Niner 2021 AIR 9 2-Star Hardtail Mountain Bike (Silver/Baja Blue) (XS)

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Price: $2,099.00 (Save 20%)
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The Air 9 aluminum hardtail blends the agility and efficiency of a pedal-friendly XC bike with the versatility, toughness and capability of a rowdy trail rig. Lightweight and snappy, poppy and peppy, the AIR 9 has plenty of stiffness to get you up to speed when you stomp on the pedals.

Hit the trail big with the 2-Star SRAM SX build, without a big hit to your wallet. Thanks to SRAM's outstanding SX Eagle drivetrain, you can bring every ounce of AIR 9 performance to bear at an affordable price point.  


  • Hydroformed 6061 aluminum frame blends stiffness and comfort in a durable package
  • Race Face bar and stem for outstanding performance and durability
  • SRAM SX Eagle drivetrain provides a wide range of gearing to tackle all obstacles
  • Marzocchi Bomber Z2 Rail suspension fork with 120mm of perfectly tuned suspension 
  • Niner Alloy wheels (Boost Spacing)
  • BioCentric 30 bottom bracket system gives you the freedom to easily go single-speed or geared. 
  • Lifetime Warranty: Ride, race, rally with confidence. Niner has you covered with warranty service, small parts, and a support team that actually answers the phone. Read more here >

Due to availability issues during manufacturing, build specifications are subject to change. Please contact us if you wish to verify build specs before purchase.

Frame: Hydroformed & Welded 6061-T6 Aluminum
Fork: Marzocchi Bomber Z2 Rail (120mm Travel) (15 x 110mm) (44mm Offset)
Headset: Niner Integrated (IS42/28.6 | IS52/40)
Handlebar: Race Face Aeffect R (35mm Clamp) (20mm Rise) (780mm)
Stem: Race Face Aeffect R (35mm Clamp) (40mm Length)
Brake Levers: Sram Level
Brakes: Sram Level
Shifter(s): SRAM SX Eagle (12-Speed)
Front Derailleur: -
Rear Derailleur: SRAM SX Eagle (12-Speed)
Crank: SRAM X1 1K Eagle DUB (32T) (XS/S/M/L: 170mm, XL: 175mm)
Bottom Bracket: SRAM DUB PF30
Cassette: SRAM PG1210 (11-50T)
Chain: SRAM SX Eagle (12-Speed)
Pedals: -
Seat: Niner Custom w/ Chromoly Rails
Seatpost: Niner Alloy (370mm)
Rims: Niner Alloy (30mm Internal Width)
Front Hub: Niner Alloy
Rear Hub: Niner Alloy (XD)
Spokes: Steel J-Bend
Front Tire: Schwalbe Knobby Nic EVO SuperTrail (Addix SpeedGrip) (29" | 2.6")
Rear Tire: Schwalbe Knobby Nic EVO SuperTrail (Addix SpeedGrip) (29" | 2.35")
Color: Silver
Weight: -

*Note: These bikes are fully built by our expert bike builders, then partially disassembled as needed for shipping. Bikes will arrive to you with some basic assembly still required.

This product was added to our catalog on June 28, 2022

Sizing Recommendations for Riders Who Fall Between Sizes:

  • Sizing down will provide a more maneuverable ride while sizing up will provide more stability
Rider Height (Feet)Rider Height (Meters)
XS5' - 5'5"1.53 - 1.65m
S5'3" - 5'9"1.6 - 1.75m
M5'8" - 6'1.73 - 1.83m
L5'11" - 6'3"1.8 - 1.91m
XL6'3" - 6'7"1.91 - 2.01m

Note: All sizing recommendations are provided by the manufacturer and may differ for each rider.


Note: Geometry chart is for 120mm of fork travel
(A) Top Tube Length570mm585mm603mm627mm652mm
(B) Seat Tube Length356mm394mm419mm483mm533mm
(C) Chainstay Length Actual430mm430mm430mm430mm430mm
(D) Horizontal Chainstay427mm427mm427mm427mm427mm
(E) Front Center678mm693mm711mm737mm764mm
(F) Wheelbase1102mm1117mm1136mm1162mm1189mm
(G) Bottom Bracket Drop52mm52mm52mm52mm52mm
(H) Headtube Length100mm100mm110mm125mm145mm
(I) Headtube Angle68.0°68.0°68.0°68.0°68.0°
(J) Seat Tube Angle74.0°74.0°74.0°74.0°74.0°
(K) Stand Over Height698mm729mm748mm800mm841mm
(L) Reach395mm410mm425mm445mm465mm
(M) Stack610610mm620mm634mm652mm
(A) Top Tube Length22.4"23.0"23.7"24.7"25.7"
(B) Seat Tube Length14.0"15.5"16.5"19.0"21.0"
(C) Chainstay Length Actual16.9"16.9"16.9"16.9"16.9"
(D) Horizontal Chainstay16.8"16.8"16.8"16.8"16.8"
(E) Front Center26.7"27.3"28.0"29.0"30.1"
(F) Wheelbase43.4"44.0"44.7"45.8"46.8"
(G) Bottom Bracket Drop2.05"2.05"2.05"2.05"2.05"
(H) Headtube Length3.9"3.9"4.3"4.9"5.7"
(I) Headtube Angle68.0°68.0°68.0°68.0°68.0°
(J) Seat Tube Angle74.0°74.0°74.0°74.0°74.0°
(K) Stand Over Height27.5"28.7"29.5"31.5"33.1"
(L) Reach115.5"16.1"16.7"17.5"18.3"
(M) Stack24.0"24.0"24.4"24.9"25.7"