For the last 6 months I have had the pleasure of riding the Bird Aeris AM, putting it through its paces on my local trails in the Tweed Valley, Scotland. The Aeris is a trail or enduro bike, depending on how you want to ride it, and depending on the shock linkage you go for. Originally launched in 2017 as the Aeris 145LT, the now rebranded Aeris AM 160 shares the same frame as the 145 but houses a different length linkage on the horst 4-bar suspension platform.
Why the rebrand, you say? Bird found that the vast majority of customers were opting for the longer suspension linkage, giving them that extra 15 mm of rear wheel travel. The extra travel comes concomitantly with a slightly lower bottom bracket and a slightly slacker head angle.

As this is a long-term review piece, let me tell you about the terrain the Bird has been subjected to. The Tweed Valley, home to two of Scotland’s 7Stanes Mountain Bike Trail Centres, and plethora wild trails, is renowned for its loamy, ultra steep terrain (-35% average gradient not uncommon). Though this wasn’t by any means the harshest winter I’ve seen in Scotland, the Bird has still been subjected to snow, hail, mud, grit and, very briefly, dust. I’m happy to say that after 6 months of riding the Aeris, the pivot bearings still feel as smooth as they did on day one, with no identifiable play in the system.
Bird Aeris AM 160 Mountain Bike
The Bird Aeries isn’t a new bike; it has been around since 2017 and, with the success it has seen in the UK, it is likely to be around for quite some time. That, and its unquestionable value for money, this bike is certainly deserving of a closer look. On the topic of value, Bird have just released 5-year Anniversary editions of the Aeris and Zero AM hardtail, featuring the new SRAM SX Eagle 12-speed 10-50T groupset. I tested the Aeris in both 145 and 160 versions, opting to switch for the longer and slacker 160 after just a few rides on the 145 – not because I didn’t like the 145, but because I thought a lower, slacker and longer travel bike to be more appropriate for the terrain.
On the Aeris 145, the suspension platform is designed to be slightly regressive initially, for small bump sensitivity, until the sag point at which it then becomes progressive and more supportive. The 160 linkage changes the suspension kinematics to be more linear through the initial part of the stroke, becoming rapidly more progressive beyond the sag point. I’m told the more progressive Aeris 160 geometry is much more suited to coil shocks than the Aeris 145. Ben, the founder of Bird opted for the Horst 4-bar suspension platform simply because it is most easily tuned for optimisation of the 4 most important suspension characteristics; anti-squat, leverage ratio, pedal kickback, and anti-rise.

The Test Spec

Riding the Bird Aeris AM 160
The Bottom Line
Customisation
Sizing & Availability

