chainring sizes, and which cog to use for setup. SRAM provides excellent installation videos that cover the little details that help achieve perfect performance.

Overall, installation is straightforward—any decent home mechanic can handle it. Just be aware of a few things: changing chainring size or adjusting dropouts can affect shifting. Also worth noting: SRAM emphasizes that T-type drivetrains are very sensitive to proper torque specs, so use a calibrated torque wrench when installing both cassette and derailleur.

The Eagle 90 Derailleur uses a Full Mount design that connects straight to your frame without needing a separate hanger. There’s a catch though—it only works with UDH (Universal Derailleur Hanger) dropouts, so if you’ve got an older mountain bike (non-UDH), you’re out of luck. A standout feature is that the derailleur is rebuildable. If something breaks or wears out, you’ve got options: you can replace just the skid plates, get new P-Knuckle or B-Knuckle assemblies, or even grab a bushing replacement kit. The jockey wheels and inner cage are also available separately, or you can buy the complete package with the full cage and damper. This is a strong move away from the disposable culture of ‘break it, throw it, buy new’. The ‘right to repair’ movement has been gaining serious momentum lately—not just in cycling but across pretty much everything we own. From phones and laptops to cars and tractors, people are pushing back against manufacturers that make it nearly impossible to fix your own stuff without specialised tools or proprietary parts.

The cage on this derailleur is the same as the GX AXS Transmission model—steel on the outside, aluminum on the inside. Pretty cool feature: you can take off the whole assembly and damper from the main body without needing any tools. And since it’s modular, you could upgrade to a high- end version from an X0 or XX SL derailleur if you wanted. So, the Eagle 90 derailleur is a solid unit weighing in at in at 390g. However, its 100g lighter than the GX AXS version, which is welcomed.

The Eagle 90 Shifter features a brand-new trigger shifter with a specific cable-pull ratio for T-Type derailleurs and cassettes (not compatible with older Eagle systems). It comes in double-click for regular bikes or single-click for eMTBs, with a smaller plastic upper paddle for upshifting and a larger, textured aluminum lower lever for downshifting. Installation is flexible—use SRAM’s MMX system to either mount it directly on your handlebar with a standalone clamp or attach it right to a SRAM brake lever with the appropriate adapter. One nice detail: the cable runs straight and parallel to your handlebar, which looks super clean when paired with SRAM’s newest Stealth brakes.

The Eagle 90 Crankset shares the same alloy arms as the GX AXS, just with a black finish and steel bolt. It’s built for the modern 55mm chain line and uses a DUB Wide spindle. You can get arm lengths from 155-175mm, plus there’s a special eMTB version for Bosch and Brose/Specialized motors. I opted for shorter 165mm cranks on my set up.

The big difference from the GX AXS is the new one-piece steel chainring. It’s twice as heavy as aluminum but lasts three times longer and runs quieter. Thanks to the modern 8-bolt interface, you can easily swap to a lighter alloy ring or add a power meter if you want. The crankset comes in 30T, 32T, and 34T sizes, and includes standard two-piece bash plates.

The Eagle 90 Cassette uses the existing XS-1275 cassette from the GX AXS drivetrain. It needs an XD freehub body and works best with the 55mm chain line spacing. This cassette delivers a massive 520% gear range with its 10-52T spread. Construction-wise, the eight largest cogs use a pinned design while the smallest four form a single mini-cluster. The big 52T sprocket is aluminum for weight savings, and all the others are nickel-plated steel for better durability. A key feature is the narrow-wide tooth profile (X-Sync) that matches perfectly with the chain, creating better retention and specific shift gates in both directions—this is what allows for such reliable shifting even when you’re pushing hard on the pedals.

The Eagle 90 Chain uses the same GX Flattop chain from the existing lineup. It features the distinctive Flattop design that’s specific to Transmission systems and comes with a PVD coating that helps fight wear and corrosion. To keep costs down, the GX version uses solid pins instead of the lighter hollow pins found on higher-end SRAM chains. But it still includes the same convenient Powerlock master link that makes installation a breeze.

