Bird's 5-star all-mountain hardtail gets reworked for 2018

Bird treats the Zero AM to a new back-end and gives it the longer/slacker treatment

Not many bikes get a full coveted 5-star review from the BikeRadar test team, but Bird managed that with its Zero AM2 hardtail last year. Not one to rest on its laurels though, it's back with a revised Zero AM Boost.

It probably won't take a genius to work out at least one of the revisions on the new bike — you just need to look at the model's name. Yep, Bird's aggressive, long travel hardtail now comes with a boost-width back end.

How much this really matters, in terms of wheel stiffness and ride quality, is up for debate, however with the industry pushing it as a whole it makes sense for Bird to make this revision. At the very least, it makes speccing and/or upgrading the bike with the latest wheel products a whole lot easier in the future. 

We've already found that having a boost fork and non-boost frame makes it a bit of a pain getting new hoops with Tom's long-term Transition Scout, and most modern forks are going boost width these days.

The frame is longer and slacker, with the all-important boost back end
The frame is longer and slacker, with the all-important boost back end

So what else is new with the Zero AM?

It's not difficult to guess this either, it's where most bikes are going anyway — longer and slacker. 

The front end reach has increased by an impressive 23mm in size large (453mm up to 476mm) to bring it in line with Bird's progressively shaped Aeris 145 and AM9 enduro bikes.

The head angle has slackened to 64.5 degrees, from 65.4 on the previous generation bike, with an un-sagged 150mm fork, while the seat angle remains at 74 degrees.

While the original bike was designed for 150mm forks, the AM Boost will now also come with a 160mm option, pushing the head angle out to an even slacker 64.1 degrees.

External cable routing and a threaded BB are a mechanic's best friend
External cable routing and a threaded BB are a mechanic's best friend

What else do you need to know?

The AM Boost still has short chainstays; 420mm in the Medium and Medium Long, while the Large and XL come with 425mm stays, which gives better fore-aft geometry balance with the longer front end.

You can plug 27.5 x 2.8" rubber in the back, and there's ISCG05 chainguide mounts present. External cable routing and standard threaded 73mm bottom bracket shells will make your mechanic happy too.

Neat detailing on the chainstay yoke
Neat detailing on the chainstay yoke

Buying a Bird

One of the things we've always liked about Bird is its sales model. You buy direct from Bird, which helps keep prices incredibly competitive, but you also get the opportunity to swap components around at the point of purchase. Got a bit extra cash but want to upgrade from Yari to Lyrik? No worries. Don't like the Maxxis Minion? Sling a Shorty on instead.

Bird's Zero AM Boost bikes will start from £1,374 with a RockShox Revelation RC fork, DT Swiss M1900 wheels, SRAM NX11 gears, Level T brakes, RaceFace and Fabric finishing kit, and tubeless out-of-the-box Maxxis tyres.

Bird's Zero AM Boost is the next natural step in the Zero AM family
Bird's Zero AM Boost is the next natural step in the Zero AM family

Not one to have shy colourways, the frames will be available in blue/orange, yellow/pink or stealth black.

Shipping will start internationally in mid-December, but you can order one... Now!

Tom Marvin

Technical Editor, Tech Hub, UK
Tom's been riding for 15 years, and has always chopped and changed bikes as soon as his budget allowed. He's most at home in the big mountains, having spent nigh on 30 weeks riding the Alps, as well as having lived a stone's throw from the Scottish Highlands for four years. Tom also enjoys racing events like the Strathpuffer and the Trans Nepal.
  • Discipline: Mountain
  • Preferred Terrain: Steep and super tech or fast and flowy
  • Current Bikes: Canyon Spectral, Pivot Mach 429SL, Mondraker Vantage R +
  • Dream Bike: Transition Scout
  • Beer of Choice: Gin & tonic
  • Location: Bristol, UK

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