SRAM XX1 Eleven Speed Drivetrain - First Look

SRAM’s XX1 eleven-speed cassette and single-chainring drivetain has been whispered about for almost a year, but few have actually seen a complete one in the flesh. The heart of the new XX1 ensemble is an 11-cog cassette that uses a new freehub interface developed at DT Swiss that allows for a tiny, ten-tooth cog on the small end, while sporting a mammoth, 42-tooth aluminum cog on the other. Driving the cassette is a single-ring crankset with carbon fiber arms and a tiny four-bolt aluminum spider. The XX1 X-Horizon rear derailleur uses SRAM’s recently released type II roller-bearing clutch for maximum chain control, with two additional features: A lever that locks the pulley cage forward to facilitate wheel changes, and an offset cage pivot that keeps the upper guide pulley closer to the small cogs as the derailleur moves across the cassette. XX1 is a completely new system, with its own chain and dedicated shifter (trigger or Gripshift), and while it may appear to be a radical change among the sport’s more conservative members, its actual release represents the logical evolution of a grassroots single-ring drivetrain movement that began in earnest a decade earlier. In fact, the question that most riders will ask after riding XX1 will be, “Why has it taken so long for the industry to figure this out?”


Why Bother With 1 x 11?

SRAM’s XX1 solves three once-insurmountable problems that nagged single-chainring drivetrains - with 11 perfectly spaced gear ratios that match or exceed the range of present three-by or two-by drivetrains; with the introduction of the type-II derailleur’s one-way clutch that controls chain slack to prevent tossing the chain due to rough terrain; and with carefully engineered tooth profiles on the chainring that ensure the chain will engage the sprocket and remain secure at the wide input and output angles inherent to single-ring drivetrains as the system is shifted across the cassette. In addition, SRAM incorporates a quick-change chainring option for the XX1 crankset that allows XX1’s overall gearing to be easily modified without removing the crankarms.

Potential Benefits of XX1

By eliminating the front derailleur, XX1 gives frame designers extra space in the crowded bottom bracket area to enlarge tire clearance and to shorten the chain stays. For 29er designers, this is a huge benefit. For trail riders, the elimination of the left shifter supercharges gear changes by allocating the task to one hand and one part of the brain – and it makes the left side of the handlebar a logical place for a stand-alone remote dropper-post control. For vanguard suspension designers, the empty space on the left handlebar can be used for remote damping or lockout controls, which would dramatically uncomplicate bikes like the Scott Genius or Cannondale Jekyll. For most of us, however, XX1 promises to boost performance by giving us the correct gear we want with one shifter. Eliminating the classic double or triple shift, just to get to the one gear we need, is reason enough for a 1 by 11 drivetrain. Reducing weight and simplifying the drivetrain is icing on the cake. The following is SRAM’s official XX1 press release - RC

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SRAM XX1 One by Eleven Drivetrain is Official

SRAM XX1 was built with a dedicated 1X drivetrain philosophy - making it simpler, lighter and more durable than any other. No matter where you ride, no matter what you’re up against: SRAM XX1. Unstoppable.

Single-Minded Pursuit

Driven by a cutting-edge, single-ring carbon crank and seamless component integration, SRAM 1X drivetrain delivers flawless chain management and faster, more precise shifting. But the relationship between XX1 components goes far beyond fitment. From the X-HORIZON rear derailleur with TYPE 2 technology to the super wide range 11-speed 10-42T cassette, each component is designed to function synergistically with the others, achieving what no other 1X drivetrain has before. (Available October 2012.)


XX1 Crankset

X-SYNC - A CNC-machined, “wide tooth, narrow tooth” pattern is repeated around the entire chainring, perfectly mirroring the chain’s inner and outer links for maximum control.

GXP - The GXP bottom bracket's Gutter Seal design cuts friction, durability and weight - improving both feel and performance.

King of the Ring:
Developed for maximum chain control, each tooth’s thickness is precisely CNC-machined to support the chain’s inner and outer links perfectly. Six available chain rings (28, 30, 32, 34, 36, 38 ) allow you to tune your gear range to match your terrain, wheel size and riding style. Each X-SYNC chain ring fits a single, universal spider - allowing you to change rings without removing the light-weight carbon crank arm.


