The ASR-7 and SB-66 weigh the same, and can easily break the 30lb barrier with similar component packages. They also share the same bottom bracket height -- but the similarities stop there. The ASR-7 is a seven-inch travel bike, equipped with a full inch more travel than the SB-66. But, the defining differences between the SB-66 and ASR-7 are the suspension system and geometry.
The SB-66 has a unique eccentric pivot design that provides an axle path with a rearward motion, where the ASR-7 opts for Yeti's proven Active Suspension -- a simpler 'single pivot' design that has an arcing axle path. Don't let the single pivot designation place this bike in the same category of flexy single-pivot bicycles, though. Yeti's AS design relies on a 'dog bone' link, that's constructed of high modulus carbon, to prevent side loading of the Fox RP23 rear shock.
This, along with the heavy-duty bearings, offers ultra-smooth action, and ideal pivot locations give the ASR-7 distinct, ride-enhancing characteristics. The stout dog bone ties together a hydroformed main triangle and rear swingarm for a stiff, line-holding chassis. An added benefit of the AS design compared to multilink systems is a lack of complicated, flex-permitting, and chainstay-lengthening links. Because of this, the ASR-7 is not only incredibly stiff, it has relatively short 43cm chainstays.
The chainstays are about 5mm shorter than the SB-66, and keep in mind that the ASR-7 has a full inch more travel than the SB-66, too. Now consider the arcing axle path of an ASR-7; it further shortens the chainstay length when compressed vs. the lengthening of chainstays with the SB-66. Shorter chainstays combined with more travel give the ASR-7 a noticeably livelier nature when negotiating technical downhill terrain. The SB-66 may pedal better over sharp bumps and be less fatiguing on 40-mile backcountry adventures, but when the trail favors tough descents we're throwing a leg over the ASR-7.
Another reason to opt for the ASR-7 when the terrain has long, technical descents with punchy climbs is its slack, 66.8 degree seat-tube angle and shorter effective top-tube length. This allows for a compact cockpit when the seat's dropped to offer increased maneuverability, or conversely, it will stretch out the cockpit when raised for an efficient-when-pedaling cockpit. In comparison the SB-66 has a 70.9 degree seat angle and a longer effective top-tube that will not offer the same cockpit variation from pedal-able to toss-able as the ASR-7.
One misleading stat between these two bikes is their head angles. Surprisingly, the marathon-ready SB-66 has a slacker headangle than the gnar-hound ASR-7 -- 67 vs. 65.9 degrees. Again, you need to consider the arcing axle path when looking at these numbers. The eccentric pivot on an SB-66 will help maintain its head angle throughout its travel, providing a consistent 65.9 degrees. The ASR-7 is going to slacken its angle as it runs through its travel. In fact, when the ASR-7's shock is sagged, it'll sport a head angle right around 68 degrees.
To summarize, if you're aiming for gravity-assisted, technical downhill runs peppered with jump lines and stunts that require occasional pedaling, the ASR-7 is your ride. If you plan on skipping the shuttle to ride up, down, and all-around, you're going to want an SB-66 under you -- though we're not saying the ASR-7 can't do that too. Just that the ASR-7 would be our favorite on trails where a dedicated downhill bike is overkill and the SB-66 could be overwhelmed.
The Yeti AS-R 7 Frame with RP23 comes in Small, Medium, large, and X-Large.