In case you missed the news last year, it seems SRAM isn't a big fan of the front mech and wants to see it, and the constraints it puts on bike design, gone.
Last year it launched its top tier 1x12 XX1 and X01 Eagle drivetrains in a bid to finally wipe this complex bit of kit out. The problem was the price ruled these out for a lot of people.
Fast forward 12 months and SRAM's battle with the front mech continues on. This time, though, it has managed to halve the cost of the latest drivetrain but still deliver a huge gear range and the same dozen gears. So how has SRAM done it?
Same same but different
GX Eagle, just like its pricier counterparts, has a 500 percent gear range, using an almost identical 12-speed 10-50T cassette to deliver it. Crucially, though – and the thing that is likely to matter to general punters and SRAM’s OE customers alike – it’s a hell of a lot cheaper.
For those familiar with SRAM’s 1x11 systems and their hierarchy, (XX1, X01, X1, GX and NX) it seems Eagle has trickled down a little further than expected, missing out on any kind of X1 offering whatsoever.
Why? Well, as it transpires it’s down to SRAM’s OE customers who specifically wanted a much more cost-effective 1x12 alternative for the type and price of bikes where they thought it’d really make a difference. GX Eagle seemed like the logical next step.
While there’s a significant reduction in price, overall weight isn’t as far off the likes of the pricier X01 Eagle as you might have thought, with just a 14 percent overall increase.
The biggest talking point when the Eagle drivetrain launched last year was, as you’d expect, the 12-speed cassette which includes the whopping 50T sprocket. In appearance, the GX offering doesn’t look all that different.
Of course, on closer inspection it's clear things aren’t quite the same. At 450g it’s 90g heavier than the X01 equivalent and put together in a far more cost-effective way.
To help keep pricing down, the new GX cassette uses stainless steel pins to hold the 11 stamped steel cogs and single 50T aluminium cog together (the XX1 and X01 Eagle cassettes have the first 11 cogs machined from a single piece of steel which accounts for the far higher price). The range on offer is identical though, courtesy of that 10-50T spread.
Steps between gears average out at 18 percent (the biggest is actually 20 percent) which might sound quite big but in practice things don’t feel as gappy as expected.
At 290g, the new GX Eagle rear mech weighs just 14g more than the X01 equivalent but costs almost half as much. It uses the same, 1x specific X-Horizon design and larger (than the 11-speed) 14T ‘Eagle’, X-Sync 2 lower jockey wheel to help shifting up and down the wide range cassette.
You also get the same Type 3 roller bearing clutch mechanism to help keep the chain taut as you clatter over rough ground.
The biggest differences with the GX mech is that SRAM have used a lower spec aluminium to produce it (and absolutely no carbon as used on the XX1 Eagle mech), a steel rather than titanium spring, heavier hardware and lower grade bearings, all of which have enabled SRAM to keep it priced so competitively.
Keeping things turning
Unsurprisingly, there’s not a hint of carbon used in the all new GX crank arms. Instead you get 7000 series, forged aluminium numbers built to take SRAM’s direct mount X-Sync 2 chainring in 30, 32 or 34T sizes (more on the rings in a minute).
Just like the other Eagle cranksets, you get the choice of a 24 or 30mm bottom bracket axle but, GX does offer three rather than just two crank lengths which include 165mm, 170mm and 175mm options. Bottom bracket offerings include GXP, Press Fit GXP, Press Fit 30 and BB30 meaning all bikes are pretty much covered.
Thanks to the familiar three-bolt direct mounting system, the latest X-Sync 2 chainring attaches neatly to the crank arms and is a doddle to switch should you want to mess about with ring size.
In this case the ring is cold-forged aluminium and gets SRAM’s most up to date teeth profiling. The ‘shark fin’ silhouette and additional shaping at the base of the teeth is claimed to help shed mud and trail litter more effectively than the previous X-Sync design which could at times collect quite a bit of crud over the course of a ride. This also helps with a reduction in chain noise and retention, smoothing out how the two interact together while in motion.
