Helping Find the Right Drivetrain for You.

Since the advent of the grip shifter in the late 1980s, SRAM has been known for their innovation in mountain bike components. While their product line is in constant evolution, their commitment to performance, durability, and usability remains the same. SRAMs current crop of MTB components provides industry leading performance for all riders, with options for the race-day podium or Sunday park laps. Not only does this American-based company offer a groupset for every discipline and price point, they also maintain cross-compatibly between each, allowing riders to mix-n-match to fine tune their drivetrain to their specific needs and budget. This guide is intended to outline the differences between each groupset to help you make an informed decision on which SRAM MTB groupset is right for you.

The 1x Revolution

SRAM changed the game when they pioneered 1x drivetrain (pronounced “one-by”) for many disciplines of riding. By shifting the entire gear range to the cassette, leaving just a single chainring in the front has drastically changed mountain biking. Benefits of 1x drivetrains include a simpler shifting pattern, less drivetrain noise, reduced weight, cleaner handlebar setup and fewer wear parts compared to double- or triple-chainring drivetrain. This configuration has also been widely accepted in the industry, with many enduro and trail bikes being made 1x specific, without even having an option to install a front derailleur.

SRAM’s first 1x drivetrain was paired to an 11-speed cassette ranging from 10-42T. This cassette required the development of a new freehub body standard called XD which allowed space for a 10-tooth cog, where the smallest you could achieve on a standard freehub body was an 11-tooth cog. Luckily, SRAM’s latest 12-speed Eagle drivetrains utilize this same XD freehub body. The XD standard is used on all SRAM MTB drivetrains except for NX and below (these use traditional Shimano HG splined freehub bodies). By increasing the gear range to 500%, Eagle offers the overall gear range of a typical triple chainring drivetrain with the simplicity of a 1x setup.

By torture testing their 1x drivetrains over millions of trail miles, SRAM Eagle groups continue to redefine what they believe to be the ultimate 1x drivetrain. More than simply adding an extra cog, Eagle has made improvements to increase chain life along with chainring and cassette wear. Top end SRAM Eagle components are said to last up to 4x longer than the previous generation, resulting in less money over time.

Glossary of Features & Tech

  • Eagle - the moniker given to SRAM's 1x12sp groups.
  • AXS - the wireless (no cables) electronic versions of their drivetrains.
  • DUB - SRAM's latest spindle size (28.99mm) and bottom brackets designed to create compatibility with all major standards of BB shells and deliver much longer bearing life.

SHIFTER

  • X-Actuation - keeps your shifts consistent no matter where your at on your cassette.
  • Zero Loss - a technology that eliminates free movement of your shift levers to make your shifts precise and instantaneous.
  • MatchMaker X - a clamp system designed to mount your brakes, shifters, and remotes with a single clamp on each side of your handlebar. 

CASSETTE/FREEHUB

  • XD Driver Body- a freehub driver standard introduced to allow 10-50t cassettes for a wider gear range.
  • X-Dome - a process where 9 of the 10 cogs on a cassette are machined from a single block of billet steal creating a lightweight, precise, and strong cassette.
  • X-Glide - increases chain retention on larger cogs and maintains quick a precise shifting throughout the cassette.
  • X-Sync- specially designed tooth profiles to ensure chain engagement while allowing mud and debris to clear easily.
  • Full Pin - allows SRAM to create similar cassettes to their X-Dome cassettes with a significant reduction in cost by using stamped cogs and pins.
  • PowerGlide - optimised tooth profile and shift ramp design for quick and positive index shifting.

CHAIN/CHAINRING

  • XD Driver Body- a freehub driver standard introduced to allow 10-50t cassettes for a wider gear range.
  • X-Dome - a process where 9 of the 10 cogs on a cassette are machined from a single block of billet steal creating a lightweight, precise, and strong cassette.
  • X-Glide - increases chain retention on larger cogs and maintains quick a precise shifting throughout the cassette.
  • X-Sync - specially designed tooth profiles to ensure chain engagement while allowing mud and debris to clear easily.
  • Hard Chrome - a finishing process for inner links and rollers that increases the chains resistance to wear.
  • PowerLock - Quick connect links that make installing your chain easy.
  • FlowLink - Ultra-smooth chain inner-plates without square edges reduces friction and wear while maintaining solid engagement.

