Mountain Gear

Singletrack Tech Gallery: Niner Air 9 Carbon

Geared or SS versatility can be yours on big wheels in early 2010 with Niner's Air 9 Carbon.

Amongst other cool features, the Niner Air 9 Carbon is designed to run either geared or singlespeed. CHECK OUT MORE PHOTOS BELOW Photo by Michael Darter
Amongst other cool features, the Niner Air 9 Carbon is designed to run either geared or singlespeed. CHECK OUT MORE PHOTOS BELOW Photo by Michael Darter

We first got a look at Niner’s new Air 9 Carbon hardtail at Interbike in September. It turned our heads as it marked Niner’s first effort in carbon fiber.

At first glance, they had done a sweet job in working the black magic with fiber and resin, sculpting a light, sexy frame for the 29er wagon wheel set. Now we have time to take a closer look.

The tech editors at our sister publication, VeloNews, are putting the final touches on the Buyer’s Guide (available in January) and they gave us the heads up on Niner’s new frame. As awesome as the Buyer’s Guide is, there’s never enough room to give every rig the treatment it deserves. The feature-filled Air 9 Carbon is one of those bikes with a longer story to tell.

We didn’t have time to ride this bike, but wanted to spread the word about its versatility. Hopefully we’ll have one in-house for testing before too long (Niner says the Air 9 Carbon is available in March). From what we’ve seen, it’s a one-of-a-kind rig.

Crafted from Carbon

Niner Air 9 Carbon
Frame: $1,899
Anticipated delivery: March 2010
Carbon frame that can be run as SS or geared
Internal cable routing
Available in Tang or Vana White

The Niner crew did their homework before building the new Air 9 Carbon. After years of building 29ers in aluminum and scandium, broaching the carbon fiber construction barrier required some research. They tell us they started with extensive analysis of testing data to help determine primary tube shapes. No longer confined to round, cut or swaged metal, the new opportunities in tube and frame shapes were almost limitless. Engineers used finite element analysis, physical mock-ups and gradually refined the industrial design process to meet every weight, strength and stiffness target.

As a result, the downtube and BB area is massively oversized, with a hexagonal down tube for lateral stiffness. Almost the entire frame is molded carbon fiber with inclusions of high modulus fibers in key layers and layup patterns. Aluminum inserts in critical interfaces (headset, bottom bracket, brake posts) allow tight tolerances to be met and add durability where needed.

Fine — Have It Your Way!

Carbon fiber construction aside, possibly the coolest thing about the new Niner is the degree of versatility built in. The bottom bracket shell is Niner’s new “CYA” system, which is compatible with almost every bottom bracket standard in the industry, plus Niner’s proprietary Bio-Centric EBB. The way CYA works is that the frame is essentially a blank slate, with a giant, hollow, threadless bottom bracket shell. Your choice of BB inserts is available to run a standard threaded BB, the new BB30 bearings, or Niner’s own eccentric threaded BB shell, called the Bio-Centric EBB.

The Bio-Centric EBB works just like most eccentric bottom brackets in that it permits the whole crank and BB to rotate forward or back to tension the chain. But unlike most eccentric BBs, it’s a two-piece design with close tolerances such that the bottom bracket will line up the two EBB cups perfectly. Also unique to the Bio-Centric EBB from Niner are the flanges, which go all the way around the EBB shell, and are designed to clamp against the sidewall of the shell as an offset fixing bolt is tightened. Essentially, in the blank slate of an EBB shell, the two halves of the Bio-Centric BB fit into place, are lined up by the bottom bracket, and secured with a fixing bolt. Niner says the design eliminates creaking and, most importantly, allows the Air 9 Carbon to be run as a singlespeed. With just a 6mm Allen wrench, the EBB can be adjusted on the fly or in the field, and Niner says it’s the lightest EBB system on the market.

The final piece to the versatility angle on the Air 9 Carbon is interchangeable rear dropouts, which can be fitted to accommodate either a single cog or a derailleur. The vertical dropouts don’t allow fore/aft wheel adjustment for chain tension (the EBB takes care of that). But if you prefer to run a geared setup, there’s a dropout with a derailleur hanger to meet your needs.

At the end of the day, it could be one of the more versatile carbon hardtails we’ve seen. Choose your fork (rigid or suspended), gearing (single or geared), the rest of your parts pick and hit the trails.

The only thing Niner’s Air 9 Carbon can’t do is accommodate 26-inch wheels. That’s why it’s called a Niner: they only make 29er bikes, because they believe big wheels are your ticket to salvation.

We can’t promise eternal life, but we’d love to ride this rig…

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