Chris on National Trail in South Mountain. The test track!
The Firebird comes in three sizes – small, medium and large. The 6061 oversized aluminum frame is proven strong and light. The unified rear triangle is connected to the frame via the carbon upper rocker at the top and DW link at the bottom. The shock is connected to the upper carbon rocker and the lower DW Link. This creates a full floater shock resulting in a more variable shock rate which adds to the plushness of the suspension. The DW Link features oversize pivot axles rotating on 8 cartridge bearings. The rear triangle is stiffened via the vertical tubing connecting the seat and chain stay. This provides a unique look to the frame as well as using enough material to keep the bike light but stiff.
To convert the 26in Firebird frame to be 27.5 compatible Pivot created an angled head set to maintain the slack head angle with the larger diameter wheels. In fact the 27.5 Firebird is one degree slacker then the 26in Firebird. The larger wheels also create a greater forward rake which also aided in stability. The 27.5 fork and wheels fit the frame with no modifications. The bike could also (barely) accommodate Schwalbe Hans Dampf tires which are the current largest 27.5 tires in production.
Other observations follow:
- The geometry biases this bike for speed. 44.3inch wheelbase with a 2014 Fox Float 34 CTD Kashima Fork, 17.25 chainstay, slightly higher 14.1inch BB Height and slack head 66o and seat angle (71.5). The low standover (28.75in) aids in its nimbleness.
- The 30.9 seat post size can accommodate the Rock Shock, Gravity Dropper, Kind Shock, Command Post and Joplin adjustable seat posts. This Firebird had the KS LEV Dropper post with the integrated cable and remote thumb lever. Very easy actuation and quick up and down action. The bike comes with a custom valved Fox CTD or DHX Kashima shock. The rear axle is 12X142mm for maximum stiffness.
- Another unique feature on this bike is the floating front derailleur. Designed to move in line with the rear axle to keep the chain in line to ensure consistent shifting performance. I found this feature to result in a lot of clanging on rough terrain, this was rectified with the MRP LRP 2X chain guide.
- 1.5 inch head tube is designed to accommodate a 160mm or 170mm fork. The Firebird 27.5 comes standard with at Fox Float CTD 160 24 Kashima fork.
- The rear drop out is shaped to accommodate the CNC’d derailleur hanger. One of the finer touches on the Pivot bikes.
Open slickrock slopes.
The 27.5 Firebird maintained the same ride characteristics as the 26in bike. You would not know you were riding a bike with a bigger wheel size unless you were told, or saw the number on the tires. Each pedal stroke provided more forward momentum to move over obstacles and through rough terrain. While climbing each pedal stroke moved you that much further allowing you to go very slow in technical terrain but move fast enough to maintain your balance. Even in loose rough chunder the front tire was not easily deflected. The bike is plush and the suspension very responsive. As long as I maintained a stable riding position the bike plowed over and through the terrain. It almost made riding too easy! The only noticeable difference was how much faster you are then your friends.
On smoother terrain the bike just wanted to go faster. The rear triangle was stiff in corners and over rough terrain resulting in smooth consistent tracking. The bike only used the suspension it needed or what you brought out of it.
I found the higher bottom bracket on the 27.5 resulted in fewer pedal strikes than what I would get riding in our home rooty rocky terrain.
The 23 inch cockpit was comfortable for climbing and descending for my 5’9″ frame. The slack head angle was noticeable on longer climbs as it puts you in a more upright position. The slacker 71.5o seat tube angle would also contribute to this position. If you are a rider that doesn’t like slack climbing geometry you may be uncomfortable climbing on this bike. The 28.75 inch standover made riding slow technical trail sections more comfortable.