SRAM NX Eagle Drivetrain Review - MBR

New 12-speed groupset SRAM NX Eagle breaks new ground with the most affordable wide-range 1x drivetrain yet. Twelve speeds for £365 SRP.

>>> Mountain bike groupsets: buyer’s guide

While SRAM has recently soared higher than ever before with the pricing of its Eagle AXS wireless drivetrain, last year it swooped down to earth with the value-orientated NX Eagle, and we’ve been riding it ever since.

For £365 you get a shifter, cassette, chain, DUB-compatible cranks, r-mech and a B-tension tool. On top of that, to make it rideable, you have to buy a cable and housing and a DUB bottom bracket, but considering you can buy the drivetrain online for considerably less, it’s still impressively affordable.

To put it into context, NX Eagle (at suggested retail prices) is £130 cheaper than GX Eagle, with the biggest saving to be found with the cassette. To do this, SRAM has reduced the Eagle’s wingspan: instead of 10-50T, NX Eagle is 11-50T. It’s still 12-speed, making it (almost) fully compatible with all the other Eagle drivetrains, but you still sacrifice around 10 per cent at the top end of the gearing. The reason for this is simple – NX Eagle fits the older splined freehub design instead of the unique XD driver used by GX and upwards. As such it’s a double-edged sword. On the one hand it gives you a wider choice of wheels and hubs, and will make upgrading to Eagle simpler and cheaper for some people. On the other hand, if you choose to upgrade from NX to one of the more expensive Eagle drivetrains further down the line, you will have to buy a new freehub body, which will add to the cost. Also in the name of affordability, the cassette uses stamped steel sprockets, four of which are pinned to an alloy carrier and eight of which are separate. As such the PG-1230 cassette is a heavy lump of metal. It weighs well over 600g – 166g more than GX Eagle and 254g more than XO1 – all of which is unsprung weight on a suspension bike. Along with a rear derailleur that’s 60g heavier than GX, this means you won’t be able to enjoy ultimate suspension performance if you run NX Eagle as the bike will feel less sensitive than it would with a lighter set-up.

Elsewhere the shifter and derailleur both use more steel and plastic than aluminium, but the construction and finishing are first rate and only a close inspection reveals any cost-cutting over the high end versions.

In addition to our sample drivetrain we’ve racked up the miles on many NX Eagle on test bikes over the last seven months, including plenty of e-bikes as it’s the only SRAM Eagle drivetrain recommended for that application. On the whole our experience has been very positive, but we have had a few issues. So first the lows.

As we’ve already pointed out, that cassette is hefty, which has some knock-on effects. Because you can put so much torque through the 50T sprocket, if you run it on a softer alloy freehub body you may find the cassette winds into the splines and becomes difficult to remove.

The rear derailleur hangs really low, making it particularly vulnerable to damage from rocks, stumps and flying debris. Despite having the redesigned lower pulley with raised shoulder, we’ve broken and bent a few Eagle rear mechs now, including our original NX sample. It’s hard to say exactly what’s at fault here, but we believe the long cage and wide knuckle do increase the chances of damage. As a counterpoint though, there are more Eagle equipped bikes than ever before out there on the trails, so incidences of failures will always increase in line with overall use.

Now for the positives. Shifting is excellent. Yes, it has a slightly heavier action than the top end drivetrains, but go for an easier gear under load as the gradient steepens and NX will shift accurately and quietly without protest. Of course you have to make sure everything is set-up precisely – particularly the B-tension adjustment – but it’s no more sensitive than any other Eagle drivetrain in that respect. Equally, the slightly narrower gear range didn’t bother us. We rarely use the 10-tooth sprocket, so it was no great loss, and if you do love hammering a big gear, you can always run a bigger chainring.

Chain retention is also excellent and we haven’t dropped a single chain that we can remember, even without a guide. And wear has been minimal with only a few sprockets showing glints of bare metal while the chain has barely stretched.

