UK-based brand Bird has updated its Aeris 9 enduro bike with a new frame allowing up to 180mm of travel at each end.
The frame will come as standard with 160mm of bump-eating travel and a bias towards descending performance. However, Bird will be offering an aftermarket linkage, which will bump up travel to a super-enduro style 180mm.
This is all backed up with a new tubeset that allows the use of 180mm forks, whether you're running 160 or 180mm of travel out back.
To ensure the Aeris 9 is up to the task, it's been hidden in plain sight under Bird riders Liam Clement (EWS U21 racer) and Tomas Kupstys, as they've claimed numerous domestic podiums.
Bird Aeris 9 frame details
While Bird offers a carbon version of its Aether trail bike, it stuck with aluminium for the construction of the Aeris 9.
Bird says that while the bike is designed for enduro use, it has finely tuned the anti-squat to keep it pedalling well, while also giving each size unique seat tube angles to ensure rider weight distribution is kept in the right place, regardless of how tall (or short) the rider is.
On top of a linkage that changes the travel, there is a flip chip in the rear triangle to adjust geometry. This adds 6mm to the chainstay, slackens angles by 0.5 degrees and reduces the bottom bracket height by 7mm.
Those running 160mm forks will get an even more slacked-out shape with the chip flipped, while those with 170 to 180mm forks will see the BB height returned to figures similar to a 'standard' 160mm-fork Aeris, but with an even longer and slacker bike.
The frames offer the ability to run cables internally, for a cleaner look, or externally, for those who want an easier maintenance schedule. Cables aren't run through the headset, because Bird says "we don't hate you".
The four-bar suspension system has oversized main pivots, running double-lipped bearing covers to reduce dirt and water ingress and prolong their life.
Other frame features include a SRAM UDH, a threaded BB, space for 29x2.6in mountain bike tyres and room for a 'good-sized' bottle in the smallest frame, even while using a piggy-back coil shock.
Raw aluminium, 'Jet Black' and 'Blurple' (a flip-flop blue/purple paint) will be offered.
Bird Aeris 9 geometry
Bird has long been a purveyor of long and slack bikes, and this remains the case with its latest enduro sled.
Bird will offer the bike in four sizes, from medium to extra-large (with a medium-long being the size you might not have guessed). This covers riders from roughly 168 to 193cm tall.
| 160mm fork / 440mm chainstay | Medium | Medium-long | Large | Extra-large |
|---|---|---|---|---|
| Effective top tube (mm) | 600 | 625 | 650 | 675 |
| Reach (mm) | 457 | 486 | 515 | 544 |
| Stack (mm) | 618 | 627 | 636 | 645 |
| Seat tube (mm) | 395 | 420 | 445 | 470 |
| Head tube (mm) | 100 | 110 | 120 | 130 |
| Wheelbase (mm) | 1,230 | 1,263 | 1,296 | 1,330 |
| Chainstay length (mm) | 440 | 440 | 440 | 440 |
| Standover (mm) | 670 | 674 | 679 | 682 |
| Effective seat tube angle (degrees) | 77 | 77.5 | 78 | 72.5 |
| Real seat tube angle (degrees) | 72 | 73 | 74 | 75 |
Bird Aeris 9 range information
Bird has long been happy to offer customers the ability to custom-spec their bikes from a wide range of suppliers, including suspension from the likes of Fox, RockShox, Formula, Cane Creek and Fast.
The brand has its own line of hand-built wheels, and on stock bikes, takes care to pick components that give the best bang for their buck – for example, using Shimano's XT shifters on Deore-spec bikes, in light of the improved performance this upgrade gives in the real world.
Bird says it's happy to ensure colour matching between seat collars, hubs and headsets, and will even chop your bars down to your required width should you wish.
As such, there aren't many set models.
However, frames start at £1,295 and bikes can be built for as little as £2,870. Bird offers 0 per cent finance over 24 months.
Bird's suggested build at £3,875 looks like exceptional value:
- Bird Aeris 9 frame
- RockShox Lyrik Ultimate 180mm
- RockShox Super Deluxe Coil Ultimate shock
- SRAM GX Eagle drivetrain
- SRAM G2R brakes
- Bird Factory wheels
- Maxxis Assegai tyres
- Bird/Race Face finishing kit
Though Bird is a direct-sale brand, it works closely with The Bike Bothy, which has shops at Laggan Wolftrax and Pitfichie in Scotland, where models can be seen.
Bird's own showroom is at Eversley in Hampshire, while it will also have a demo fleet at Glencoe Mountain Resort (lift-assisted).
Further demos will be at the Scottish Enduro Series round in Pitfichie from 3 to 4 September, Laggan Wolftrax from 9 to 11 September and at the Tweedlove Festival from 16 to 18 September.
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