SRAM CX1 1x11 cyclocross drivetrain - First look

SRAM CX1 1x11 cyclocross drivetrain - First look

Dedicated 1x system will be lighter and simpler than current Red 22 setups

Ryan Trebon (Cannondale-Cyclocrossworld.com) and Elle Anderson (California Giant) raced at the US national cyclocross championship on SRAM's new CX1 1x11 drivetrain

James Huang/Future Publishing

James Huang

Published: January 13, 2014 at 1:41 am
Ryan Trebon (Cannondale-Cyclocrossworld.com) and Elle Anderson (California Giant) raced at the US national cyclocross championship on SRAM's new CX1 1x11 drivetrain - James Huang/Future Publishing
The new SRAM CX1 chainring mounts to the outboard position on what looks to be a standard Red 22 crankset. The teeth appear to be offset slightly inboard to yield a proper chainline - James Huang/Future Publishing
The new SRAM CX1 drivetrain will certainly be lighter than a standard Red 22 2x11 setup but there may also be performance benefits when racing in muddy conditions, too - James Huang/Future Publishing
SRAM builds the CX1 rear derailleur with a 'straight parallogram' geometry similar to what's used on the XX1 mountain bike group - James Huang/Future Publishing
Save for the gutted left-hand lever, the controls appear to be shared with the standard SRAM Red 22 group - James Huang/Future Publishing
Tall teeth with alternating thick and thin profiles on the new SRAM CX1 group should yield the same impressive chain security as with XX1 - James Huang/Future Publishing
While the XX1 rear derailleur incorporates a friction-reducing pulley, the SRAM CX1 rear derailleur instead features a traditional barrel adjuster - James Huang/Future Publishing
The new SRAM CX1 chainring uses a rather deep profile that helps offset the teeth inboard but also should improve bending stiffness, too - James Huang/Future Publishing

SRAM's upcoming CX1 1x11 drivetrain made an appearance in Boulder, Colorado, at the 2014 US National Cyclocross Championship on the bikes of Ryan Trebon (Cannondale-Cyclocrossworld.com) and Elle Anderson (California Giant). SRAM still isn't saying much but the bits look production-ready right now, and they're likely to find a substantial following for next season.

Just as with SRAM's groundbreaking XX1, CX1 is a purpose-built, single-ring drivetrain that uses the company's X-Sync chainring with alternating tooth widths and a clutched rear derailleur pulley cage to ensure chain security without having to run a separate guide. While CX1 should appeal to weight-conscious racers who are strong enough to handle the reduced gearing range, the simplified drivetrain may also offer some performance benefits when racing in muddy conditions.

The rear derailleur design is a close analogue to XX1 but with a shorter cage and a built-in barrel adjuster in place of a friction-reducing pulley. Like XX1, CX1 uses a so-called straight parallelogram geometry instead of a traditional slant parallelogram geometry that SRAM says increases shifting precision on bumpy ground. Chain gap is controlled by an unusually generous offset between the pulley cage pivot and upper pulley.

The new CX1 X-Sync ring mounts to the outer position of what looks to be a standard Red 22 crankset but the teeth are slightly offset toward the centerline of the bike for a more appropriate chainline. We unfortunately weren't able to read the markings on the chain but our guess is that it's the same model as is used on XX1.

Tall teeth with alternating thick and thin profiles on the new sram cx1 group should yield the same impressive chain security as with xx1: tall teeth with alternating thick and thin profiles on the new sram cx1 group should yield the same impressive chain security as with xx1 - James Huang/Future Publishing

Like XX1, CX1's straight parallelogram rear derailleur geometry and hugely offset upper pulley make it a dedicated 1x drivetrain incompatible with multiple chainrings. Riders who are currently on SRAM Red 22 and are interested in making the switch, though, will be glad to hear that they likely won't have to buy much to do the conversion: just a rear derailleur, chain and chainring.

Trebon and Anderson both used standard SRAM PG-1170 cassettes and while their bikes were built with gutted left-hand shift levers, the right-hand levers were standard Red 22 units.

Save for the gutted left-hand lever, the controls appear to be shared with the standard sram red 22 group: save for the gutted left-hand lever, the controls appear to be shared with the standard sram red 22 group - James Huang/Future Publishing

SRAM has pegged the official release of CX1 for later this month so we'll soon have plenty of information to share. Stay tuned.

James Huang

Former tech editor

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