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!
6 Comments
Sep 21, 2012
Sep 20, 2012
I don't think it's something I'll get anytime soon, but I'm sure there's a decent market out there.
Sep 19, 2012
Sep 19, 2012
I am curious how they can synch that chain on the cogs with each shift?
They don't mention chain-line angle, one big reason I don't go 1x8.
Finally the range of ratios is a big step back. For a 12-32 cassette and 22-44 rings the range of ratios is 5.33, compared to a sad 4.20 on this setup.
I love the invention, though! Keep on!
Sep 19, 2012
One other big advantage of this group is the simple fact that there is no front derailleur - it frees up space in a crowded area of the bike, giving more freedom to frame designers/engineers for tucking the rear wheel in tight, or fitting suspension linkages, etc.
Sep 19, 2012
The rings have alternating teeth thickness, which are designed to work with the new chain (which is probably narrower than a 9 or even 10spd chain). Narrow teeth fit between the inner plates on the chain, thicker teeth fit between the outer plates. It just gives the chain less room to wiggle on the ring, and combined with the clutch type rear derailleur, it basically eliminates the chance of dropping a chain. The chainrings are only available in even numberd teeth because of the alternating tooth thickness.
I hope it trickles down to X0 and X9 levels so regular people can afford it!