Eagle 90 Transmission Riding—to date I’ve probably done around 150-200km of riding with the new groupset. It’s plenty enough to get acquainted with its performance but not nearly enough to report on durability and longevity. However, from that first ride up until writing this review its been bloody good!

The smooth shifting does great under load, with positive engagement and a quietness to the drivetrain. Often, it’s so damn quiet you don’t even know you’ve shifted. For the last two decades, I have been used to backing off the pedals when shifting. Transmission effectively removes that from the equation, however, it does take some getting used to. I did find that the mechanical version of Transmission prefers shifting when under load. I should point out that the system shifts just two gears at a time. Interesting, perhaps, but it makes sense and is a smart design decision that likely helps keep gear transitions smooth when you’re putting power through the drivetrain. It’s a small detail, but it’s these thoughtful touches that contribute to how well the whole system performs.

There’s something about the tactile feel when thumbing the shifter up or down gears that resonates. Maybe it’s because I’ve been riding bikes since before there was electronic shifting, but there’s a certain appeal to the analogue feel. The lever ergonomics of the shift paddles are superb, especially that concave profile on the upshift paddle—it’s like it was designed specifically for my thumb. From the first ride, the natural feel, comfort and shift experience really stood out. Of course, this shifting is on par with what you’d expect from this level of groupset. It’s solid, dependable and functions really well. Sure, it’s not high-end X01—but that’s not the point here, and it keeps the price lower.

It’s been good riding the groupset at a variety of different locations. I’ve been on multiple rides in Rotorua and found that on the steeper fire roads and singletrack, shifting under load—or rather, last minute—before a feature (or if my heart rate soared too high) it found the gear without hesitation. Shifting under load is a real standout feature. Basically, it removes any thinking about gear changes and allowed me to focus on the line, putting down power to grind away up a fire road or tackle technical features.

On the descents, the silence continued—thanks to an improved clutch for Transmission—and after numerous rides, the components have only gotten better as they’ve bedded in. During my rides in Rotorua, I had a couple of stacks—nothing major—and the robustness of the derailleur meant I could dust off, grab my bike and continue on the trail without any shifting issues whatsoever. I did slam the bash guard against tree roots a couple times while rolling but, again, it just shrugged it off like it was nothing. No damage, no drama.

After tweaking the cable tension, I haven’t run into any real problems with the Eagle 90. Like any cable system, you’ll need to do regular maintenance—which is different from electronic derailleurs that generally keep shifting well for longer periods. On the plus side, there’s no battery to worry about charging— so each system has its own advantages and disadvantages. I personally like the fact that there’s nothing to charge—or remember to charge!—before heading out for a ride.

Another good addition is the advanced technology delivered to this groupset, while still being realistically serviceable. Unlike older derailleur designs that often meant replacing the entire unit after a good smack on a rock, these T-Type models let you swap out specific components—the outer parallelogram link, skid plates, derailleur cages—without throwing the whole thing. Perfect if you’re abusive with your bike and don’t want an expensive electronic mech hanging off your bike.

I noted earlier that shifting is best under load, as it can feel sluggish if soft pedalling. It actually performs better when you’re more aggressive—kind of counterintuitive but that’s how it works. This takes a bit to get used to but you soon adapt. It hasn’t skipped a beat since I’ve been on it—precise and crisp. Given how well it handles high-torque shifting, I bet it’ll be fantastic on eBikes with motors adding extra power through gear changes.

All in all, the new SRAM Eagle 90 Transmission is a pretty sweet addition to the mountain bike drivetrain scene. It basically takes all those cool features from the electronic versions— no hanger needed, super simple setup—but without emptying your bank account. The clear standout is shifting under load, which is seriously impressive. I’m also into that ‘click’ feedback that only mechanical can deliver. Sometimes, the analogue world prevails over the pressing of electronic buttons and dealing with apps and dead batteries.

Yeah, it’s a bit heavy—especially the cranks— and it’s not as boujee as the higher-end product from SRAM, but it doesn’t lack any performance benefits. It’s also pricier than other mechanical groupsets, but the Full Mount design eliminates a lot of the usual headaches that mess with shift performance and durability. The Eagle 90 Transmission is bloody good!