Exclusive First Look: Bird Goes To 29in Wheels With New AM9

September 15, 2017

Big news out of Swinley Forest this morning courtesy of Bird Cycleworks, which has just launched its first 29in mountain bike. Called the Aeris AM9, this guy is a 150mm travel full suspension bruiser built for eating all of the mountain, and probably getting involved in some of that new-fangled ‘enduro’ racing too.

Having previously been dedicated to the 27.5in wheelsize, the move to 29in wheels for this latest model is a big deal for Bird. But citing improvements in components such as lighter and stiffer wheels, and the availability of better quality 29in suspension forks, Bird is ready to leap into wagon wheel territory.

We’ve got some snaps of the latest pre-production prototype Aeris AM9, so lets take a closer look at what Bird’s cooked up for us.

bird aeris 29 am9
New prototype frame from Bird. And no 27.5in wheels in sight!

So it’s here, well nearly! We’re super stoked to open pre-orders for our new Aeris AM9, the new 29-inch full suspension platform from Bird Cycleworks. We’ve been working hard developing this new direction, and we’re finally happy to break our 650b exclusivity! The Aeris AM9 offers 150mm of rear travel, paired with 150 Yari or Pike up front for big days out” – From Bird Cycleworks.

bird aeris am9
Big Bird: The new Aeris AM9 features 150mm of travel and 29in wheels.

Bird AM9 Features

  • 29in full suspension all mountain bike
  • 6066-T6 heat treated alloy tubing
  • Four-bar suspension design with self-locking mini collet hardware
  • 150mm rear travel
  • 150mm fork travel
  • 65.5° head angle (static)
  • 76° seat tube angle (static)
  • 440mm chainstay length
  • 148x12mm Boost rear end
  • Clearance for up to 2.5in wide tyres
  • 1x specific frame design
  • ISCG05 chainguide mount
  • UK-friendly external cable routing (except for stealth dropper post)
  • 73mm threaded bottom bracket shell
  • Available sizes: Small, Medium, Large, X-Large
  • Frame RRP: From £1226 (including a RockShox Deluxe RT shock)
  • Complete bike RRP: From £2256
bird aeris 29er full suspension am9
The Aeris AM9 is the longest travel full suspension to come from the small UK mountain bike brand.

Suspension travel sits at 150mm front and rear, which makes this the longest travel offering currently from Bird. The small MTB-only company offers the 27.5in Aeris in both 120mm and 145mm travel options, so it would appear that Bird sees enough benefits of the 29in wheels to go the whole hog with the Aeris AM9 to give it even bigger boots.

The frame itself is built from hydroformed and heat-treated 6066-T6 alloy, which includes a stubby tapered head tube up front, and a nicely curved downtube that affords clearance to run a water bottle inside the front triangle. Pivot hardware is the locking collet variety, designed to keep the pivot bolts nice and snug.

bird aeris geometry
Aeris AM9 geometry.

Geometry is pretty kicked back, with the head angle measuring 65.5° (65° when sagged), and the bottom bracket sitting just 29.2cm off the ground when suspension sag is factored in. There will be four sizes on offer from Bird, including M, ML, L and XL, and each is built with a very long front centre. Reach is absolutely massive, ranging from 452mm for the smallest size, through to a gargantuan 522mm on the XL – pwoaar!

Having gone to Boost spacing on the rear with a 1x specific design, Bird has been able to open up tyre clearance for decent 2.5in wide 29er tyres. There’s usable mud clearance in there though, and part of that is the fact that the chainstays are on the more modest side, measuring at 440mm. Here’s the word from the Bird about getting chainstay length dialled in;

A word on chainstay lengths; some like it short, some like it long.  We like it balanced.  While super short chainstays can make a bike feel playful and easy to wheelie, they also shift your weight towards the rear axle, meaning you have to work harder to load up the front wheel during corners.  Really long chainstays provide stabilty at speed but also suck a lot of the fun out of riding and can make a bike handle like an oil tanker.  The Aeris AM9, like the 145, strikes a balance between stabilty at speed and sharp handling in the tight and twisties.”

bird aeris 29er full suspension am9
This Aeris AM9 is a pre-production prototype, but it’s very close to being ready. In fact, Bird is taking pre-orders right now.
bird aeris 29er full suspension am9
Four-bar suspension design uses a horst pivot just in front of the 148x12mm thru-axle dropouts.
bird aeris 29er full suspension am9
A solid hunk of alloy makes up the threaded bottom bracket shell and the main pivot. Note the fully external cable routing.
bird aeris 29er full suspension am9
The Aeris AM9 is designed around a metric rear shock, with a bearing eyelet for a smoother suspension feel.
bird aeris 29er full suspension am9
Low-profile tapered head tube.
bird aeris 29er full suspension am9
Designed in the UK. The frames are manufactured in Taiwan, and then complete bikes are ‘Built in the UK’.
bird aeris 29er full suspension am9
Digging the raw finish on this frame a lot.
 bird aeris 29er full suspension am9
The Bird Aeris AM9 will be available as both a standalone frame, and as a complete bike with several build kit options.

If you’re chasing more info on the Bird Aeris AM9, then head through to the Bird Cycleworks website for all there is to know. While this is a pre-production sample, Bird is taking pre-orders through its website, with production frames expected in February of 2018.

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First Look