Frameset
Frame
Niner Hydroformed and Welded 6061-T6 Aluminum
Fork
FOX 34 SC FLOAT FACTORY EVOL FIT4, 3-position w/ adj, Kashima coat, 120mm, 110x15mm, 44mm offset
AIR 9 2-Star SRAM SX Eagle
The current-generation Niner AIR 9 is a clear departure from earlier, more race-oriented AIR 9 hardtails. Introduced for 2018, this version shifted decisively toward what Niner called “trail-country”: still light and efficient in concept, but designed around more capable trail manners. The frame uses hydroformed 6061 aluminum, Boost 148 rear spacing, and clearance for either 29x2.4-inch tires or 27.5x3.0-inch rubber, which gives it a broader operating range than a pure XC hardtail. It is also built around a 120mm fork rather than a shorter, traditional cross-country setup, reinforcing that this bike is meant to do more than just cover smooth singletrack quickly.
What makes the AIR 9 distinctive is that blend of hardtail simplicity with modern trail-bike priorities. The geometry refresh brought a longer front center, shorter 430mm chainstays, a slacker 68-degree head angle, and a steeper 74-degree seat angle, all aimed at making the bike more stable and more centered on technical terrain without abandoning pedaling efficiency. At the same time, Niner preserved unusual versatility for this category: the frame supports geared or singlespeed use via the BioCentric system, includes internal dropper routing, and accommodates both 29er and 27.5+ configurations. In the market, that places the AIR 9 less as a pure XC race hardtail and more as a modern aluminum trail hardtail for riders who want efficient climbing, straightforward maintenance, and broad setup flexibility.
$1,500
Image pending
Build
Size
| Stack | 620mm |
| Reach | 425mm |
| Top tube | 603mm |
| Headtube length | 110mm |
| Standover height | 748mm |
| Seat tube length | 419mm |
Fit and geometry
The AIR 9’s geometry is notably progressive for an aluminum hardtail with cross-country roots. Across the size range, the 68-degree head tube angle is considerably slacker than older XC norms, which should give the bike more confidence on descents and better composure when the trail gets steeper or rougher. The 74-degree seat tube angle keeps rider weight reasonably centered for seated climbing, while the short 430mm chainstays help the bike stay responsive and easier to manual or unweight over trail features. A consistent 52mm bottom bracket drop also suggests a fairly planted ride feel without going excessively low.
The sizing numbers support that trail-oriented intent. Reach grows from 395mm in XS to 465mm in XL, with a 425mm reach in Medium and 445mm in Large, giving the bike a roomier cockpit than older hardtails of this type. Wheelbase figures of 1136mm in Medium and 1162mm in Large point to stable handling, but not to the point of feeling overly stretched or cumbersome. Stack is also fairly generous—620mm in Medium and 634mm in Large—which should make it easier to achieve a comfortable, slightly more upright trail position rather than an aggressive race stance. Overall, the geometry points to a hardtail that favors balanced fit, descending confidence, and all-around trail usability over razor-sharp XC handling.
Full specs
Groupset
Shift levers
SRAM SX Eagle, 12-speed
Rear derailleur
SRAM SX Eagle, 12-speed
Cassette
SRAM PG-1210, 12-speed, 11-50T
Chain
SRAM NX Eagle, 12-speed
Crankset
SRAM X1 1K Eagle DUB, 32T (XS/S/M/L: 170mm, XL: 175mm)
Bottom bracket
SRAM DUB PF30
Front brake
SRAM Level hydraulic disc
Rear brake
SRAM Level hydraulic disc
Front rotor
180mm SRAM G2CS
Rear rotor
160mm SRAM G2CS
Wheelset
Front wheel
Niner Alloy wheel, aluminum clincher, 30mm internal width, 110x15mm, 6-bolt
Rear wheel
Niner Alloy wheel, aluminum clincher, 30mm internal width, 148x12mm, 6-bolt
Front tire
Schwalbe Nobby Nic EVO Super Trail TLE, Addix Speedgrip, 2.6
Rear tire
Schwalbe Nobby Nic EVO Super Trail TLE, Addix Speedgrip, 2.35
Cockpit
Stem
Race Face Aeffect R, 40mm, 35mm clamp
Handlebars
Race Face Aeffect R, 780mm width, 20mm rise, 35mm clamp
Saddle
Niner Custom w/ Cr-Mo rails, embossed Niner graphic
Seatpost
KS LEV Si dropper (XS/S: 100mm, M/L/XL: 150mm)
Grips
Niner Grrrips L/O Nylon Soft Compound
Builds
The available build information here is limited, but the listed complete bike is the 2-Star SRAM SX Eagle at $1,499.99. At that price, the AIR 9 sits in the affordable end of the modern trail-hardtail market, with the main selling point being the frame platform itself: hydroformed aluminum, Boost spacing, 120mm-fork design, and the ability to run either 29-inch or 27.5+ wheels.
Without a fuller build sheet, there is not much basis for detailed component comparison, but the SX Eagle designation indicates a SRAM 1x12 drivetrain at the entry-level end of Eagle. That makes the bike’s value proposition relatively straightforward: riders are buying into Niner’s versatile, updated hardtail chassis at a modest price point, with a parts kit aimed more at accessibility than premium performance.
2-Star SRAM SX Eagle
$1,500
Selected