Obliterate every line.
It's pretty darn difficult to ignore the current crop of hard-hitting 29ers that have come to dominate the enduro and gravity spectrum of the market recently. Aggressive trail riders and enduro racers are finally catching up to what cross-country racers have known for years, which is that larger 29-inch wheels cover far more ground and decimate rocks and roots standing in their way, due to the larger wheels offering a superb angle of attack and faster rolling speed than their 27.5-inch brethren. However, it's taken a bit longer for bike manufacturers to dial in the geometry numbers and maintain the high levels of stiffness you've come to associate with smaller wheeled bikes, especially if you're a demanding rider. That being said, the folks at Pivot have dialed in the Firebird Carbon 29 Race XT Complete Mountain Bike for aggressive riders that skew towards the gravity end of the riding spectrum and demand the faster rolling speed and line-obliterating force of larger 29-inch wheels, but without drastically inhibiting the bike's ability to pedal back up for another grin-inducing lap or even pedal lengthy distances across formidable alpine terrain.
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 tend to hang up on square-edge hits—allowing 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 metric DPX2 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 Superboost 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 own personal non-Superboost Plus rigs.
Pivot realizes that building a great bike requires a holistic approach and all the components on its builds are very similar to ones we would select if we were building the frame from the ground up. This Firebird 29 Race XT build gets the FOX Float DPX2 shock to soak up trail chatter and big hits. It's tuned specifically for the DW-Link's kinematics, and has three settings so you experience a bottomless feel when bombing descents in Open mode. You can then flip the switch and choose either a Medium or Firm mode to reduce excessive rear end motion on those smoother fire road climbs and asphalt rides back to the trail head. Up front, the FOX 36 Performance fork's burly chassis and oversized stanchions offer sure-footed tracking through ruts, roots, and bombed out braking bumps.
Other notable features include a mix of Shimano's XT and SLX drivetrain bits, offering plentiful range for all-day climbs and scorching descents while emphasizing smooth-shifting reliability for years to come. We like Shimano brakes and so does Pivot, so this build bucks the trend of outfitting the competition's brakes with its Shimano SLX levers and calipers offering high levels of power and modulation without the higher price tag of XT brakes. A Sun-Ringle Duroc wheelset with 30-millimeter inner width plumps up the Maxxis Minion rubber that works so well across different terrain and trail ecosystems. Finally, the Firebird 29 is given another callback to its Phoenix roots with the finishing kit that includes its shorter 170-millimeter cranks to prevent rock strikes, a properly wide 800-millimeter alloy bar, 35mm clamp stem for added security, and cushy Padloc grips. 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 to keep your bike looking and riding like new.
- Long-travel 29er that decimates descents, yet still cleans climbs
- Redesigned frame and linkage is remarkably strong and stiff
- Slack head tube and long reach for confidence at higher speeds
- 74.5 to 75-degree seat tube angle for optimal climbing position
- 162mm of hit-taming DW-Link travel that still pedals efficiently
- Precision hollow-core carbon layup for superb strength-to-weight
- Super Boost rear spacing accepts both 29in and 27.5+ wheel sizes
- XT/SLX 1x11 drivetrain for crisp, reliable shifting across a wide range