Single and Ready to Mingle: SRAM Shows Off CX1 at Sea Otter

SRAM’s CX1  group is singularly focused and narrow minded.

While usually deemed character flaws in most situations, these attributes are instead what make SRAM’s new cyclocross group so unique. Built on the single chainring architecture pioneered by the brand’s XX1 mountain drivetrain, CX1 borrows heavily from that group and its X01 sibling both in terms of technology and shared componentry.

Catching up with SRAM road product manager, JP McCarthy, at Sea Otter, we asked plenty of questions and subsequently did our best to keep from drooling over the feature-rich new group.

Speaking to the inspiration for the the group, McCarthy acknowledged that the group was really just “a natural progression” from their existing single-ring mounting groups. With the gearing demands of cross already clearly known—and quite a bit narrower than its mountain sister discipline, a one-by cyclocross group simply made sense. Add in the fact that the existing one-by ‘cross market was “drastically underserved,” and you have SRAM’s motivations for developing CX1.

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SRAM Road Product Manager JP McCarthy’s personal CX1-equpped race bike was on-hand at the Sea Otter Expo. Two cross seasons and 18 months of riding and still not a single dropped chain.

Built around the X-Sync chainring that debuted with the XX1 group, CX1 chainrings use a profile that is in every way identical to the existing XX1 profile—a good thing in this case. By themselves, XX1 rings account for a great deal of the chain retention benefits afforded by a dedicated one-by drivetrain. Offered in a full host of sizes from 38T to 46T in two-step increments, the Force CX-1 group affords plenty of gearing options up front.

Out back, what is essentially an X01 DH rear derailleur oversees shifting duties, albeit with some slight, but very important modifications. A built-in barrel adjuster provides easy shifting adjustment, while it’s also built around a different cable pull than it’s mountain sibling—making it compatible with both 10-and 11-speed systems—no doubt a boon for racers who already have a quiver full of 10-speed wheels.

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Old is new. While straight parallelogram rear derailleurs are nothing new, SRAM discovered that in a one-by application, the design greatly reduces unwanted side-to-side chain motion.

Employing a straight-parallelogram construction, which SRAM dubs X-Axis, the derailleur travels horizontally through the gear range, rather than vertically as well.  Chain gap is then managed via chain tension afforded by the derailleur’s clutch mechanism.  Sporting an impressive 25-tooth capacity, the CX1 rear derailleur can accommodate a wide variation among cassettes and chainrings without the need to change the chain length—meaning race-day gear changes are a rather simple undertaking.

Add to the group’s chain security a 180-gram weight savings over a 2-by Force group, and you have the makings of rather attractive package.  By removing the shifting internals from the left Force lever, the CX1 lever sheds forty grams, while the omission of the front derailleur and second chainring make up the rest of the difference.

Already seen in action in professional use, CX1 will be available to mere mortals in July.

CX1 Weights

– Force CX1 Rear Derailleur: 261 grams
– Force CX1 GXP Crank (chainring and BB cups not included): 710 grams
– Force CX1 BB30 Crank (excluding chainrings and BB): 542 grams
– Force CX1 X-Sync Chainring: 70-100 grams
– Force CX1 Left Brake Lever: 119 grams
– Force CX1 Right Shift/Brake Lever: 158 grams

2014-04-29T15:32:01-08:00