While we've been known to rip some gnarly trails on a cyclocross rig and bask in the adrenaline rush of simply surviving with life and limb intact, we'll readily admit that sometimes a little bit of squish would make the ride a lot bit better. For those of us that love to ride fast and revel in the challenge of nimbly picking through technical, rocky sections that full suspension whips plow indiscriminately through, Niner drops the 2017 Air 9 RDO Mountain Bike Frame. With a Boosted rear axle spacing and tweaked geometry, this hardtail is ready to shred. The most notable changes include a lower handlebar height, giving the Air 9 a nudge towards the venerable RKT 9 RDO's aggressive positioning. Paired with a longer cockpit and slacker head tube, this makes for a frame that handles deftly on knife edge lines and jumps the second you need it to. Compared to the previous Air 9 the chainstays scrunched in by 4mm to 435mm for lightning fast acceleration and nimble handing without crossing over into jumpy, squirrely territory. The new Air 9 RDO also sizes down its seatpost diameter to 27. 2mm to take advantage of that little bit of extra flex and resulting comfort found in a narrower post. Out back, this year's model now boasts another different dimension namely, a 12 x 148mm Boost axle width, keeping it in line with current trends for wider hubs and stiffer wheelsets. Niner also tucks the brake caliper mounts on the chainstay, neatly within the rear triangle. This makes sense from a frame building standpoint, as the seatstay is generally the burlier of the two rear stays and the placement protects the caliper somewhat in the event of a crash. We also think that particular placement just plain looks better than an ungainly bump hovering above a seatstay. As with Niner's other RDO offerings, the Air 9 RDO is constructed using Niner's Carbon Compaction System CCS, which gives Niner complete control over tube wall thickness across the frame. This makes for tube walls ...