Sram released some more details of its XX1 mountain bike drivetrain, which uses a single chainring combined with an 11-speed 10- to 42-tooth cassette.
The company had released a few photos of the parts in the spring, but gave the press a more detailed look this time. The parts will be available in October. SRAM said it would release pricing information later Monday.
The group includes a dedicated crank with six chainring options, from 28 to 38. The rings can be changed without removing the crankarm. Since there is no front shifting, the tooth profile is optimized for chain retention with alternating profiles to match the chain's inner and outer links (the rear derailleur pulleys have a similar alternating design). The cranks will be available for BBB30 and GXP bottom brackets and weigh about 650 grams with the bottom bracket.
The group's rear derailleur is called the X-Horizon. It has SRAM's roller bearing clutch to reduce chain bounce and sap and a cage lock for wheel removal.
The 11-speed cassette is available in one combination: 10-12-13-16-18-21-24-28-32-36-42, which weighs a claimed 260 grams. It uses SRAM's X-Dome construction and is designed for a new cassette body shape called XD. The company said SRAM and DT Swiss will each have wheels available with the XD bodies.
Finally, the group has trigger shifter or twist shifter options. The twist shifter appears to be a variation of 10-speed GripShift SRAM introduced this spring, with metal indexing steps and three rows of ball bearings instead of the mostly plastic GripShifts of the past