<b>The XX1 Drivetrain - a simpler and lighter 1x11 solution from SRAM that will be available this October.</b>
The unique “horizontal parallelogram” design and pulley offset on the new X-HORIZON rear derailleur keeps the chain gap constant across all 11 gears (you'll see it in action on the next slide). This is said to provide fast, precise shifts, reduce shift force and eliminate ghost shifting. The derailleur is also equipped with SRAM's TYPE 2 technology, which reduces bounce and chain slap. 220 grams.
Standard cassette on the left, the new XX1 cassette on the right. The XX1 has a 10 to 42-tooth range and 11-speeds. That's huge when compared to the standard 11-36 option. The larger range makes a 1X drivetrain more feasible for the average rider. You'll still have an easy gear for climbing and a hard gear for mashing on the downhills.
The single-unit cassette combines with a unique "XD" driver body on the rear hub. SRAM says this creates a better connection to the wheel, and also allows for the 10 tooth cog which has a smaller internal diameter than traditional cassettes. Wheels equipped for the XD driver body will be available from SRAM and DT Swiss.
The cassette is machined from a single piece of billet steel, and has an “open” interior known as X-DOME. SRAM says this gives riders better mud clearance, less weight, cleaner shifting performance and longer component life. 260 grams.
The XX1 crank is mated with a very unique "X-SYNC" chainring. Note the alternating thicknesses on the teeth. Developed for maximum chain control, each tooth’s thickness is precisely CNC-machined to support the chain’s inner and outer links.
Each chain ring fits a single, universal spider - allowing you to change rings without removing the carbon XX1 crank arm. Weight is 650 grams with the BB30 bottom bracket.
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.
The new 1X11 XX1 specific chain is designed to deliver the greatest strength and reliability to a drivetrain that doesn’t have to make compromises for front shifts.
Several versions of the new XX1 rear derailleur were made before the final product was ready. Prototype, test, repeat... Once the mechanical function was dialed, SRAM took a step back and studied the aesthetics of today's bikes before arriving at a final design.
As a complete package, the XX1 drivetrain certainly looks the part. The numbers are good and the simplicity of the system is very appealing. Our only real concern is chain retention. Does the X-SYNC chain ring really solve it? We'll be riding it in the near future and will report back on how it performs.