• New tooth profile alternates thickness by inner and outer links, providing maximum chain control
• Carbon arms with forged aluminum spider
• CNC-machined rings (28, 30, 32, 34, 36,38 )
• New spider design allows for easier ring changes
• Wide/narrow Q factor cranks for BB30 and GXP
• Weight: 650 grams with BB (approx.)
• MSRP - TBA


X-HORIZON Rear Derailleur


X-ACTUATION - Developed specifically for the SRAM 1X11 drivetrain, X-ACTUATION keeps shifting sharp and consistent across the entire 10-42T cassette.

X-SYNC - A “wide tooth/narrow tooth” pattern is repeated around the pulley wheel, perfectly mirroring the chain’s inner and outer links for maximum control.

CAGE LOCK - With Cage Lock, wheel removal and installation—as well as chain installation— becomes faster and simpler. Just push the cage forward to create slack and then lock it into place.

ROLLER BEARING CLUTCH - Roller Bearing Clutch technology eliminates derailleur bounce and chain slap without sacrificing precision.


With its “horizontal parallelogram” design and pulley offset, X-HORIZON keeps the chain gap constant across all 11 gears, providing fast, precise shifts. By limiting all movement to the horizontal axis, this design is faster, reduces shift force and eliminates ghost shifting. ROLLER BEARING CLUTCH technology reduces bounce and chain slap. CAGE LOCK technology makes wheel removal and installation easier than ever before. Paired with the XX1 shifter, the X-HORIZON RD forms the backbone of X-ACTUATION technology for unbelievably smooth shifting action.

• Large upper pulley offset automatically adjusts chain gap
• Straight parallelogram design with horizontal movement reduces shift force and improves drivetrain performance
• 12T X-SYNC pulley wheels
• TYPE 2 technologies: ROLLER BEARING CLUTCH and CAGE LOCK
• New silent pulley tooth design • Weight: 220 grams (approx.)
• MSRP - TBA

This rear derailleur’s “horizontal parallelogram” design limits all movement to the horizontal axis, which makes ghost shifting impossible while also reducing shift force. For quicker, more exact shifting, the large upper pulley offset design maintains a constant chain gap across all gears.


XX1 CASSETTE


First of its Kind:
Ranging from 10- to 42-teeth, the 11-speed X-DOME delivers an incredibly wide gear range while maintaining even, optimized steps. The single-unit cassette combines with the XD driver body for a superior connection to the wheel.

• 11-speeds (10 - 12 - 14 - 16 - 18 - 21 - 24 - 28 - 32 - 36 - 42)
• Bearing design and ratchet mechanism steadied by XD driver body
• Creates more stable hub connection
• Gear steps optimized across entire range
• Wheels equipped for XD driver body available from SRAM and DT Swiss
• XD driver body is 6-8g lighter
• Weight: 260 grams
• MSRP - TBA

X-DOME - X-DOME technology creates an incredibly lightweight, precise and strong cassette. The open design aids in mud clearance, giving you cleaner shifting performance and longer component life.

XD DRIVER BODY - XD is a new cassette driver body design that allows the use of a 10 tooth small cog and provides an improved interface with the cassette.


XX1 GRIPSHIFT - TRIGGER SHIFTER


Trigger Shifter:
• SRAM 1X11 X-ACTUATION for precise and dependable 11-speed performance
• Multi-adjustable trigger shifter
• MatchMaker X compatible
• Carbon cover and adjustable carbon pull lever
• Full Gore Ride-On cable system
• MSRP - TBA

X-ACTUATION - Developed specifically for the SRAM 1X11 drivetrain, X-ACTUATION keeps shifting sharp and consistent across the entire 10-42T cassette.


GripShift:
• SRAM 1X11 X-ACTUATION for precise and dependable 11-speed performance
• SPEED METAL shift indexing
• ROLLING THUNDER ball bearing technology
• JAWS lock-on grip technology Carbon cover Full Gore Ride-On cable system
• MSRP - TBA

ROLLING THUNDER - Three rows of ball bearings provide zero friction or play - reducing the force needed to shift and promoting long-term performance under all weather conditions.

SPEED METAL - Full metal, 11-speed indexing keeps shifting crisp and precise
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XX1 CHAIN


Powerful Connections:
The XX1 chain represents the latest breakthrough in a long line of precise, light-weight chains from SRAM. It’s designed to deliver the greatest strength and reliability to a drivetrain that doesn’t have to make compromises for front shifts.

• New 1X11 XX1 specific chain
• Designed for maximum strength and wear resistance
• Proprietary link finish provides improved life span
• 11-speed power lock
• MSRP - TBA


(Available October 2012.)
www.sram.com

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