The original Niner AIR9 RDO was the second generation of their carbon hardtail AIR9, which was known for its spine rattling stiffness. The RDO, then, was made not just lighter, but also more compliant with the goal of making it more comfortable than the original.

But, Niner says that reworking of the layup also resulted in less lateral stiffness than a top-level race hardtail should have. While it was no slouch in our own testing, the chance to rework it also opened up opportunities to make it lighter and modernize the geometry. Borrowing the long, slack “XC” geo from the recently introduced RKT9, the all-new 2017 Niner AIR9 RDO gets some big changes and an impressive 10% weight reduction…

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

To retain the improved comfort of the first RDO and improve performance, they essentially split the frame into top and bottom halves. The top adds compliance with thinner top tube and seatstays, and the seatpost drops down to a 27.2 diameter.


They slackened the headtube a full degree to 70° with a 100mm fork and stretched the front center slightly. The revised geometry also allowed for improved fit by making the headtube up to 20mm shorter on smaller sizes. That means their racers no longer need to slam the stem or remove dust caps to get low enough, and all sizes put the rider in a more aggressive position.

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

Down low, the frame is optimized for stiffness and snappy acceleration by way of an broad downtube and full width bottom bracket shell, which leads into…

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

…Boost 148 rear axle spacing. The extra axle width let them chop 4mm off the chainstay and bring them down to 435mm while also bumping chainring capacity up to a huge 38t on a 1x setup (up from 32t).

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

It also made room for a health 2.4″ of rubber with space to spare. They could have made the chainstays shorter but said 435mm was the right length for stable handling and proper rider weighting while climbing.

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

Frame weight came down a whopping 10% on average. Old frames averaged about 1,180g, these are hitting about 1,050g with hardware, seat collar and derailleur hanger, plus paint and protective tape. The only thing that weight doesn’t include is the rear Maxle. Titanium frame guards and rubberized chainstay protector come standard.

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

They say much of the weight savings comes from the refined top section and by going to a larger box section BB, which allowed thinner walls. But, inside is a continuous carbon tube through the BB shell, which means compatibility with their Biocentric 30 EBB. As such, this bike replaces both the AIR9 RDO and the One9 RDO and now works with all modern drivetrains. You could even throw a triple on there if you want.

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

Other than water bottle bosses, the only metal on the frame is found in the brake mounts. All frame sizes fit two water bottles. Not shown, there’s a new cable/hose routing port under the BB that eases installation…which was necessary because of the new solid BB tube. While 27.2 dropper posts are rare, the frame is stealth dropper compatible…and Di2 and Sideswing compatible, too.


Geometry numbers are based on a 100mm suspension fork (click to enlarge), but they say it’s fine with a 120mm fork, too.

2017 Niner AIR9 RDO lightweight carbon fiber hardtail race mountain bike

It’ll be offered in CMYK and black/red color schemes. The matching wheel graphics are show only, but they may do them if demand is there. We think they should. Six complete bike builds will be offered:




  1. Isn’t the RS1 heavier than a SID? I think the reason Rock Shox came up with the RS1 is so it could nicely complement the forms of high-end carbon frames. Also, because the upper tubes and not the lower ones get painted on RS1s means they can be customized to match the frame’s paint scheme. So yeah, the RS1 is about flash, and this bike would be lighter with a different fork that performs better. Down with the RS1.

  2. I don’t see the switch to a 27.2mm seatpost standard as an improvement. 31.6 or 30.9 allowed for more choice of the dropper seatposts and you could still use shims if you wanted to add compliance with a 27.2 seatpost. If there is only one area where shims works great it is in the frame/seatpost interface.

  3. I carried Niner in our shop at one time. Met the founder/owner Chris at Interbike during a time when we were doing a significant amount of business with Niner and I did not get a “thanks” or “great to stop by” or “hope you had a good season”. He did not care that I was a dealer and that our shop worked our A$$es off to sell HIS brand. He is the Lee Iaccoca of the bike industry – on one hand a great business person, on the other, a complete jerk to work for or with or as a dealer. The jerk side of things can be so bad it hurts the good business side of things. Overall, they are not into building relationships with dealers – they want you to fit exactly within their aggressive business model to take over the bike industry and for you, the dealer, to take all the risk all the while, as a multi-faceted bike industry professional, you know that 27.5″ is better for enduro riding so you are therefore not going to put all your eggs into one basket. The operations people (ex. Shimano/Pearl Izumi people) are Trek wantabees who threaten to cancel your account if you decide not to take stock with bad deadlines, margin, and horrible net 30 terms (these deadlines and terms changed annually). The people who are selling Niner do it because they love the brand – not because it’s the best business decision. Overall, I like(d) the product but when you work “internally” in the industry you see through the marketing hype and sometimes seeing these ads makes me want to puke. Sorry to all the Niner lovers but that’s my cold hard truth.

  4. I demo’d an Air 9 Carbon RDO in Fruita Colorado 4 years ago and could not believe how stiff the bike was. It was worse than riding an old straight gauge tubed Cannondale hard tail. I shook me to the core. When I brought the bike to the Niner booth they asked how I liked it and I shook my head and said, “why the fuck is it so stiff”. The Niner guys laughed and said, “yeah, we get that a lot”. Then they said, “the RDO you rode is least stiff of the bunch, the standard Air 9 Carbon is more stiff”? Holy shitt. No thanks. Never looked at these frames again. I love how they made this new frame stiffer. WTF?

    • 4 years ago? That would have been the original version which I had too. It was stiff, yes, but pure power to the ground. Loved that bike. I guess that’s why it is important to demo.

      I’ve called their service a few times and talked with Ralph about a few setup issues and ordering some items which were not on their website. He picks up the phone and really takes the time, unlike other companies I’ve dealt with like they have bigger fish to fry. I’ve never dealt with mgmt like frustrations from Fred as noted above, but Ralph is always super helpful!

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