Niner Air 9 Carbon frame review

State-of-the-art flyweight 29er

Our rating 
4.5 out of 5 star rating 4.5
GBP £1,699.00 RRP | USD $1,899.00

Our review

This is one of our favourite bikes right now – if you want to cover ground quickly, get an Air 9 Carbon
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There aren’t many 29er-only manufacturers out there but Niner are a big part of the vanguard, promoting big wheels with almost evangelical zeal. The Air 9 Carbon is their flagship hardtail, incorporating the geometry that the company have been refining since they started but rendered in ultra light carbon fibre.


Ride & handling: Light, stiff and comfy all at once, and spectacularly fast at all times

In common with many 29ers, Niner’s sizing isn’t quite what you’d expect if you’re used to 26in wheels. Our test model was a medium but had a top tube length that you might expect from a large and a seat tube that would be at home on a small. But with a 400mm seatpost it was a good fit for 6ft tall testers, with height to spare. The cockpit setup was well thought out, with a flat but wide bar keeping the grips below the seat and delivering suitable weight distribution.

As 29ers go, the Niner is fairly low and steep at the front, and short at the back. Combined with its light weight, this gives the Air 9 Carbon a real edge out on the trail. This is a blisteringly and addictively fast bike. Pedal and it goes – instant gratification on two wheels. Cornering responses are equally lively, to the extent that the bike can feel a little bit nervous at speed.

But have confidence and take control and it will see you through – the big wheels and sure-tracking chassis will work in your favour. As well as being fast in every sense, the Niner somehow manages to be comfortable too. Looking at the huge tubes and fat seatpost you might expect it to be bumpier but a combination of big tyres and clever carbon layup makes it a fine place to be on long rides.

The Air 9 Carbon is race light but trail capable, stiff and comfy at the same time. It’s also fast as you like and one of the best-looking bikes made by anyone, anywhere, ever. Yes, it costs all the money in the world but it’s properly ace. We’re off to look for things to sell…

Frame: State-of-the-art chassis with amazing looks; big tubes amplify clonks and bangs

Niner managed to cause quite a stir when they debuted the Air 9 Carbon at the trade shows a couple of years back. And trying it out now it’s not hard to see why. First up, this is a fine-looking mountain bike – we’ve found that even people who go out of their way to dislike 29ers tend to like the look of it. From the tapered head tube to the carbon post mount back end it’s a state-of-the-art frame.

It’s also extremely low-slung but packs huge tubes. There’s not much point mounting a Crud Catcher to the Niner’s hexagonal down tube, for example, since the tube itself is as much mudguard as you’ll be likely to need this winter. Despite the girthsome tubes, the frame comes in at well under 3lb – pretty good for a big-wheeler. The tube merges seamlessly into the bottom bracket, where you’ll find Niner’s CYA bottom bracket system.

This essentially involves having a bigger hole in the frame than any bottom bracket/crank setup needs and then using adaptor cups to step it down to the required size. You can fit pretty much any kind of crank in there with the right cups. Or the CYA system will accept Niner’s own eccentric bottom bracket system so you can tension the chain on a singlespeed setup. If you’re doing that you can also swap the drive side dropout insert for one without a derailleur hanger for a clean look.

Niner clearly realise that scraping your new, extremely expensive carbon frame would be a painful experience. So the Air 9 Carbon comes with a hefty strip of helicopter tape along the underside of the down tube, plus titanium plates by the bottom bracket and on the chainstay to ward off damage from a dropped or sucked chain. Gear cables are routed internally, with the housings entering via holes in the head badge, which is a rather neat touch.

In common with most high-end models, the Air 9 Carbon is supplied as a bare frame – all you need to do is add parts to taste. It’s designed for an 80 or 100mm travel (3.1 or 3.9in) suspension fork or Niner’s own super-light carbon rigid fork. Our test bike arrived with a 100mm Fox F29 RLC up front, with a QR15 axle to add extra steering authority.

We were pleased to see a flat Syntace bar up front, compensating for the inevitably high front end that a 29in wheel and 100mm of fork travel dictate. Transmission and brakes were all from SRAM’s new X0 group and worked without complaint, though the acoustic properties of the carbon frame made the shifts seem clankier than we’re used to. SRAM’s always a bit clickier than Shimano anyway, but once the sound has echoed around the big hollow frame it sounds louder.

Niner air 9 carbon frame: niner air 9 carbon frame
Steve Behr

This article was originally published in Mountain Biking UK magazine.

Product Specifications


Name AIR 9 frame (11)
Brand Niner

Available Colours Vana White
Saddle Fi'zi:k Aliante XM
Top Tube (in) 23.75
Standover Height (in) 28.6
Seat Tube (in) 16.5
Chainstays (in) 17.3
Spoke Type Stainless
Weight (lb) 22.6
Weight (kg) 10.24
Stem Bontrager XXX, 80mm
Shifters X0 triggers
Seatpost Elite
Seat Angle 73
Rims Stan's ZTR Crest 29er
Available Sizes L M XL M L S S M L S M L XL S M L XL S M S M L M L XL M L XL S S
Rear Derailleur XO
Headset Type FSA tapered semi-integrated
Head Angle 72
Handlebar EC70
Front Derailleur XO
Frame Material 40T high modulus carbon-fibre
Fork Fox F29 RLC 100mm (3.9in)
Cranks Truvativ X0 26-39
Chain PC 1071
Cassette SRAM PG 1070 11-36 10-spd
Brakes Shimano M445
Bottom Bracket Truvativ BB30
Wheelbase (in) 42.7