The burly Bird catches the berm

Product Overview

Bird Aeris 145


  • Sitting on the Aeris and feeling at home on the size large.


  • Bamboozled by spec options.


Bird Aeris 145 first ride


Price as reviewed:


The Bird Aeris 145 is an enduro machine with 145mm travel with modern geometry and sizing. This is a big, slack bike for tall as well as short riders.

Bird Aeris 145 need to know

  • Direct sales brand Bird’s latest bike, and enduro machine with 145mm travel.
  • Multitude of spec options that lets you customise pretty much everything.
  • Modern geometry and sizing make this a big, slack bike for tall as well as short riders.

bird aeris

You probably know all about the likes of YT, Canyon and Radon, the German direct sales brands cutting out the middleman and bringing us bikes straight from the assembly room. The UK has a few too, with Hampshire-based Bird offering two full sus bikes and two hardtails, all with massively customisable spec and all at the kind of direct market prices we’ve come to expect.

bird aeris

6066 alloy frame can be specced with an array of componentry

Bird Aeris 145 first ride

The Aeris 145 here is the newest and burliest bike Bird makes, with 145mm travel and a choice of 150 or 160mm suspension fork. That’s just the beginning of your choices though, you start with a frame and Bird hits you with an abundance of options to build it up, from the six drivetrain builds to the amazing 10 tyre options. This goes some way to explaining the huge variation in price between models, which start at £2k for a basic Aeris 145, although this particular bike built up just the way we like it, with Maxxis tyres, wide bar, short stem and Eagle drivetrain costs a grand more. It’s quite nice to know there probably isn’t another exactly like it anywhere.

bird aeris

Rear suspension offers 145mm of travel with three shock options

Back to the frame then, the bones of the Bird, and the Aeris 145 is a big bike. And we mean big — there are five sizes to pick from, with the biggest taking in a massive 528mm reach and long 1282 wheelbase. To put that in perspective, that’s more room in the cockpit than the giant Pole Evolink 140 we tested last year. Perhaps more telling, I was able to choose the smaller size Large, rather than opting for the biggest bike on offer, as is so often the case, and it leaves somewhere for taller riders to go. This is one agile bird, not tied to model years or big company slow-motion thinking.

bird aeris

SRAM Eagle cassette and Boost 148 back end

The Aeris isn’t a completely new bike, but this new version has changed somewhat, with an extra 5mm of travel, a new tubeset made from stronger 6066 alloy, and self-locking mini-collet axle bearings. That’s not all, there’s a new one piece hollow section yoke and Boost 148 back end, and of course its single ring specific. There’s no internal routing but that’s because Bird says riders don’t want the faff of threading cables and hoses through the frame. We think they’re right, riders don’t want the faff but we do appreciate it when bike companies do that job for us.

bird aeris

Roomy cockpit will suit rangy riders

I hate to bang on about this, but jumping on the Bird just feels right, it’s such a roomy, comfortable and solid place to be. They’ve got the geometry spot on. It pedals like something else too, it’s a fairly light 30lb in weight but it flies up the hills with every ounce of your leg power pushing you up the hill. It’s going downhill that the Aeris gets a little confusing. With 145mm of travel the bike should fly through rough stuff but I found myself clattering through trail litter, riding slow and getting dropped. Despite running 35% sag I was barely getting half the available travel, and there was none of the pop and playfulness I like in a trail bike. Winding off all the rebound helped liven the bike up a little, but with nothing to hold the back end down, drops became a nervous affair.

Bird offers a choice of three shocks, so I asked for an upgrade to the Super Deluxe RCT — it’s a piggyback shock so it should help the bike feel plusher, I figured. Again, the bike felt overdamped, but with the posh Super Deluxe at least I had the chance to back off the low speed compression on the external dial. There was still something of a dead ride aboard the Aeris though. Which is strange given Bird does take the time to tune their shocks with SRAM, something that has to be applauded in a small brand. Bird has produced a bike with suspension performance just how they like it, but ultimately it’s a bike that we don’t like the ride feel of.

bird aeris


Frame:6066 aluminium, 145mm travel
Shock:RockShox Deluxe RT3 DebonAir
Fork:RockShox Pike RC DebonAir, 150mm
Wheels:DT Swiss M1900 Spline, Maxxis Minion DHF/Rekon 2.27.5x2.6 tyres
Drivetrain:SRAM GX Eagle 34T chainset, GX Eagle r-mech and shifter
Brakes:SRAM Guide R, 180/160mm
Components:RaceFace Turbine 800mm bar, RaceFace Aeffect 40mm stem, RockShox Reverb Stealth 150mm post, Fabric Scoop saddle
Weight:13.61kg (30.0lb)
Sizes:S, M, ML, L XL
Size tested:L
Head angle:65.7°
Seat angle:74.3°
BB height:344mm
Front centre:826mm
Down tube:742mm
Top tube:655mm