Niner ROS 9 – Steel, Long Travel Hardtail Released

29er Enduro

From the Manufacturer

The hardtail for riders that don’t like hardtails. No twitchy high-posting around features you would hit on your “real” bike. No need to back off because your XC racing head angle prevents solid roosting. The ROS 9 won’t judge your lines – it lets you write checks your skills might not be able to cash, and what is more exhilarating than that? Short chainstays, slack head angle, and oversized headtube nourish these Roots of Steel – all with the ability to tweak the geometry via the BioCentric II. Run this rig singlespeed, 1x or fully geared with a front derailleur if you roll that way. Remove the cable guides and front derailleur mount if you don’t. Stealth routing for the dropper post keeps the ROS 9 fresh and clean. Sorry, the ROS 9 is not compatible with heart rate monitors or training plans but it will certainly earn you some PRs when you do your part keeping the rubber side down. Ride Over S*!t – The new ROS 9 injects hardtails with a huge-ass dose of fun.

  • Rowdy steel radnesss from the 29er-only mountain bike company
  • Zero mm of suspension is efficient in every chainring
  • 44mm OS headtube is compatible with 120-140mm forks
  • Geometry is slack and low with extra-short chainstays
  • Biocentric II enables perfect singlespeed setup and allows geometry fine-tuning
  • Forged frame details and internal or external dropper post routing
  • 142mm x 12mm rear spacing
What Makes the ROS 9 Tick?

The 4130 Cro-Mo tube set of the ROS 9 is the trusted standard for durability and ride quality. Following the lines and design language of the SIR 9, these tubes have been beefed up to handle the abuse the ROS 9 is designed to shrug off. The super-short chainstays provide a lofty front end feel while the slack headtube angle keeps the front end composed at Mach Loony speeds. A neutral BB height can be made low or high to slay YOUR trails by positioning the BioCentric II where it will do the most good.

Construction details abound – We borrowed the unique dropout design we developed for the SIR 9 to allow 142x12mm Maxle use and house the stout alloy derailleur hanger. The dropout designs allow the chain stays and seat stays to be welded at any angle and provide far more surface area for a full weld around the tube’s end. The front derailleur hanger is removable with an alloy cover. Internal dropper post routing is optional, another alloy cover closes the port if you choose not to use it. Externally routed dropper posts utilize mounts under the top tube. Tabs under the bottom bracket shell accept an proprietary MRP XCG bash guard for optional extra protection. Full-housing cable routing for front and rear derailleurs using Niner’s bolt-on double housing clamps along top and down tubes complete the versatility. If you don’t need the guides, take them off and enjoy the clean look of the frame in singlespeed mode.

Oversized Headtube

The oversized headtube of the ROS 9 allows the use of tapered fork steerer tubes that measurably reduce fork deflection, which means your Niner tracks straight and true. The full spectrum of riders from xc racers to all mountain shredders benefit from these features which is why we incorporate the technology in all our new frames. The ROS 9 Lets you take full advantage of increased steering precision as you get yourself into trouble.

Bio-Centric II Bottom Bracket System

The Niner BioCentric II makes adjustments easy across a wide range of gears and eliminates the need for adjustable dropouts, giving the cleanest possible solution for singlespeed use. No bolt on hubs, no chain tensioners cluttering your ride, no brake adjust¬ments with gear changes. Additionally, BB positioning allows fine-tuning of geometry. Want shorter chainstays? A lower BB? Steeper or slacker seat angle? It’s all achievable with the BioCentric II.

Greater Range – The BioCentric II offsets the bottom bracket spindle 8.5mm from center, offering greater range of adjustment compared to a traditional EBB setup. More offset is a boon when changing gears without having to change chain length and it al¬lows riders to make more noticeable changes to frame geometry.