SRAM also claims that the X-Sync 2 tooth profile also helps with how load is distributed when power is applied through the chain, allowing the chain to engage with more teeth. The result is improved wear on the chain and chainring in the long term.
What you won’t see on the shop floor, or at least according to SRAM, you shouldn’t see, are bikes with different brands of cranks and chainrings on as they consider the Eagle drivetrain to be a complete system and, with a non-SRAM crankset bolting on, it simply won’t work as effectively. Whether we see bike brands deviating from this only time will tell.
Connecting the dots
Of course, none of this lot would work if not for the chain. And what a bit of kit the GX Eagle chain is. To help reduce costs, this particular specimen uses solid rather than hollow pins and has a hard chrome coating as opposed to the ti-nitrate treatment the more expensive chains further up the Eagle range receive.
There remain some similarities, though. Inner chain plates get chamfered to help reduce friction, noise and SRAM claims to produce a better engagement on the ring and cassette. This in turn then helps wear life, bolstering durability.
On top of that, the design allows the chain to be narrower which helps when tackling more extreme chainlines as you shift through to the highest or lowest sprockets on the cassette.
SRAM explained to achieve such a feat, it takes around 37 stamping processes to create the chain. Impressive considering the price tag and the fact that it’s a mere 20g heavier than XX1 and X01 equivalents at 270g. And of course you still get the ever so handy PowerLock connecting link which helps remove a great chunk of faff when removing/replacing the chain.
Trickling it down
Considering the GX Eagle shifter costs just a fraction of its XX1 and X01 peers, it’s seriously impressive to see that it’s actually friendlier on the scales than the X01 number, and the same as the XX1 shifter, at just 122g.
Part of that does come down to the fact that it’s made with a plastic body and the main shifter paddle is aluminium. There’s also a bushing rather than smoother bearing used which is noticeable on the trail, but soon forgotten about. It does inherit the same X-Actuation and Zero Loss technology though, which in short promises to deliver crisp, accurate shifts up and down the cassette. Tidy.
SRAM GX Eagle pricing
Now for the important pricing….
- Cassette - £170/$195
- Rear mech - £95/$110
- Crankset - £105/$120 (GXP) £125/$140 (BB30)
- Shifter - £30/$40
- Chain - £25/$30
SRAM GX Eagle initial ride impressions
Did the latest and cheapest 1x12 drivetrain deliver on everything SRAM had promised? Well, to be honest, two really wet rides in the Forest of Dean maybe doesn’t give us quite enough to go on for a full, in-depth analysis.
My two days of riding in some really quite unpleasant conditions did shed some light on how it’ll feel once totally coated in grime, grit and slime, though. And to be fair to the SRAM guys, the GX Eagle was hard to fault during our short test rides, even in the sloppy grinding paste conditions we were subjected to.
Shifting feels comparable to that of the more expensive Eagle transmissions thanks to the positive click SRAM has become known for, though not quite as light to the touch. That’s no major worry, though, and soon forgotten about when you’re hacking around the hillside.
More impressive is the lack of noise and just how smooth things remain even when shifting up into the bigger sprockets where the chain angle becomes more extreme. Even when transferring the chain into the monster 50T cog, there is very little grumbling going on and I never felt like I had to totally ease off the power because things didn’t feel quite right. It’s impressive stuff.
I had absolutely zero issues with keeping my chain on, too, which is also a plus. Even with the bikes properly slathered in thick gloopy mud (including the crankset and chainring) there was no hint of the chain lifting off the ring and it managed to stay put even on the some of the more awkward rocky trails we tackled.
Understandably, I can’t comment on longterm durability just yet. While I’ve had no issues with the X01 Eagle I’ve had on my bike now for about a year, I’m keen to put the GX equivalent through the same schedule and see how it fairs. Stay tuned for the full review in the not too distant future.
SRAM GX Eagle early verdict
If you’re looking to expand your gear range without adding a front mech or totally emptying your bank account in the process, GX Eagle is well worth a look.