Review: Niner Bikes WFO 9 29er

, Review: Niner Bikes WFO 9 29er

Niner - Sun Valley

Niner WFO 9 – 29er Review

words: Toni W.

Holy crap, 29er’s have invaded Sicklines! And you know what, at risk of spoiling the article, I’m going to tell you right off the bat that I was totally stoked on this ride. The Niner W.F.O. is straight up one of the most fun All-Mountain bikes I’ve ridden. This bike dropped into my review quiver in late spring and has rather dominated my attention ever since. No, I didn’t decide to embrace lycra and yes, I still like pinning DH more than anything. So, what’s the deal with the Niner W.F.O.? The Niner website suggests that W.F.O. stands for Wide, Full Open. I’d venture a guess that it actually means Wide F’n Open. Whatever the true translation, it seems that Niner feels they’ve brought a real contender for the Enduro-All Mountain-Freeride market. So I prodded to have them send one over so I could find out what the big wheeled beast was all about.

Video: A relaxing day on the W.F.O 9

, Review: Niner Bikes WFO 9 29er

Niner W.F.O. driveside scenery

And just how does one go about designing a big wheeled bike to handle the terrain typically reserved for the like of 6″ travel 26’ers? My size small specs a 16″ seat tube and a dropped 23″ top tube for good stand over room, even by my 30″ inseam. At 5’8″ I’m not the stereotypical 29’er customer so I was pleased to see that the small fit me much like any other bike in my stable. The W.F.O. gets 140 mm (5.5″) of travel out of it’s patented CVA suspension via a 7.875″ x 2.25″ shock. I measured the head tube angle right at 68º with a 140 mm FOX 34 and chain stay’s measure up at 17.9″. The angleset compatible tapered head tube uses a 44 mm upper and a 56 mm lower cup and measures 4.7″ in height. Ticking all the boxes of a frame designed to be ridden hard, ISCG-03 tabs, a 12×142 rear axle and heavy duty pivot hardware are all present and accounted for. All of these design elements are attached to oversized hydro-formed tubes that appear quite up to the task of taking a beating. Niner even left plenty of room in the chain stays for the fairly massive 2.35 Hans Dampf or pretty much any other heavy duty 29’er tire that you’d like to run.

, Review: Niner Bikes WFO 9 29er

Decent Tire clearance even with a large tire like the Schwalbe 2.35 Hans Dampf

The Geometry
The geometry on a 29er is not easily translated to a 26″ geometry table so this maybe useful to some and others not as much. Don’t be scared by some of the numbers if you’re used to seeing 26″ geometry. Visit Niner’s website for more details on the geometry and sizing suggestions.

The Build

Taking a look at the custom setup that Niner sent over, they certainly are capable of outfitting a solid custom build.  When I pulled the W.F.O. out of the box I found a big fork, a 1×10 drivetrain, 31″ bars, and 2.35″ tires. This isn’t the typical build they do but certainly shows that Niner knows how to outfit a purpose built bike when asked.

I tweaked the build a little to suit my personal tastes but I kept this one mostly stock. The forward cockpit consists of Race Face Atlas flat bars, a Chromag Ranger 50 mm stem and ESI Chunky grips. Shimano’s XT brakes with 180 mm rotors front and rear and a rear XT shifter round out the bolt-ons up front. For the rear cockpit I alternated between a Reverb with WTB Devo saddle for trail riding and a Chromag Moon mounted to a Thomson Elite post for DH/FR duty. Between the flat bars and zero-rise 50 mm stem It was no problem keeping the front end to a reasonable height even with the tall wheels.

, Review: Niner Bikes WFO 9 29er


Out back our W.F.O. is sporting 142 rear hub spacing and employs a Maxle rear axle. A Monarch Plus RC-3 custom tuned for Niner was spec’d to keep the rear end tracking and will be the only stock shock option going forward. The Monarch Plus has adjustable rebound and a three position lever to dial in compression in addition to the adjustable air spring. Niner shipped a really nice set of Race Face Turbine cranks and a MRP S4 guide which I ran for a few weeks without any issue. I swapped in a set of Race Face SIXC cranks with a 32t Chromag chainring to save a few precious grams but had nothing but solid performance out of the stock bits. An XT Shadow rear derailleur and XX cassette kept thing things shifting flawlessly with minimal mass. I swapped between XTR trail clipless pedals and Twenty 6 Predator flats depending on the ride.

