SRAM will be releasing a new 1×11 system for endurance racers called SRAM XX1.

Built around a single chainring in the front, it gets a new “widest available range” cassette and will incorporate their Type 2 chain management. The rear is 11 speed, they’re noting it’ll work with both trigger and Grip Shift. The system will officially debut at Crankworx Les 2 Alpes on July 9-15.

Details are a scant at the moment, but there are a few things we can tell from the photos. First, that’s definitely a prototype rear derailleur, and the crank arm is two-piece rather than XX’s one piece. If we were betting folk, we’d say the final version might very well be a one-piece crank/spider given that it’s at the XX level. If so, and if it is designed around carrying a single ring, could drop a minimum of 30-40g off the existing set up just at the crankset.

UPDATE: Yep, it’s 11 speeds (better image of cassette added below), which should make it a good fit for the 2013 DT Swiss wheel and hub range, which all move to an 11-speed spacing. (Thanks to everyone that caught that!)

That weight would likely be made up with the addition of the Type 2 clutch mechanism on the rear derailleur, but, if that system negates the need for a front chain guide, the drivetrain ends up being about the same weight…save for maybe a few grams from the monstrously larger big cog on the cassette…

Count ’em: SRAM cranks it up to 11! And as suspected, it mounts up just fine (apparently) to Mavic’s wider freehub body.

UPDATE: If we’re all counting correctly, it’s a 10-42 cassette. No lock ring is visible on the smallest cog, which indicates it is the lock ring. Also looks like the derailleur is bolted onto a direct mount-like “B-Link”. Notice how the cable enters on the inside and appears to come out the outside, making for a potentially interesting pull direction, especially with the parallelograms looking almost parallel to the cogs.

Where the overall system weight savings (and gain in simplicity) comes is with the lack of a front derailleur and shifter. Shedding those components would yield at least a 130-150g savings.

One interesting tid bit we’re trying to get more info on is the thicker teeth on the chainring. Every other tooth is dramatically bulkier. Could be a noise dampening design? We’ve got calls and emails in to SRAM.

The rear derailleur has a very long cage, necessary for the oversized cassette. This prototype has a pretty stout lower parallelogram arm and *gasp* an Avid Rollamajig! We’re just guessing here, but compared to the current 11-36 XX cassette I’ve got on my bike, this one looks like perhaps a 40T big cog…meaning you could potentially have a 1:1 or less ratio!

It’ll be interesting to see if they can put such a massive cog on there and still use the machined out design of the current XX cassettes. More as we get it!

Looks like they’re doing testing on a Cannondale Jekyll, which is a 150mm travel all-mountain (sorry, Over mountain in Cannondale parlance) bike. If the Type 2 clutch system can keep the chain on without a guide for their pro riders, we’re guessing it’ll be pretty stable for the rest of us.