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The AIR 9 is a highly respected tool of the hardtail trade, and it's difficult to believe that Chris Sugai and his band of overachieving engineers could improve on that platform. But, not surprisingly, it happened. In fact, Niner actually developed a completely new chassis, worthy of Niner's RDO designation -- an acronym for 'Race Day Optimized.' Now, the AIR 9 RDO has been transformed into an entirely different animal that's clearly aimed to place you on the podium.

While this frame shares the AIR 9 name with Niner's versatile carbon hardtail, that's about all that they share. Niner eliminated all excess on this frame, and instead, focused solely on making it as light as possible. For example, the rear brake mounts are now cleanly located inside the stays in order to reduce the amount of hydraulic line needed. Not only does this shave gimme' grams, but it makes the AIR 9 RDO look lean and mean, as well. Also, this frame doesn't use Niner's CYA bottom bracket system. And while the CYA is renowned for its versatility, it would've added complexity and heft to this purpose built race machine. So, Niner went with the lighter PressFit 30 interface instead. However, the RDO does retain the clean internal cable routing and titanium chain-slap protectors that're found on the AIR 9 Carbon.

The AIR 9 RDO isn't just cosmetically and physically different from the AIR 9 Carbon, it's structurally different, too. At the core of every Niner frame is extensive computer-based finite element analysis, and here, it was used to develop a high modulus carbon fiber structure with optimized weaves, lay ups, and tube shapes that produced the lightest Niner to date. We should also add that the RDO's fluid form is no accident. In fact, it was designed in order to dampen chatter and guide impact forces to the stronger parts of the frame. Now, chain torque goes directly to the rear wheel via the large bottom bracket shell and shapely chainstays. Meanwhile, trail vibrations are thoroughly quelled by the swooping seatstays. Niner ties the bottom bracket to the strength- and precision-enhancing tapered head tube via a large down tube in order to ensure that the frame tracks true and responds to every input.

The RDO uses a 31.6mm seatpost and a high-mount, bottom-swing, and bottom-pull front derailleur with a 34.9mm clamp. The rear triangle provides clearance for tires up to 2.4in, and staying true to its XC nature, the AIR 9 RDO only uses 160mm rotors, with the caliper attaching via a post mount. Niner recommends a maximum chainring size of 26/39t for SRAM or 28/40t for Shimano for two-by applications in order to avoid interference issues. Any traditional triple setup will also work fine.

Niner recommends 80 to 100mm suspension forks, or for the lightest setup possible, a rigid unit with a 470mm axle to crown length and 45mm offset. Perhaps, not coincidentally, Niner's award-winning carbon fork shares those exact dimensions. The tapered head tube comes equipped with a Cane Creek IS42/28.6 | IS52/40 integrated (Campy style) headset. For those of you who intend on running a one-by drivetrain, such as SRAM's XX1, the AIR 9 RDO will clear up to a 32t ring, with a 168mm Q Factor crankset.

The Niner AIR 9 RDO Carbon Mountain Bike Frame - 2012 is available in four sizes from Small to X-Large and in the color Licorice.

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What do you think about this product?

Have questions about this product?

LOVE this frame.

  • Familiarity:I've put it through the wringer

I paid $2,000 for my XL frame a couple of years ago, and it is still going strong. It is a quality carbon frame. With a top of the line XX1 build and Easton EC90 wheels it weighs 20 lbs even. In the fall, this frame does double duty as a cross bike, I throw on a rigid Niner carbon fork and lightweight tires and it weighs only 17.5 lbs, which is actually lighter than my carbon/Ultegra road bike.

I suspect that there are a couple of reasons why this frame is on mega clearance: first, the big XL size doesn't fit many people. It fits me great, I'm 6'3" and 180 pounds. The second reason is that I suspect that very soon Niner will be updating this frame to the 142mm rear axle standard. This may not bring any weight savings, but will be an update to fit in with this trend of the marginally stiffer 142mm thru-axle. I will be riding this frame for a few more years before seeing any need to upgrade, it is holding up great.

Hello - will this bike take an xo1 set up...

Hello - will this bike take an xo1 set up 10x42?


That is a great question. You should have no problems running xo1 set up with 10x42 cassette, but a 34t chain ring and bigger will give you compatibility problems. If you have any additional questions, please feel free to email me at

I have the XX1 156q crank, will this not...

I have the XX1 156q crank, will this not clear? Also, 32t as the largest gear in a 1x, no clearence to go to a 34 or 36? This might be a deal breaker for me. Love the frame and price though!

Unfortunately, an XX1 156q factor cranks with a 32t chain ring will give you problems on that frame. Even though the Niner Air 9 is one of our favorite bike frames, it can have some compatibility restrictions. Feel free to contact me to discuss any other frame options that may be a better fit for your needs and I will do my best to help.

I just bought this frame, and while building...

I just bought this frame, and while building it the rear chain stay protector fell off in my hand (!!) How do you re attach? The sticky tape isn't sticky enough to re adhere to the frame

Would really like to buy this frame... but...

Would really like to buy this frame... but does it have a meduim? My query also goes to Air 9 carbon. And are you shipping items to Courtenay BC. Please respond, many thanks!

Best Answer

At the time of this posting, it seems that the only size frame that BC is stocking currently is a size XXL. Also, there are certain brands that BC cannot ship outside of the US; unfortunately, Niner would be one of those brands. For a complete list, I've included a link to the brands that Backcountry can and cannot ship if you want to view it for yourself in case you have anymore questions about a particular item, and whether or not it can be shipped to Courtenay, British Columbia. ( Best of luck, sorry to be the bearer of bad news.