The crank (we were sent the wider, burlier Descendant model that costs the same price as NX Eagle) is excellent – it’s stiff, lightweight thanks to the alloy axle, and also comes in 165mm lengths, which is good news if you’re running a super low BB.

SRAM NX Eagle need to know

• 11-50t cassette mounts on standard splined body, rather than XD driver
• Tough enough for e-bike use with specific single-change shifter
• Includes SRAM DUB fitment cranks, available in 175, 170 and 165mm lengths
• Compatible with XX1, X01 and GX Eagle components, allowing bike brands and consumers to mix-and-match parts
• Complete drivetrain saves £130 over SRAM GX Eagle

With the launch of Eagle, SRAM basically buried the front derailleur. Since then, other component brands have entered the wide-range arena with even larger sprockets and greater wingspans.

SRAM NX Eagle is the latest release and brings the total of SRAM Eagle groupsets up to four: SRAM XX1 Eagle, SRAM X01 Eagle, SRAM GX Eagle and SRAM NX Eagle.

So NX Eagle is 12-speed, right?

Yes, and that means it will play nicely with other Eagle components. Already got an Eagle drivetrain on your bike, and an old set of wheels in the shed with a standard splined (Shimano) cassette body? No problem; the new NX cassette will fit your hubs and mesh with your current shifter, mech, chain and cranks.

Bike brands will also be able to pick and mix parts from the Eagle family to meet a specific price point. Expect to see many more affordable complete bikes specced with Eagle next year as a result – SRAM’s reckons as low as £1,000.

How has SRAM cut costs?

The big saving comes from the new PG-1230 cassette. It uses similar sprockets to the GX Eagle version – in that they are individually stamped from steel – but rather than being pinned to a single alloy carrier, only the four largest rings attach to an alloy spider while the rest are separate. Assembly and fitting, therefore, is very similar to a Shimano cassette. The result is a £70 saving over the GX Eagle cassette at suggested retail prices – this being SRAM though, you can find them online much cheaper.

Is it still 10-50t?

No. This new construction means that it slides onto a standard splined cassette body. Which, in turn, means it can’t accommodate the 10-tooth high gear. So the new cassette is 11-50t with a 455 per cent range. But the fact it can fit on a regular cassette body, rather than an XD driver, will make it a much simpler upgrade for many riders.

What’s the catch?

In a word, weight. The new cassette weighs a hernia-inducing 614g. That’s 166g more than GX Eagle and 254g more than SRAM Eagle XX1, and enough to pull some freehub bodies clean off the hub if you turn your wheel upside down when it’s out of the bike! Of course that’s all extra unsprung mass on a suspension bike, which makes it doubly bad news.

Is it simple to fit?

Yes. If you’re a competent home mechanic you should have no problems installing and setting-up the NX Eagle drivetrain. The crankset will fit any DUB bottom bracket, whether BS threaded or press-fit (although you will need a Race Face/SRAM/Rotor BB tool). To install the cassette you just need to match up the widest splines and make sure the rings are facing the right way with a spacer between the separate sprockets. The 11t only just locates on the end of the splines, but seems to be secure enough when you tighten the lockring with a standard cassette tool. The drivetrain comes with a b-tension guide tool to simplify that adjustment and there’s a decent cable and housing to ensure slick shifting.

Verdict

It's easy to focus on the extra weight of NX Eagle and lose sight of the big picture. Yes, there's a penalty to be paid for running that heavy cassette on a suspension bike, but stand back and take in the additional gear range, precise shifting and affordable price and it's clear that NX Eagle is a ground-breaking drivetrain that will let you climb further and longer than ever before.

Details

Weight:1,957g Includes:Shifter, cassette, chain, cranks, r-mech, B-tension tool Contact:sram.com Cassette:614g Rear mech:341g Shifter (exc. clmap):112g SRAM Descnedant crank 170mm 32T:640g