Following Bird’s first foray into big-wheeled bikes with its Aeris AM9 full-susser, it's turned its attention to wagon-wheeling the Zero hardtail.
Based on the 650b-wheeled Zero TR, with its long/low/slack geometry, the 29er version promises to keep things rowdy, fun and very fast.
But like a responsible older brother, it’ll help keep you out of trouble when you get out of your depth.
Bird Zero 29 frame
The Zero 29 is a formidable beast: a 6061-T6 aluminium monster, with a geometry sheet that made me look twice. It has a staggering 80mm of bottom bracket drop, combined with a 64-degree head angle, 74-degree seat angle and 1,194mm wheelbase (based on the ML frame, which just about fitted my 6-foot height). All of this adds up to create an aggressive bike that loves to be pushed hard.
While the long/low/slack trend is definitely present and correct here, the designers at Bird have opted to keep the chainstays relatively short (435mm on the ML).
The ride feels nicely balanced though, and this ensures that the bike is a whole lot of fun and, importantly, doesn’t handle like a barge when you’re throwing it around tight turns.
Bird Zero 29 kit
My test bike was assembled by the guys at Bird and sent over as is, but you’d normally have the choice to customise your Zero 29 from a pretty generous selection of components.
The SRAM GX Eagle drivetrain and Descendant cranks, 130mm-travel RockShox Revelation fork and Shimano Deore brakes constitute a pretty sturdy set-up.
A pleasant surprise was the addition of Bird’s own dropper post — a cable-operated unit that kept working well with no significant play or issues with cable tension or stretch.
The wheels combined DT Swiss XM 481 rims with Hope Pro 4 hubs, and caused me no issues, while the Maxxis Minion DHF/Aggressor tyre pairing was ideal for the trails I rode.
Bird Zero 29 ride impressions
An aluminium frame as compact as this is never going to be super-comfortable or the best choice for all-day epics. In fact, it’s pretty stiff and unforgiving.
Fortunately, this is something that you’ll probably only notice once you’ve stopped grinning like an idiot at the bottom of the trail, and noticed that your hands and arms are a bit sore. It really feels like this is as close to a pure-fun bike as a big-wheeler will ever get.
The short-travel fork belies the Zero 29’s rowdy nature, and you’ll soon notice that the Strava times you’re notching up aren’t hugely different to those you get on your full-suspension enduro rig — you might just ache a bit more the next day.
It fires around corners with effortless ease, like a jump bike on a pump track, and hops and manuals through technical and rooty sections with great confidence for a bike of its size.
Those 29in wheels allow you to carry decent speed on flatter trails too, and they play an important role in smoothing out rougher, more technical sections. Much like its smaller-wheeled brother, riding the Zero 29er made me question whether you even need a rear shock.
Bird Zero 29 specifications
- Sizes (*tested): M, ML*, L, XL
- Weight: 12.82kg (28.26lb), ML size without pedals
- Frame: 6061-T6 aluminium
- Fork: RockShox Revelation RC, 130mm (5.1in) travel
- Shifters: SRAM GX Eagle
- Derailleurs: SRAM GX Eagle
- Cranks: SRAM Descendant cranks (1x12)
- Wheelset: DT Swiss XM 481 rims on Hope Pro 4 hubs
- Tyres: Maxxis Minion DHF 3C EXO TR (f) and Maxxis Aggressor EXO TR (r) 29x2.3in
- Brakes: Shimano Deore M6000
- Bar: Race Face Æffect R, 780mm
- Stem: Race Face Turbine R, 40mm
- Seatpost: Bird Down 150mm dropper
- Saddle: Fabric Scoop
Bird Zero 29 geometry
- Head angle: 64.3 degrees
- Seat angle: 74 degrees
- Chainstay: 43.5cm / 17.13in
- Seat tube: 44cm / 17.32in
- Top tube: 63cm / 24.8in
- Head tube: 12cm / 4.72in
- Bottom bracket drop: 8cm / 3.15in
- Wheelbase: 1,194mm / 47.01in
- Stack: 66.1cm / 26.02in
- Reach: 46cm / 18.11in
- Price: £2,103 (custom) / buy direct from site