In the churn of new, ever beefier axle-widths and the explosion of plus-size tire popularity, one could say we’ve seen about every possible combination of the two over the past couple of years. Given Pivot’s penchant for pushing the boundaries, though, we shouldn’t be surprised that they’ve taken the plus/Boost combo a few millimeters further with the 2017 Pivot Switchblade Carbon 27.5+ XTR 1x Complete Mountain Bike. Kitted up with Shimano’s top-tier XTR componentry, a KS LEV dropper, and snappy Reynolds carbon hoops, the Switchblade enjoys expanded frame clearance and trail-smoothing squish to redefine what’s possible.

There’s a lot going on with this bike, and we’ll get to it all eventually, but the key element lies in the introduction of what Pivot is calling Super Boost Plus 157, which is a new rear axle standard that adds an additional 9mm to the rear axle and 12mm to tire clearance. It essentially combines a DH chainline with a typical 5in bike’s Q factor and heel clearance. The introduction of a gravity-sized rear axle has serious implications for an aggressive enduro rig, and these implications go well beyond the increased rear wheel stiffness of the more acute spoke angle.

The key effect of the Super Boost rear hub is that the Switchblade enjoys the clearance to run traditional 29ers or, as is the case here, add an additional element of forgiving, save-your-butt squish with 27.5+ wheels and tires. Either way, the extra-wide spacing allows Pivot to get freaky with chainstay lengths, chopping them down to 16.85in by moving the rear wheel up towards the seat tube. That’s a dimension that makes standard Boost axles blush, and it pairs with a Phoenix-inspired, double wishbone rear triangle to stiffen both the pedaling interface and the linkage design.

The rest of the geometry is similarly capable. Where the concise back end makes for a sharp knife while dicing rooty sections, the enduro-minded head tube and bottom bracket height make for a slack, low chassis that complements the 2.8in tires with a devil-may-care attitude in the face of questionable lines. The Switchblade provides a platform of stability when a series of poor life choices on the trail has you confronting big hits and roll overs at impolitic speeds. Despite the frame’s big-line parachute qualities, its seat tube sits relatively steep, keeping you forward and on top of the pedal stroke while climbing. It’s a little slacker than the Mach 4, but—when the grade flips and the rocks rise to meet you—the Switchblade will leave any XC race whip in the dust.