The Bird Aeris 9 is a 160mm travel complete suspension 29er constructed out of aluminium. Designed, specced and put together in Britain.
It doesn’t appear that long earlier because Bird initially started with its 27.5in wheel Aeris, however in some way Bird is commemorating its tenth(!) anniversary in 2023. This Aeris 9 is not the ninth version of the Aeris. The 9 describes the wheel size, specifically 29in. Bird has something of an excellent track record among skilled mountain cyclists in the UK. Indeed, Bird was right up in the ‘most desired’ brand names in our recent reader study. It appears Bird bikes actually strike home with riders trying to find hard-riding, well-specced bikes without huge cost. And Bird understands how to make a bike appearance cool too. Which assists.
The Bike
The Bird Aeris 9, like the other 2 bikes in this test, is a 160mm travel complete suspension 29er constructed out of aluminium. Designed, specced and put together in Britain, Bird explains the Aeris 9 as an ‘All Mountain’ bike and I’m all for it. I’d much rather utilize the term All Mountain than something revolting like ‘Aggressive Trail’ (ugh). If you wished to advance up the ante, the Aeris 9 can be changed into a huge ol’ 180mm travel beastie through an optional linkage. Even if you were to never ever feel the requirement up your ante, it’s assuring to understand that the Aeris 9 chassis is constructed strong enough to deal with such rigours. Even simply sticking to the initial linkage, there is a flip chip in the Horst Link chainstay pivot area. Flipping it makes the bike 0.5° slacker, 7mm lower and 6mm longer (chainstay length).
The build set deserves going over. Partly due to the fact that this is a group test of mail order mtb. But partially due to the fact that it has an enormous result on the entire experience of riding this bike. Basically, the build set is best. Coil rear shock, Zeb Ultimate, Formula 4-pots, 200mm dropper, great grips, huge bars, brief stem, DHF ’n’ DHR II rubbers. The drivetrain is relatively yadda-yadda in my viewpoint. All SRAM and Shimano drivetrains work astonishingly when above base-level. But fantastic bits ain’t worth diddly squat if the geometry is ropey. The heading statistics here: 63.6° head angle, 77.5° seat angle, 486mm reach (size Medium–Long), 343mm BB height, 440mm chain stays. They all noise… area on. But how did it all trip?
The Ride
To begin with, the specification of this bike has a genuine impact on how it feels to ride. Basically, it is specced astonishingly well, with all the sorts of bits I’d like to see on my own bike. This produced a bike that took me no considerable getting-used-to duration. You can hop aboard the Aeris 9 and dive in. This is all assisted by the reality that the rear shock comes provided with a spring rate that fits your weight, and the set-up ‘cheat sheet’ on the back of the Zeb fork leg is practically bang-on to how it need to be established. Finding the rear shock a bit too bouncy up that very first climb? Flick the climb switch. Or, if you have couple of more seconds and understand your damping onions, dial on a couple of clicks of Low Speed Compression. I would warn about stopping the suspension’s flexibility too easily though since that back-end traction can get you up the most unbelievably questionable and high technical climbs up. As well as increased grip, the flexibility is simply that bit less back-jarring. You get far less battered throughout a flight. Yes, I am getting old. On smoother climbs up, I should admit to utilizing the climb switch. It includes the attendant threat of forgetting to disengage it at the top, however it’s great when you’re ugly-pedalling-tired. And there’s the placebo result too no doubt that includes snapping a switch for climbs up.
When it pertains to the sort of riding where you’re entering much deeper than the droop point, there is a truly great level of assistance at the back. As well as this assisting in regards to usefulness, like preventing pedal strikes, it implies the bike reacts actually enjoyably and usefully to guiding inputs and to pumping or working-the-trail for keeping or increasing your momentum. This isn’t a ‘soft’ trip that takes in all the kinetic energy entering a corner and leaves you having a hard time to return up to speed upon exit. You are still utilizing the travel available though. Geometry-smart, I actually like how the numbers collaborate. There is a flip chip in the chainstays and some riders might choose the much shorter setting (which likewise has steeper angles). however I am not a nu-skool manualling jibber. I partially choose the longer (and slacker) flip-chip setting. My wheels don’t frequently leave the ground. But they are on a regular basis heading some down something high and tight. Still, it’s great to have the flip chip there and, for when, the change is really considerable to the handling.
Overall
For something this metal-looking and coily, the Bird Aeris 9 is simple to ride quickly. It has exceptional speed, whether that’s when rising, coming down or passing through. The basic position of the bike is among stability. But that isn’t a euphemism for ‘boring’. The Bird Aeris 9 is wonderfully lively when you desire, or require it to be. It’s among those unexpected bikes that seems ‘aggro’ or ‘overkill’, however really ends up being a truly enjoyable overall mountain bicycle. The rear suspension, assisted in no little part by the really exceptional Formula coil rear shock, is adequately arranged. Supple and hoovery, yet remarkably encouraging and precise when it pertains to reacting to your intents. The lonnnng geometry numbers might get some discriminative individuals rolling their eyes, however the evidence remains in the path pudding and the Aeris 9 can put the miles in simply as well as it can get the smiles out.
Frame // Aluminium 6066, 160mm
Shock // Formula MOD Coil w/ Lightweight Spring, 230x65mm
Fork // RockShox Zeb Ultimate RC2, 170mm
Wheels // Bird Factory – Hope Pro4 centers, DT Swiss 29 E532 rims
Front Tyre // Maxxis Minion DHF 29×2.5in 3C MaxxTerra EXO TR
Rear Tyre // Maxxis Minion DHR II 29×2.4in WT 3C MaxxTerra EXO TR
Chainset // SRAM GX Eagle DUB
Drivetrain // SRAM GX Eagle 12-speed, 10–52T
Brakes // Formula Cura 4, 203/180mm
Stem // Bird 35 Stem 40mm
Bars // Big Bird Baw Bar 35, 800mm, 20mm increase
Grips // Race Face Getta Grip Lock-on
Seatpost // Bird Down Dropper V2.1, 200mm
Saddle // Bird Stork
BB // SRAM DUB
Size evaluated // M–L (Medium–Long)
Sizes available // Medium, Medium–Long, Large, Extra Large
Head angle // 63.1° / 63.6°
Effective seat angle // 77° / 77.5°
Seat tube length // 420mm
Head tube length // 110mm
Effective leading tube // 625mm
Review Info
| Brand: | Bird |
| Product: | Aeris 9 |
| From: | Bird Bikes |
| Price: | £3,990 |
| Tested: | by Benji for Singletrack World Magazine Issue 148 |
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