Niner

Jet 9 RDO 27.5+ 5-Star X01 Eagle Complete Bike - 2017

The 2017 Jet 9 RDO 27.5+ 5-Star X01 Eagle Complete Bike celebrates Niner Bikes' foray into the brave new territory of 27.5+ wheels with top-tier componentry and updated geometry that pushes the Jet 9 closer to all-mountain aggressiveness. Pairing a longer top tube, slacker front end, steeper back end, and 20 extra millimeters of Continuously Varying Arc (CVA) travel with the plush traction of 27.5+ tires makes this bike one formidable trail machine. Along with that reworked geometry, 2017 also marks the first time a 27.5-inch wheel has graced a Niner frame. Although given the similarity in circumference between 29-inch wheels and 27.5+ donuts, it isn't that far of a stretch to see why Niner went for it.

This Jet 9's dreamy build kit centers on ENVE's M60 Forty+ HV wheels and SRAM's shiny new Eagle X01 12-speed drivetrain. With the addition of a 50t granny cog, Eagle is like a gift of salvation from on high when you find yourself grinding up a steep climb, out of gas, out of mettle, but not yet out of the woods. And while the X01 version may not have the golden glow of XX1, Niner's new Jet 9 colorways more than make up for any lost bling.

As with most bikes in the current trail generation, the key element influencing the new Jet 9's versatile geometry is its Boost rear axle. Bumping the spacing up to 148mm lets Niner chop 21mm off of chainstays by slamming the rear wheel up into the seat tube. The extra clearance also allows for 3in tires on 27.5 rims, which equates to more traction across root-latticed trails and some extra cushion when the terrain gets chunky. The steeper seat tube keeps you centered over the pedals for more efficient climbing while the included dropper post allows you to clear out some cockpit space so you can throw the bike around on descents.

The 27.5+ Jet 9 also includes a deeper fork, running 140mm instead of the 29er model's 130. This keeps the geometry relatively in line across wheel sizes, though the 27.5+ version does shed an extra half degree in the head tube to move the 27.5+ Jet 9 that much closer to enduro rowdiness. It also pairs nicely with the new iteration's longer reach and shorter stem, making for a bike that can ride roughshod across all manner of trail furniture without sacrificing responsive steering. Slack head tubes are fun, but we're occasionally frustrated by their muddy responsiveness. The Jet 9 lives up to Niner's reputation of nimble, big-wheeled machines by applying that ethos to the mid-wheel range and ensuring that enduro aggression doesn't come at the cost of control. We like rolling roughshod over terrain, but we also like the challenge of dicing rock gardens apart. The Jet 9 satisfies that craving.

Despite the above changes, Niner's Race Day Optimized (RDO) construction process remains relatively unchanged. This is a good thing, as Niner's compaction method presses out any excess resin and compacts the carbon down to a uniform wall thickness. This gives Niner precise control over where material placement, letting the engineers reduce weight where it's not needed while ensuring stiffness and durability at key areas of power transfer and abuse.

The CVA suspension model is also virtually unchanged. CVA is designed specifically around 29in wheels to keep the big-rim platform balanced between taut and supple. Since there's little difference in the dimensions between 29 and 27.5+ platforms, it translates well to donut-tire models. CVA's low compression ratio means there's less need for suspension preload, so the mechanism can float more freely and react more readily to the terrain without being loose or sloppy. The lower linkage's placement beneath the bottom bracket isolates pedal input from suspension action to prevent the system from bobbing or back-kicking, resulting in a smooth but efficient ride that's responsive to both your power and the terrain.

The frame's finishing details are everything you'd expect from the obsessive developers at Niner, and our favorite new addition is the inclusion of a BSA threaded bottom bracket. PressFit shells may be lighter and more convenient, but the exact tolerances of a CNC-machined thread are virtually unsurpassable by today's composite technology. The threading means bearing cups install perfectly, reducing wear over time and eliminating the creaks, groans, and pops that so often accompany PressFit models. Vulnerable bits are girded with titanium protection plates. The frame also includes integrated battery storage in case you get the urge for electronic shifting, and the revised axle spacing and geometry dimensions accommodate 29er tires up to 2.5in and 27.5 tires up to 3in.