MEGA Range: SRAM Eagle Goes to 52 Teeth 12

SRAM has long lead the way in 1X drivetrains, and their 12-speed cassettes are now offered with a new 52-tooth big cog. The rest of the cassette remains the same with tight gaps before going to a big 10-tooth jump on the last shift to the massive climbing cog. The 2-tooth increase from the previous 50-tooth version isn't so large as to encourage a larger front chainring – though there's nothing stopping you from doing so if you're a stronger rider – but instead it gives more of a bailout gear paired with your current chainring size.

Updates to the Eagle derailleur cage structural integrity, pulley wheel offset, and a lengthened parallelogram make the move to 52-teeth possible. As a result, SRAM doesn't suggest using an existing V1 mechanical GX, X01, or XX1 Eagle derailleur with the new expanded range cassettes. In fact, they say you'll "encounter a more labored, less precise shift experience" if you try it. The new derailleurs will work with either size cassette, though, and 10 to 50-tooth cassettes will continue to be made. They aren't "going anywhere soon," says SRAM. However, if you are a wireless Eagle AXS user, you will be able to use the new 52-tooth cassette without any issues since the AXS derailleur was designed to be forward compatible.

SRAM Eagle derailleurs are particularly sensitive to improper chain length and b-tension setup. Luckily a new unified chain gap tool makes things easier. Just ensure things are adjusted at sag in second gear. This tool replaces all other Eagle chain gap tools across both cassette sizes, and helps ensure better precision in your b-tension adjustment.

There's a wide range of colors across the updated Eagle ecosystem as well, including black, gold, rainbow, and an all-new copper that looks bangin'.

GX

"Day in, day out, this is the Eagle ecosystem at its best. GX Eagle combines the full-featured capability of Eagle technologies, in a group that realizes the potential within every build."

X01

"X01 Eagle is the drivetrain for riders and racers who demand adaptability and versatility out of their equipment. Whether having fun, progressing skills or taking the win—X01 Eagle is designed and refined to support riders with the power of expanded capability."

XX1

"Soaring at the highest altitude of our expanded, deeper, and more capable Eagle ecosystem, XX1 Eagle is the group for top-tier race bikes and absolute dream builds. Pro level performance and compatibility with all Eagle gear ranges, the XX1 Eagle drivetrain remains incredibly quiet, intuitive, and precise."

GX Eagle Now & Then - A Visual Comparison

GX Initial Impressions

Remember when SRAM introduced the 11-speed XX1 drivetrain back in 2012? That 10 to 42-tooth cassette made waves alongside the narrow/wide chainring tooth profile that is now commonplace. Today you're basically looking at that same cassette in terms of tooth counts, but adding a massive 52-tooth cog as a 12th gear.

We've had around a month of ride time on the new GX Eagle drivetrain. Super cadence-sensitive riders may say otherwise, but we found the final big jump to be advantageous in a variety of riding scenarios – it's something you'll get used to and begin to take advantage of within a single ride. Even under lots of power, mid-turn shifts to the 52-tooth cog on properly steep uphill switchbacks, for example, are remarkably smooth.

The increase here is not so large that balance becomes an issue due to slower climbing speeds at a given cadence, but it's large enough that your legs will feel the difference in a positive way. Cruising up in the big cog, you feel grateful to be able to spin your legs. It'll still take the same amount of work to get to the top, but the ability to spin a bit easier is welcomed on the steepest portions of trail. It's also excellent on short, quick, steep ups.

In our early testing, most shifts feel a bit more refined than the GX Eagle of old. Unlike the speed of the shift in the opposite direction, however, shifting into the 42-tooth cog from the 52-tooth can be a little laggy as the chain drops down those 10 teeth. It's still quite smooth, just a hair slower to happen. The GX shifter itself has some relatively sharp-edged paddles, but it functions well.

We've had zero issues with chain retention, even without a guide.

It's still too early to make the call on durability, of course, but not much has changed here. You're still looking at an aluminum alloy big sprocket paired with a durable steel cluster that's been pinned together.

What's The Bottom Line?

When it first launched, part of what made SRAM's 1X Eagle drivetrain really stand out was its wide range, giving riders the ability to both mash on descents and spin up climbs a little bit easier. We're fans of the move to a bigger 52-tooth cog for the many climbing challenges while mountain biking – whether you're faced with a relentless fire road, steep pitches of trail, techy ups, or tricky switchback ascents.

Head over to www.sram.com for more details and pricing for the entire updated Eagle range, which is available this June.

About The Tester

Brandon Turman - Age: 34 // Years Riding: 19 // Height: 5'10" (1.78m) // Weight: 170-pounds (77.1kg)

"I like to have fun, pop off the bonus lines on the sides of the trail, get aggressive when I feel in tune with a bike, and really mash on the pedals and open it up when pointed downhill." Formerly a mechanical engineer and Pro downhill racer, Brandon brings a unique perspective to the testing game as Vital MTB's resident product guy. He has on-trail familiarity with nearly every innovation in our sport from the past several years and a really good feel for what’s what.