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  • Niner - SIR 9 27.5+ 2-Star Complete Bike - Slate Blue/Orange
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  • Niner - SIR 9 27.5+ 2-Star Complete Bike - Slate Blue/Orange

Niner SIR 9 27.5+ 2-Star Complete Bike


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    SIR 9 27.5+ 2-Star Complete Bike

    There's a very good reason why many custom frame builders use steel to this day. Premium steel alloys, like Reynolds 853, are revered for their strength and ability to add a springy, lively ride. When you put that material in the hands of the mountain bike maestros at Niner, you can bet you'll get modern trail geometry, the ability to run 27.5+ or 29-inch wheels, and a bevy of mounting points for bikepacking adventures. So if you're looking to get back to your steel hardtail roots or a new riding buddy for all-day and overnight adventures, the SIR 9 27.5+ 2-Star Complete Bike gets you simplicity, strength, and unmatched versatility. We love the ability to run the voluminous plus tires in this configuration for flotation and grip over loose and chunky terrain and with a simple wheel swap, you can change the ride to momentum-carrying 29er wheels for maximum roll over and mile munching.

    As mountain bikes continue to evolve, Niner took it upon itself to modernize the SIR 9's geometry into something a little bit more trail-oriented. Niner's [R]evolutionary trail geometry makes the SIR 9's reach a bit longer while shortening the chainstays for snappy handling on tight trails and more stability with its roomier cockpit, giving it more composure up and down the trail and at high and low speeds. The slightly longer wheelbase inspires confidence on steep, rough downhill portions of the trail allowing you to ride terrain typically reserved for full suspension bikes.

    Up front, a RockShox Judy Gold RL Solo Air fork with 120-millimeters of travel gobbles up the terrain and kicks the head tube angle to a very trail-worthy 68-degrees. This provides the chops to attack fast descents and technical sections with more confidence than typical XC hardtails. That slackness up front doesn't sacrifice its pedaling and climbing ability though, as Niner designs it with a steep 74-degree seat tube angle, which places you in an optimal pedaling position.

    If you didn't know it by now, SIR is an acronym for "Steel is Real," so it only makes sense that the SIR 9 receives its construction from steel which yields that smooth, compliant ride over jarring sections of trail. So when picking which steel alloy to use, Niner went with the best, Reynolds 853, well renowned for its supple ride quality and high levels of strength. Reynolds 853 steel is heat treated and air hardened, meaning the weld zones actually increase in strength after cooling, making them impressively resilient to the stresses and rigors of trail riding. Inside the frame, Niner places hidden inner-plates stiffening and strengthening the frame's integrity—all without compromising the steel frame's compliance and supple feel.

    This 2-star build packs a ton of value and comes with the massive gear range of SRAM's NX Eagle 1x12 drivetrain, and with its wide-ranging 11 to 50 tooth cassette eliminates the weight and complexity of a front derailleur with its wide gear range. It rolls on Niner Alloy wheels and Maxxis tires which we've had great luck with both in the dependability department.

    • Niner's versatile steel hardtail with plus wheels
    • Reynolds 853 steel adds compliance for smoother ride quality
    • 27.5+ version provides greater speed and obstacle rollover
    • Progressive geometry for lively handling and long-distance comfort
    • Boost axle spacing accepts 29x2.5 and 27.5x3-inch tires
    • 18 total mounts enhance carrying capacity for bikepacking
    • SRAM NX Eagle drivetrain provides a wide gear range
    • RockShox Judy fork provides 120mm of terrain-smoothing travel
    • Item #NNR00AA

    Tech Specs

    Frame Material
    Reynolds 853 Steel
    RockShox Judy Gold RL Solo Air
    Front Travel
    Niner ZS
    SRAM NX Eagle
    Rear Derailleur
    SRAM NX Eagle
    SRAM NX Eagle DUB
    Chainring Sizes
    Bottom Bracket
    Bottom Bracket Type
    SRAM PG 1230
    Cassette Range
    11 - 50t
    SRAM NX Eagle
    SRAM Level
    Brake Type
    hydraulic disc
    SRAM G2CS [front] 180mm, [rear] 160mm
    Race Face Aeffect R
    Handlebar Rise
    Handlebar Width
    Niner Grrrips lock-on
    Race Face Aeffect R
    Stem Length
    Niner custom, Cr-Mo rails
    Niner Alloy
    Niner Alloy
    Front Axle
    15mm Boost
    Rear Axle
    12 x 148mm
    Maxxis Rekon + DC/EXO/TR
    Tire Size
    27.5 x 2.8in
    not included
    Recommended Use
    cross-country, trail
    Manufacturer Warranty
    5 years on frame

    Tech Specs

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