DERAILLEUR

  • Roller Bearing Clutch - eliminates derailleur bounce and chain slap without sacrificing precesion.
  • X-Horizon - technology moves the derailleur along a “horizontal parallelogram” to keep the chain gap consistent between all 12 gears. This eliminates ghost shifting, leaving you with fast, smooth and precise shifts every time.
  • X-Actuation - keeps your shifts consistent no matter where your at on your cassette.
  • Cage Lock - holds the cage forward to make wheel removal and installation faster and simpler.

AXS Wireless Drivetrains

AXS is SRAM’s latest innovation in drivetrain technologies. SRAM AXS (pronounced “access”) is not only electronic, but also wireless. This means the drivetrain does not actuate with cables or wires, but instead using a wireless communication protocol to speak to the derailleur and dropper seatpost. Being wireless significantly reduces the clutter and headache of cables. This also allows for more customization through SRAM’s AXS phone app. You can tune your drivetrain or reprogram what the shifter buttons do with a simple a few clicks on your smartphone.

All this tech does come with a hefty price tag and a few concerns such as durability, precision and having to charge the batteries. We’ve spent plenty of time with these groups and they’ve proven tough, reliable, and incredibly intuitive. Also, the batteries last surprisingly long between charges and even have indicators to keep you from being caught unaware. AXS is compatible with all the other Eagle drivetrains, so you can just upgrade the shifter and rear derailleur to modernize your existing bike. Plus, you can shave a few grams by eliminating the clutter of cables and housing. If you’re all about the cutting-edge tech and the look of an ultra-clean cockpit, then the AXS groups are a perfect fit.

SRAM XX1 Eagle

XX1 Eagle is the pinnacle of SRAM’s 12-speed groupsets. Engineered from the strongest and lightest materials, XX1 Eagle is designed to be the most efficient and precise drivetrain in the Eagle lineup. There’s no sacrifice in durability for weight savings, as XX1 Eagle can take the abuse of even the most challenging world-class courses. This is the top tier drivetrain with all the bells and whistles: mechanical and AXS wireless options, lightweight, Match Maker X shifter pods, X-Horizon technology and SRAM’s latest Type 3 roller bearing clutch. XX1 Eagle is perfect for the racer or the rider who demands the best and wants to make the most of every watt put down through the pedals.

XX1 Eagle Specs & Features:

  • Highest tier group
    • Available as mechanical or AXS wireless
  • Lightest materials without sacrificing strength
  • Best machining, tolerances and utilizing the most efficient coatings
  • Matchmaker compatible and adjustable shifter with ZERO LOSS tech
  • 10-50t cassette machined from a single block of billet steel
  • Recommended Rider: XC racers and riders looking to shave every second

Component Weights

  XX1 Eagle XX1 AXS
Crankset (175mm/32t) 422g 422g
Rear Derailluer 265g 375g
Cassette 360g 360g
Trigger Shifter 124g 70g
Chain 260g 260g
Total   1431g 1487g

SRAM X01 Eagle

SRAM X01 Eagle is the best choice for the enduro rider who needs a hard-wearing drivetrain but isn’t overly concerned with weight. While it retains much of the performance of XX1 Eagle, X01 comes with some material changes to improve durability and decrease price. For example, X01 is built with a foam-core carbon crankset instead of the fully hollow XX1 crankarms. Production changes like these add up to a very minor weight penalty of around 60 grams over XX1 Eagle while maintaining all the same features and technologies including wireless electronic option. X01 Eagle is the best choices for riders seeking top-end 12-spd performance, but who are willing to sacrifice a few grams to save a few dollars.

