This year SRAM is introducing a new 11spd drivetrain that targets both XC and gravity riders alike, which seems like a crazy idea. But it turns out the company has done their homework once again and have put together a well thought out system called XX1.
Im a solidly XC-rider myself and Ive been riding 1×9 for 3 years now; I love the simplicity and for most trails I have all the gears I need. But still, there are disadvantages to running a 1-by drivetrain: chain slap (short cage derailleurs help), chain drops (most riders use some type of chain retention device), and a limited range of gears (naturally). SRAM understands these issues and designed the XX1 accordingly.
The XX1 rear derailleur features SRAMs Roller Bearing Clutch technology to reduce bounce and chain slap. Essentially, SRAM has added a brake that keeps the derailleur from being jostled forward by normal bumps on the trail. In fact, despite riding gullies and washboard trails at Outdoor Demo I never got the chain to slap (the white test bike I rode verified this with zero grease or chipped paint on the chainstay). Theres no need to run a chain retention device or even a chainstay protector, which results in a big weight savings by itself.
SRAM is offering an XX1 cassette geared 10-42 which is a HUGE range of gears. The 42-tooth ring offers a big jump over the next closest 36-tooth ringessentially a granny gear for 1-by riders. SRAM also created a new driver body for the XX1 called the XD. The XD does away with the lock ring on a traditional cassette (they needed the room!), which also saves weight at the same time.
Teeth on the XX1 cassette and 28-38 chain rings feature an alternating profile thickness meaning existing chains wont be compatible. Why? SRAM claims the alternating thickness provides maximum chain control. Now I dont understand the engineering behind this but it does seem like it could cause some issues when fixing a chain on the trail after a break. Also, like the 10spd chains, the XX1 chain features a Powerlock (tool required to remove, non-reusable) instead of a Powerlink. One upshot is SRAM claims the new chain offers an improved life span.
Traditional trigger shifters and grip shifters are available for the XX1 and for now there is no X0-level option. The XX1 crank arms are made from carbon fiber (natch).
I rode a Kona Satori tricked out with XX1 and I have to say the new drivetrain delivered as advertised. The whole system is super lightweight, versatile, and low maintenance. But as usual, that comes at a priceexpect to see the XX1 popping up on only high-end bikes initially.
The XX1 certainly scratches me where I itchI cant wait to see this take off!