Reliable Function – Traditional EBB units are held in place with set screws that can become difficult to finely adjust over time, or ex¬pansion wedges that can deform the bottom bracket shell of the frame. Split bottom bracket shells that clamp an EBB can stretch or ovalize. The Bio-Centric II avoids these troubles by using two bolts to apply a clamping force on the outside edges of the BB shell, eliminating the possibility of ovalizing or indexing the shell.

ROS 9 Specifications & Compatibility
  • 73mm BB width (with BioCentric II installed)
  • BioCentric II is compatible with external bearing cranksets only
  • Direct mount front derailleur, high mount, top pull, removable front derailleur mount
  • Tabs under BB shell for custom MRP XCG Bash Guard – available separately at
  • 31.6mm seat post size, compatible with internal and external dropper post routing
  • 34.9mm seat collar size
  • 44mm headtube. Tapered headset with internal (ZS) top cup and 1.5” external bottom cup (included with frame). Cane Creek standard description: ZS44/28.6|EC44/40
  • All sizes have one bottle mount in the front triangle
  • Replaceable derailleur hanger or SS insert
  • 142 x 12mm Maxle rear spacing
  • Can fit up to a 2.35” tire (tire size varies by brand, some tires may not fit)
  • Compatible with most standard 1x, 2x and 3x chainring systems.
  • Max 1x chainring size 32T with BioCentric II in rear position – Max 38T with BioCentric II in forward position

New ROS 9 ★★★★ X01 Star Builds
  • Frame: Niner ROS 9, Rally Blue
  • Fork: RockShox Revelation RCT3 Solo Air 130mm, 15mm, Rally Blue
  • Wheelset: NoTubes 3.30/ZTR Flow EX, 15mm Front, 142 x 12mm Rear
  • Tires: Schwalbe Nobby Nic Snakeskin TL, 2.35
  • Brakes & Rotors: SRAM Elixir 9 Trail, 180 / 160mm G2 Rotors
  • Brake Levers: SRAM Elixir 9 Trail, Black
  • R/Shifter: SRAM X01 11sp with Matchmaker
  • F/Shifter: N/A
  • R/Derailleur: SRAM X01 11sp
  • F/Derailleur: N/A
  • Cassette: SRAM XG 1195 11sp 10-42T
  • Chain: SRAM PC 1170
  • Crank Set: SRAM X01 GXP 32T
  • Bottom Bracket: SRAM GXP
  • Saddle: WTB Volt Race with Cr-Mo Rails, Niner Graphic
  • Seatpost: Niner Carbon Seat post, 400mm, Red, Niner Graphic
  • Handlebar: Niner Flat Top Alloy, 780mm, Red, Niner Graphic
  • Stem: Niner Alloy Stem
  • Grips: Niner Grrrips

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About the author: Francis Cebedo

The founder of mtbr and roadbikereview, Francis Cebedo believes that every cyclist has a lot to teach and a lot to learn. "Our websites are communal hubs for sharing cycling experiences, trading adventure stories, and passing along product information and opinions." Francis' favorite bike is the last bike he rode, whether it's a dirt jumper, singlespeed, trail bike, lugged commuter or ultralight carbon road steed. Indeed, Francis loves cycling in all its forms and is happiest when infecting others with that same passion. Francis also believes that IPA will save America.

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  • DS says:

    I do like the idea of an all-mountain (not Rally!) HT 29er in steel. But the writer suggesting this bike establishes a new category is disappointing and unfair to the many established (and quite good) current players on the market.

  • NV29 says:

    The Honzo came before the TransAM, also don’t forget 2Souls, and custom builders were doing these many years ago. To me this is more or less a copy of the Honzo, which I paid less than $400 for when it first came out. That said, this looks like a nice bike, albeit over priced and with too short TT.

  • Dan says:

    or the all mountain REEB – SS belt or chain, geared 2X10, True Temper OX Platinum Tubeing, made in USA.

  • edwin harvei says:

    Niner copies my Ragley Blue Pig that I built with my old 26″ components and 130mm Revelation fork for less than $400

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