Firebird Carbon 29 Pro XT/XTR Mountain Bike
If your dream ride consists of barreling through high-speed rock gardens on a 3,000-foot descent, slapping berms and hitting jumps in the bike park, or setting your fastest time on a gnarly enduro stage, we can think of a few bikes that'll fit the bill. Now imagine it being lightweight and efficient enough to be able to climb to the top and handle twisty flow trails without sacrificing the poppy, lively feel that makes those types of trails fun. That narrows the playing field significantly and the one that'll continue to ride to the top is the Pivot Firebird 29. Big wheels meet 162mm of supple travel, and in conjunction with modern long and slack geometry, your confidence is about to get a major boost as you charge down steep, burly lines and high-speed chunder. And while this Firebird is no XC whippet, the speedy 29-inch wheels and efficient DW-link suspension can rack up the backcountry miles better than most bikes in its category. Additionally, Super Boost Plus allows Pivot to build super short chainstays for a nimble ride and afford huge clearance for 29er tires (up to 2.6in), or go 27.5+ if you're looking for the ultimate in traction.
The Firebird 29 borrows heavily for the design and geometry queues of the 27.5in Firebird and its Phoenix DH Carbon siblings, with long reach numbers and 45mm length stems across the board. The Firebird 29's super-short chainstays sit at 16.96-inches, thanks to the 12 x 157mm Superboost Plus spacing allow for snappy handling, quick power transfer, and easy lifting of the front wheel up and over techy climbs, and for those blessed with the talent—manualing. Also contributing to the climbing chops are its steep seat tube angle of 74.5 to 75-degrees (based on its adjustable flip-chip position and lower headset cup selection), which places you right on top of the pedals and prevents the front wheel from wandering on steep switchback climbs while its adjustable 65.5 to 65-degree headtube angle lengthens the bike's wheelbase for excellent stability that gets better the faster you rip down notoriously steep, gnarly terrain. Growing the wheelbase and getting the front wheel too far out in front of the rider has diminishing returns if you can't properly weigh the front tire for proper traction, so Pivot specs a fork with a 44mm offset that allows you to reap the benefits of a slack head tube while getting the front wheel a little closer to the steering axis. Also, the headtube accommodates an optional 17mm lower headset cup that is beneficial when swapping between wheel sizes or further fine-tuning the bike's geometry.
As with all of Pivot's full-suspension frames, this Pivot Firebird 29 receives the much-lauded DW-link suspension platform. Two things you'll really be looking for in a bike that is sporting nearly 6.5-inches of travel are supple stroke and efficient pedaling and the DW-link provides both in spades. You'll find its travel is plush off the top and feels very linear, almost coil-like, with plenty of ramping at the end stroke so you don't blow through the travel while also providing plenty of support to reduce the dreaded mid-stroke wallow. This way, you can pedal in a manner that you've never experienced on a 160+ millimeter bike. DW-link also affords a fully active suspension, even under braking, and unlike some designs, it doesn't get hung up on square-edge hits, which allows you to plow up and over ledgy rock faces and rooty terrain without losing momentum and requiring you to dismount in shame. Spring and damping duties are handled by FOX's Factory Float X2 shock and join the Phoenix DH-inspired upper and lower links, which are super wide and beefy. Also, these beefier linkages tie together the dual-upright swingarm supports, thus adding impressive amounts of frame stiffness and durability. Also worth noting is the flip-chip on the upper link doesn't affect the shock rate, so you can dial in the geometry for the riding on tap without having to fiddle with your shock settings.
We made mention of the rear dropout spacing above and we think it's worth mentioning again for those unfamiliar and even for those that are—mainly because there are plenty more bikes in the pipeline that will soon be sporting Super Boost Plus spacing. The wider axle spacing allows the hub's flanges to push further out, thus helping to even spoke tension on either side of the rear wheel. Furthermore, the improved bracing angles build up a 30% stiffer rear wheel. The other added benefit of the wider rear end spacing lies in the shorter chainstays that still play nice with wider rubber. You might be thinking that the wider dropout spacing splays the chainstays out further and it becomes an easier target for heel strikes. This would be true, but Pivot addresses this with chainstay shaping that swoops out of the way with clever indentations exactly where your heels would rub. In fact, we can attest on a recent ride in Moab that we experienced zero interactions with the Super Boost Plus chainstays despite using the same pedal and shoe combo and getting the occasional strike on our non-Super Boost Plus rigs.
Balancing the build with materials that can handle the terrain, the Firebird 29 is crafted from a painstakingly precise mix of composite fibers and resin, then meticulously laid to create a frame that finds the happy medium of strength, stiffness, and weight. The chassis itself benefits from Pivot's hollow-core internal molding process for uniform, controlled wall thicknesses and material distribution. This process virtually eliminates inconsistencies and resin pooling, increasing structural integrity while targeting areas for weight loss. Simply put, it's the best way to make a strong and lightweight carbon fiber frame.
Pivot works closely with its component partners for its build kits and it results in a better complete bike that utilizes the latest technology and packs in a ton of value. This Firebird 29 Pro XT/XTR build gets the FOX Factory X2 shock that soaks up trail chatter and big hits with aplomb. It's highly adjustable and tuned specifically for the DW-Link's kinematics, and has two settings so you experience a bottomless feel when bombing descents, and at the flip of a switch, a firmer mode offers support up the fire road climb so you can do it all over again. Up front, the FOX 36 Factory fork's burly chassis and oversized stanchions offer sure-footed tracking through ruts, roots, and bombed out braking bumps. Other features include a mix of Shimano XT and XTR 12-speed drivetrain components, offering the range we're after on those long days with plenty of climbing with enough overdrive so we're not spinning out on the way back down and we always have the right gear for all of the ridgeline riding in between. This build also gets Shimano's 4-piston XT brakes which offer top-notch power designed to quickly halt an e-bike—and with modulation to boot. The DT Swiss M1700 wheelset has a 30-millimeter inner width to plump up the Maxxis Minion rubber that works so well across different terrain and Pivot even upgraded its stock 18t star ratchets for 36t for quicker engagement that we're sure is valued for the techy riding close to its Tempe, AZ home base. And since Pivot knows they built this bike for a rowdy crowd, scuff-guards are included on the downtube/bottom bracket area and drive-side seat and chainstays so your carbon frame stays well protected, looking like new, and is quiet as you up your game deep in the woods, desert, or in the bike park.
- Long-legged 29er that cleans climbs and devours descents
- Redesigned frame and linkage is remarkably strong and stiff
- Slack head tube and long reach builds confidence on descents
- 74.5 to 75-degree seat tube angle for optimal climbing position
- 162mm of bump-taming DW-Link suspension still pedals efficiently
- Precision hollow-core carbon sheds grams and boosts strength
- Super Boost rear spacing accepts both 29in and 27.5+ wheel sizes
- FOX X2 shock and 36 fork offer glued-to-the-ground traction