Niner ONE 9 RDO Carbon Mountain Bike Frame $2,149.00
One speed: FAST.
Riding a singlespeed takes grit. It may not be for everyone, but for those who get it, the satisfaction of crushing hills at a relentless pace is hard to beat. Since there’s a devoted following of singlespeed XC racers, Niner adapted its AIR 9 RDO to a simpler setup, and the result is the ONE 9 RDO Carbon Mountain Bike Frame. As its lineage would indicate, it’s light, stiff, and blazingly fast. And that translates into super-fast lap times, along with the perverse satisfaction known only to those who prefer to do things the hard way.
The ONE 9 RDO benefits from all of the weight saving measures that have made the AIR 9 RDO the notorious race-rocket that it is. At the core of every Niner frame is extensive computer-based finite element analysis, and here it’s used to develop a high modulus carbon fiber structure with optimized weaves, layups, and tube shapes — ultimately producing the lightest Niner to date. The RDO’s fluid form is no accident, and it's designed to minimize chatter and guide impact forces to the strongest parts of the frame. Chain torque goes directly to the rear wheel via the oversized CYA bottom bracket shell and shapely chainstays, yet trail vibrations are quelled by the swooping seatstays. Niner ties the bottom bracket to the precision-enhancing tapered head tube via a large down tube to ensure the frame tracks true and responds to every input.
What separates the ONE 9 RDO from its AIR 9 ancestor is the use of Niner’s CYA bottom bracket interface. It’s oversized to make room for the included BioCentric eccentric bottom bracket. Unlike other EBBs, BioCentric has a track record of being easy to use and remaining creak-free, but the real benefit is that it allows for the use of a fixed rear dropout. On top of being the lightest option, it avoids the slippage that can occur with some sliding dropouts, and it’s worlds easier to use in the heat of a race than horizontal dropouts. And should you change your mind at some point and want to run gears, you can swap the bottom bracket to Niner’s fixed-position CYA insert, add a derailleur hanger, and run any of the one-by drivetrains on the market.
Niner recommends an 80 to 100mm suspension fork, or a rigid unit with a 470mm axle to crown length and 45mm offset. Perhaps not coincidentally, their 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. You’ll need a 31.6mm seatpost and a 35mm seat clamp. The rear triangle offers clearance for tires up to 2.35in. It accepts only 160mm brake rotors, a limitation that’s befitting its cross country focus. The caliper attaches via a post mount. The maximum chainring size varies depending on the position of the BioCentric EBB insert, which accepts a standard 73mm BSA bottom bracket. At the most rearward position, the Niner recommends running no larger than a 28t chainring, and when in the forward position, it will accept a 36t ring.
The Niner ONE 9 RDO Carbon Mountain Bike is available in four sizes from Small to X-Large and in the color Atomic Blue.