SRAM GX Eagle groupset has been flawless. Extra range proved a welcome surprise, plus it’s smoother pedalling than rivals, silent with positive shifting.
Editor’s Choice 2020
Earlier this year SRAM’s workhorse groupset, GX Eagle, got a slick new revamp with a gunmetal finish as well as functional updates designed to improve durability. Not only that, it got a new, broader wingspan, thanks to the 10-52t cassette. What this means is you can now spin on slopes where you would previously have grinded up, and ride up hills you would have normally walked. Shifting is solid yet speedy, with less pinginess than its Japanese rival, and best of all, drivetrain life seems better than ever thanks to clever coatings.
Designed in Germany, SRAM GX Eagle groupset is SRAM’s most popular MTB drivetrain and a fixture on scores of complete bikes. It’s been updated for 2021 with a new finish and a more sculpted design, but the headline change is increased range, thanks to a new cassette with a huge, dinner-plate-sized, 52 tooth sprocket.
Climbing from a tiny 10t cog, the cassette uses a pinned cluster of steel cogs up to 42 teeth with an aluminium big ring. It fits a standard XD driver body, but the rear mech design has changed in order to smoothly wrap the biggest gear (it actually shares similarities with the wireless SRAM AXS drivetrain). The mech also gets subtle but harder to spot improvements like a sturdier cage, better hardware materials and a stiffer main pivot. Plus, it’s also backwards-compatible with older 10-50t cassettes.
The snappy 12-speed GX shifter pulls a derailleur using a stabilising clutch that combines with the sophisticated front chainring for near flawless chain retention. SRAM’s X-Sync II chainring tooth profiles are superior to rivals, so, as well as a very fluid, friction-reducing, mesh with the internally rounded Eagle chain plates, I didn’t drop the chain once over months of testing that included full-on Alpine DH tracks. The brand’s cage lock mechanism keeps it out of the way when removing wheels and is something I really miss when switching back to a Shimano drivetrain.
In terms of set-up, B-Tension (distance between chain and cassette) is critical, but there’s a new (easy-to-use) widget for perfect alignment, and the shifting on my bike stayed rock solid throughout the test. I chose stubby 165mm cranks (only available in alloy) to maximise clearance on a long travel Specialized Enduro, and these are super stiff and solid, even running broad flat pedals that exert tons of leverage when cranking (or even landing) hard.
Gear changes have been light and crispy since day one, and the GX drivetrain simply hasn’t skipped a beat. In fact the whole system has not required any cable tensioning or adjustment whatsoever, and I’ve also used SRAM’s package on many other test bikes all with zero issues.
A common complaint I’ve read elsewhere is the ten-tooth jump to the biggest cog potentially being too big. I’ll admit some initial scepticism too, but it’s totally not an issue in the real world. The shift is seamless and fast enough both ways (marginally slower downwards) and I never experienced a sense of too much transition at once. I’m pretty fit, so I did question whether I actually needed such an easy gear. But, once I dropped the machismo, the extra two teeth over the older 50t Eagle cassette was both noticeable and welcome. On steeper climbs it allowed me to spin where I’d previously walk, and this gives options to mix up pedalling with pushing and use different muscle groups on long, brutal climbs. This factor alone can be as good as rest on a big day out or enduro race.
One other thing worth mentioning is SRAM’s latest cages and oversized, directional, jockey wheels address a rare previous Eagle issue where chains could jam between the lower jockey and cage plates and destroy the cage under load – from our experience this simply isn’t a thing any more.
SRAM has made all the right compromises here. The cassette is undoubtedly expensive, but the wear life of the overall system is great, and details like a less CNC’d front chainring, pinned X-Dome cassette and cheaper finish and heavier link pins on the chain add weight and reduce durability (although only fractionally), but don’t impact smoothness and function. This is to the point I’d struggle to tell the difference between top tier X01 or XX1 kit in a blind test, and that’s a major win when GX costs nearly half the price.
SRAM GX Eagle groupset individual prices and (claimed) weights
Alloy DUB chainset £134 / Weight: 620g
Carbon DUB chainset £260 / Weight: 555g
Rear Mech £110 / Weight: 299g
Shifter £36 / Weight: 122g
Cassette £196 / Weight: 452g
Chain £25 / Weight: 244g (114links)