SRAM XX – New Details and Specs

sram xx crankset and bottom bracket mountain bike 2x10 drivetrain

SRAM officially debuted their XX minisite today, with tons of photos and more details than you can read in one sitting…unless, of course, you’re like us and love this stuff.

DEVELOPMENT PROTOTYPES:

The first things they cover are some of the development sketches and prototypes, like these (click to enlarge):

sram-xx-9 sram-xx-5 sram-xx-6sram-xx-8

From left to right:

  • XX front derailleur prototype model
  • Early stage 8-speed machined out cassette
  • Shifter lever concept sketches
  • Late-stage hydraulic lockout button prototype

Hit ‘more’ for lots more pics and details, or check our previous post for more tech specs…

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This is just about what the finished product looks like, but as you can see from below, they toyed with a more traditional lockout lever before upping the ante with the hydraulic button.

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sram-xx-7

PERFORMANCE DETAILS:

SRAM claims one of the biggest advantages and improvements of the XX system comes from the front shifting.  They took an old patent that covered a certain ratio of small/big chainring combos (3:2 ratio) and combined it with specially designed ramps, pins and teeth to create rings that really work throughout the entire rotation to shift smoothly.

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Here’s how:  Each ring has four pick-up and four release points.  They’re positioned such that they keep the chain engaged on the maximum number of teeth on both rings for as long as possible during the shift.  This allows you to shift under power, and provides for a smooth transition.  The image below shows the shift points on the XX rings versus traditional rings:

sram-xx-1

On the back of the bike, the machined out X-Dome cassette takes a whopping nine hours each to manufacture.  The open design helps shed mud and dirt, and it’s an objet de arte.

sram xx cassette x-dome mountain bike component 10 speed

The middle eight gears are machined from a solid block of billet steel.  The little and big gears are aluminum and are replaceable.

sram-xx-cassette-side

Another big difference is the move from SRAM’s 1:1 movement between derailleurs and shifters to the Exact Actuation used on their road groups.  Now, the effort and movement on the shifter is exactly the same regardless of what gear you’re in, and it pulls the same amount for each gear…3mm.

sram-xx-shifterpod

Another new feature is a reach-adjustable thumb lever.  The trigger has also been shortened, and the shifters mount using the new Matchmaker X mounting bracket.

sram xx shifter levers with matchmaker x mounting bracket mountain bike 2x10 drivetrain component group

sram xx rear derailleur mountain bike component

SUSPENSION:

RockShox has also upgraded several of their forks with the XX moniker and some tech improvements.

sram rockshox sid world cup xx mountain bike suspension forksram rockshox sid world cup xx mountain bike suspension fork

SID, Reba and Revelation get the XX treatment, which boils down to three things:  XX Motion Control gives the forks Dual Flow rebound (separate controls for beginning and ending stroke rebound), tunable Low Speed compression and of course, the all-new hydraulic X-Loc lockout button.

Read it all at sram.com/xx, and check our previous post for a tech run down of all the components.

Comments

Marshall Hance - 06/10/09 - 5:08pm

Lot’s of cool technology, buts so upsetting that 10speed chains only last about 3-4 hours of mountain bike racing use and are $60 to replace.

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