, Review: Niner Bikes WFO 9 29er

Niner W.F.O. chainguide

Fox’s 140 mm 34 chassis is the most compelling fork option for long travel 29’ers these days aside from the Manitou Dorado which I don’t think really suits this chassis. The 34 mm stanchions combined with a tapered steerer provide plenty of stiffness with a little less stiction than you might typically get with a 36 mm stanchion. I tend to be the type that goes for non-travel adjust forks but I wound up using the 120 mm setting a fair amount on the W.F.O. as I racked up several days with big climbing numbers. Sun’s Charger TR wheel set proved to be a serious set of wheels ready to handle a beating. I had a bit of an issue with flex initially but it turned out to be a spoke tension issue. The wheels had already logged some hard miles before I received them and had loosened up a bit. The Charger TR’s were setup tubeless with just a wrap of NoTubes yellow tape and the 2.35 Schwalbe Hans Dampf’s beaded up with a confidence inspiring pop. It was little hassle to swap between a Hans Dampf and a Racing Ralph in the rear depending on what I kind of riding I was up to. The 29″ Dampf provides near DH race levels of grip but is a bit slow and heavy for longer trail rides with lots of climbing where the Racing Ralph is extremely fast rolling and loose in a fun way.

, Review: Niner Bikes WFO 9 29er

Niner W.F.O. profile shot

In the shot below you can get a good view of the CVA linkage design and how it aligns relative to the front chainring. Niner holds a patent for CVA which stands for Constantly Varying Arc. Note that the links are oriented such that chain torque is trying to pull the two links apart. Since the rear triangle is one piece, this is not possible and therefore the chain torque is applied efficiently to turning the rear wheel. Niner claims that this design does not hinge on front chainring size and therefore on bikes equiped with a front derailleur, it pedals efficiently in all chainrings. Since our test bike has only one ring (and we didn’t have it any other way) we can’t speak to test that claim but the reasoning seemed sound. CVA need’s a bit of bottom out control and is well suited to an air damper. I found the tune on the Monarch to be just about the right mixture for aggressive trail riding in the low compression setting.

, Review: Niner Bikes WFO 9 29er

Shock / Pivots

The Ride
OK, time to talk about the ride. Over the past few months, I’ve jumped it, ran it down DH lines, got all sideways, crashed, and of course, rode it on some regular old trail. Basically, I rode it all over the place, you know, like a mountain bike should be ridden. On it’s very first ride I took it down 20 odd miles of Moab’s Porcupine Rim and the W.F.O. was feeling fast and capable on the first climb. I noticed the weight of the wheels and tires when I accelerated out of tight switchbacks, but I noticed the traction even more. I’m thinking a set of carbon wheels would be money well spent here. The first descent started out feeling a bit harsh. A quick stop to throw the compression setting on the Monarch from the high to the low position and drop tire pressure a couple psi and suddenly the story was quite the opposite. The W.F.O. really settled down and started tracking much better. It turns out CVA responds really well with a light compression setting. I found myself carrying unprecedented speed through sections of trail that I know well. More impressive, cornering grip in the loose, sandy turns was very predictable. By the end of my first ride out , I was carrying more speed on almost every part of what is a very challenging trail than any other bike I’ve taken down it to date. To say I was impressed is an understatement.

, Review: Niner Bikes WFO 9 29er

Sun Valley

My typical riding style is fairly lively. I like to pop off every hit, slot into corners, you know, ride for fun. I rode a few 29″ full suspension bikes a few years back that sucked the life out of that kind of riding. I formed a fairly harsh opinion against 29’ers following these early experiences but here it’s rather clear as day that they were just bad examples of big wheeled bikes. I’ll catch some hell in some circles for giving the thumbs up to the wagon wheels but I’d be lying if I didn’t admit to having more fun on the W.F.O. than I’ve had on most trail bikes lately. I’ve found that with a little adjustment in riding style, the poppy, playful, slidey kind of riding that I love is not only possible, but down right awesome on board the big wheeled machine. Most things, like rolling back into a manual or backing into a turn are just as you might expect, a little different, but hardly impossible. During the course of this review, my other trail bikes wound up collecting dust while the WFO became my go-to ride when I wanted to get sideways on rowdy trails.

, Review: Niner Bikes WFO 9 29er

Tossing the W.F.O. 29er

With the W.F.O. so handily dispatching with so called aggressive trails with relative ease, I decided to crank things up a notch. I mean, Wide F’n Open means one ought to really be able to get after things on this rig, right? So I cruised up to one of my favorite steep DH lines. Turns out, it was in full mid-summer form, complete with a nice layer moon dust that tests the best riders and their rigs. Once again, the big wheels hooked up where there was no traction and held impossible off camber lines, roots and loose rock be damned. The footprint of the big tires allowed the Hans Dampfs to hook up at levels usually reserved for DH race tires. In the steeps, the sensation of the 68º head tube angle combined with the big wheels is quite a bit different than a 26 in a couple ways. For one, you never get that visual of the front axle way out ahead of you even though the front end feels extremely stable through the bars. With my brain conditioned to seeing things in 26’er context this took a little getting used to. Things are further complicated in that the big wheels are willing to roll smoothly over much larger obstacles than you’d expect out of a bike with this little travel. But then again, at a certain point, there’s no hiding the fact that we’re working with only 140 mm of travel. I found that I had to play by new rules and interpret the feedback from the trail in a different way. It’s quite a task to try to translate the 26″ paradigm to 29″ when it comes to these discussions. There are so many data points that are much different than any 26″ bike that I’ve ridden that it would be pointless to try and draw a simple parallel between them. Rather, I’ll let the W.F.O. stand on its own merits as the fastest All Mountain bike that I’ve had the pleasure of riding down a proper DH line.