X01 Specs & Features:

  • The tougher sibling to XX1 with minimal weight gain
    • Available as mechanical or AXS wireless
  • More focus on strength over ultimate gram savings
  • Matchmaker X compatible and adjustable shifter with ZERO LOSS tech
  • 10-50t cassette machined from a single block of billet steel
  • Recommended Rider: Leaning towards the enduro end of the spectrum

Component Weights

  X01 Eagle X01 AXS
Crankset (175mm/32t) 471g 471g
Rear Derailleur 276g 388g
Cassette 354g 354g
Trigger Shifter 124g 71g
Chain 260g 260g
Total 1485g 1544g

SRAM GX Eagle

GX gets straight to business. No carbon fiber parts, no claims at being “lightweight”. Just a simple, reliable 1x12 drivetrain that provides the gear range you want at more attainable price point. Still benefitting from crisp Zero Loss shifts along a 10-50T cassette, the primary difference between GX Eagle and its fancier siblings comes down to materials and machining. Without focusing on shaving grams, the machining processes are dramatically simplified, ultimately driving down costs. The most significant weight gain is found in the stamped and pinned cassette at 450g, but this is competitive with cassettes like the Shimano XT. Also, because GX still uses the XD freehub body, you could always mix-n-match and run a higher-end cassette on your GX drivetrain to lighten the overall weight.

GX Eagle Specs & Features:

  • Mid-tier group
  • Matchmaker X compatible with ZERO LOSS tech
  • XD driver
  • 10-50t pinned cassette
  • Recommended Rider: focus on balance of performance and price

Components Weights

Crankset 621g
Rear Derailleur 290g
Cassette 448g
Trigger Shifter 122g
Chain 262g
Total 1743g

*weights do not include cables and housings

NX Eagle

NX is the perfect drivetrain for bringing new life to your favorite bike. The primary difference with the NX groupset is the cassette. The 11-50T cassette does not use SRAMs propriety XD freehub body, instead utilizing the traditional slide-on Shimano HG style. This is great for those looking for the range of a 1x12 drivetrain but who cannot fit a XD freehub body to their rear hub. While you lose some of the top-end range compared to 10-50T, this makes the cassette much more affordable and makes it possible to go 1×12 to almost any bike!

NX Eagle Specs & Features:

  • Entry-level group
  • 11-50t cassette stamped steel pinned cassette
    • Compatible with HyperGlide splined freehub (Shimano HG)
  • Shifter is not MatchMaker compatible but has ZERO LOSS tech
  • Recommended Rider: looking to shred on a limited budget

Component Weights

Crankset (175mm/32t) 698g
Rear Derailleur 340g
Cassette 612g
Trigger Shifter 111g
Chain 271g
Total 2032g

 

Downhill Groups – X01 DH & GX DH

X01 DH is the downhill racer’s choice. When fractions of a second count, SRAM knows you need complete confidence in your drivetrain. With feedback from World Cup pros, SRAM developed a 7-speed X01 group worthy of any podium. Downhill don’t require the same gear range as typical trail riding, which is why this option uses a 7-speed XD cassette. The X01 DH cassette has a 10-24T gear range and an integrated spoke guard to prevent the chain from bouncing into the spokes. The compact range also allows for a shorter derailleur cage, preventing the derailleur from getting snagged on obstacles.

Knowing that downhill rigs are often focused more on durability than weight savings, SRAM also offers a GX version of this DH line. Like the standard GX groupset the primary difference lies in less expensive materials and changes in machining processes. The GX DH 7-speed cassette is not XD driver-specific but mounts to a standard 8/9/10/11 speed freehub. This saves the cost of having to purchase an aftermarket XD driver for your wheels, but also reduce the gear range to 11-24t.

DH Groups Specs & Features

  • X01 DH shifter utilizes ZERO LOSS technology for instantaneous shifts
    • MatchMaker X compatible and multi-adjustable
  • GX DH shifter doesn't use ZERO LOSS technology and doesn't inlude clamp (must purchase separately)
  • 7-sp cassettes focused on DH needs and compatible with all 11-sp chains
    • X01 utilizes XD driver (10-24t) and GX utilizes spline driver (11-25t)
  • DUB cranksets increase seal life, reduce weight, and improve strength
    • GX DH group is intended to be matched with Descendant or GX cranks

Component Weights

  GX DH X01 DH
Crankset (175mm/32t) 717g (Descendant Alloy) 533g
Rear Derailleur 296g 257g
Cassette 224g 136g
Trigger Shifter  122g 125g
Chain  262g 260g
Total 1621g 1311g