Yeti's planned release of a full carbon version of its pervasive AS-R SL frame wasn't exactly a secret, but the look of the final product was still a very pleasant surprise. The new AS-R C strikes a similar profile to the current model, yet the hugely oversized proportions scream of dramatic improvements in frame rigidity (sorely needed, we might add).

The super wide bottom bracket shell now houses Shimano's press-fit composite bottom bracket bearing cups instead of threads. This also allows the hexagonal down tube to take on equally wide proportions as it approaches the bottom end. The top tube is similarly shaped up front, then switches to a ‘T' shape at the forward shock mount before turning back up towards the… what the? Is that an integrated seat post on a mountain bike? Yup.

Scott was the first to bring the concept to the MTB mass market, but Yeti's system is still rather unique. Users can chop off the top of the frame to fit as intended (the seat post head allows for 25mm of height adjustment), or can saw it off at the base and attach a special clamp that allows for use of a standard 27.2mm post. Last year's 98mm-travel carbon rear end is mostly carried over from last year with the exception of a new random fiber finish, but the old aluminum link is now molded in carbon.

Claimed frame weight is 1.8kg (3.97lb) including a Fox RP23 shock, and suggested retail is US$2499 (frame only, of course). Yeti projects delivery dates beginning in January 2008.

The popular Yeti 575 gets reworked as well and even more thoroughly than the AS-R with an all-new aluminum front end and all-new carbon rear as well. As with the new AS-R C, Yeti ditches its once-trademark top tube knuckle in favor of a kinked hydroformed tube that is lighter and stiffer than previous iterations. The oversized hexagonal top tube flares at the head tube to reinforce the front end (which also includes a newly externally machined head tube), and Yeti's aging plate-style upper shock linkage mount is replaced by a more sophisticated tubular aluminum structure.

The 575 also gets a new rear end with carbon fiber chain stays as well as carbon seat stays that include a unique bridge to keep things tied together. Rear travel remains at 150mm using Yeti's tried-and-true variable leverage ratio linkage design, but weight has dropped to just 2.7kg (5.95lb) including the now-standard titanium hardware kit. Less expensive aluminum rear ends will also be offered which add 200g. Delivery is scheduled to begin in late October.