, Review: Niner Bikes WFO 9 29er

W.F.O. descending a technical section of trail

I have to admit that going into this, I had an uneasy feeling about getting the big wheels airborne for more than a second. I was ready to try, but after so many years of riding 26er’s, let’s just say I had some reservations. I suppose I spent a fair amount of time wondering what they’d feel like trying to toss them around, if they’d buck or shoot me off in weird directions. The unknown can be so daunting sometimes. Ultimately jumping the W.F.O. feels a whole lot like jumping any other bike of its approximate wheelbase. It’s stable, composed, and there’s nothing all that weird going on. You can certainly feel those big wheels spinning in the air, but fortunately they contribute to the bike wanting to fly straight and true. Still, it doesn’t take noticeably more effort to whip the W.F.O. sideways than your typical DH bike. In fact, flying the big 29’er felt totally natural back to back with my DH rig. I wound up getting in quite a few bike park days switching back and forth between this and my Pivot Phoenix and was stoked on how easy it was to move between the two bikes.

, Review: Niner Bikes WFO 9 29er

Niner - Trail Boss

The more I rode the W.F.O. the more it started to feel like it was up for almost anything. I mean, I’m sure the big wheels are a pain in the ass to flip or 360 on, but that’s not really my area of expertise any way. Anything from a 5000′ climb to a steep DH line to a road gap is well within reach; you know “ALL mountain”. I’d imagine the W.F.O. would be a real weapon in the Enduro race scene. If you spend a lot of time hucking you might need to tweak the suspension an bit to handle the hardest hits. I certainly found the limits of the 34 Talas but a Float would have likely handled the harsher landings a bit better as it is easier to fine tune how the fork progresses into its travel. The Monarch RC-3 is outstanding as a heavy duty trail shock but I did eventually have trouble finding the balance between traction and bottom-out resistance.

But, keeping this all in context, I’m talking about little tweaks to get a 140 mm, 31 lb trail bike down legit DH lines and the roughest Enduro terrain at full speed. It’s just really hard to keep this in mind once the bike is in your hands.

, Review: Niner Bikes WFO 9 29er

Niner WFO (click to see spec details)

There are few trail bikes that I’d want to climb thousands of vertical and feel comfortable shredding back DH. The speed, stability, and traction of the W.F.O. had me feeling rather invincible and honestly, the bike handled every crazy line I had the balls to try without complaint.


  • $1900.00 Frame Only
  • Additional complete build options also available
, Review: Niner Bikes WFO 9 29er

29ers are not supposed to do that right...

, Review: Niner Bikes WFO 9 29erIf you’re looking to purchase an Niner for yourself we suggest checking out a reputable dealer like Fanatik Bike in Bellingham, WA. They are an experienced dealer with great customer service and attention to detail.

Well, I already spoiled the ending so there’s not much news here. I really like the W.F.O. It suits my style and it’s going to be a bummer to have to give it back. I’m addicted to the speed it carries and have adapted to the big wheel idiosyncrasies. Cornering is truly on another level and traction in our sandy soil makes me grin ear to ear. Cornering line choice has to be taken a little wider with the bigger wheels compared to a 26er but once you get acquainted with the technique it is no problem. I can feel the extra heft in the bigger wheels accelerating out of tight switchbacks but over the course of a long ride, the other benefits seem to only make me faster. Biking is all about personal experience and if it was possible that you might enjoy the trail better with a 29er why wouldn’t you try one? Perhaps a far more relevant measure is the fun factor and for me, the W.F.O. rates with the best of them. While I’m hardly ready to cast aside the best of the 26″ bikes out there, I’d place the W.F.O. among them as one of the best All-Mountain rigs on the market to date.

The Good

  • Very fast through rolling terrain, over roots, and downhill terrain
  • Gobs of cornering traction
  • Responsive pedaling performance
  • Pivots and linkage hardware stayed tight and quiet
  • AngleSet compatible should you choose to alter the head angle

Worth Considering

  • At 13.75″, I felt the bottom bracket could be a hair lower
  • Shock hardware at 6mm is a bit under sized and is susceptible to being bent on a gravity bike
  • A shorter head tube on the small would allow for more flexibility in bar setup
  • ISCG-03 tabs are welded on and it would be nice to have a full bead around it or CNC’d into the shell for additional strength.
  • The bigger 29er wheels have more wheel flex and weigh more in general. This could result in a fairly costly carbon wheel purchase.