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2021 Niner WFO 9 RDO 4-Star XT 12-Speed Bike

Vital Rating: (Excellent)
2021 Niner WFO 9 RDO 4-Star XT - Silver/Black
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Product Review - 2021 Niner WFO 9 RDO

We put the all-new big mountain bike from Niner to the test with two riders in three states.

Rating: Vital Review
Product Review - 2021 Niner WFO 9 RDO

Niner's WFO name has been notably absent from the line and riders have been asking for its return. Happy to oblige, Niner has revived the WFO in the form of a 170mm travel 29er built upon its current RDO carbon frame. Everything mountain bikers have come to expect from long-travel bikes is present - a 180mm FOX 38 fork, FOX X2 rear shock, 200mm rotors, and meaty tires are mounted on all five builds. Vital had two testers give the new Niner WFO a go. Let's get into our initial impressions.


  • Excellent climber
  • Mows down any obstacle
  • Eats up square-edge hits
  • No harsh bottom-out


  • 2.6-inch Tire spec is not for everyone
  • Takes muscle to move and corner


  • RDO Carbon frame
  • 29-inch wheels
  • 170mm (6.7-inches) of rear wheel travel // 180mm (7-inches) fork travel
  • CVA suspension design
  • Guided internal cable routing
  • Flip Chip - .7-degree change in head angle
  • Enduro Max Black Oxide bearings
  • Lifetime frame warranty
  • 73mm threaded bottom bracket with ISCG 05 mounts
  • Boost 148 rear spacing with 12mm through axle
  • SRAM UDH derailleur hanger
  • Measured weight (size medium, Shimano XT pedals): 33.42 pounds (15.16kg)
  • MSRP $6,950 USD (as tested)

The new WFO uses Niner's CVA suspension design to obtain 170mm of rear travel. All frames in the line are Niner's RDO carbon fiber. The WFO has a flip chip in the upper rocker arm to adjust the geometry +/- .7-degrees in the head and seat angle. Much the same as other models, the flip chip does use a host of small parts, so we would recommend the swap be done in the shop. Internal cable routing, the standard rubber frame protection (chainstay, bottom bracket, shuttle zone) and a thick coat of paint finish off the details.

Niner WFO Flip Chip


The new WFO comes in just three sizes - small, medium, and large. Riders in the "X" category are out of luck on this one. Niner ships the WFO in the low setting, giving riders a 64-degree head angle and 77-degree seat angle. Reach on our medium test bike is 450mm. Size large comes in at 480mm. Putting the bike in the high position not only steepens the head and seat tube angles, it also extends the reach by 7mm. Regardless of size, the chainstay length on the WFO is 433mm.




Taking in the Niner WFO takes a minute. There is a lot going on here. Anyone that has seen a Niner before will be familiar with the lines and linkages of the Colorado brand's CVA suspension design. Dig deeper and riders will begin to notice a shuttle guard, bottom bracket and robust chainstay protection. The linkage below the bottom bracket has a bolt-on skid plate as well. Just above the bottom bracket, on the seat tube, are plastic guides to keep the derailleur and rear brake lines in check. Sprinkle on mounts for your water bottle (inside the front triangle) and the setup is complete.


With all the extra action happening throughout the frame, Niner has done well in creating subtle, smooth cable ports at the head tube and exit points. The overall finish quality of the Niner WFO is very nice. The attention to detail is evident.


Starting with suspension, our FOX 38 came with one volume reducer installed, so that is what we ran. The FOX forks have been plenty progressive on their own lately, so we didn't feel the need to cram additional spacers in there. For phase one of the test, our rider put in the suggest pressure (87psi). When Griz took the reigns, he took the pressure up to 103psi. For both riders, the 38 was exceptionally smooth off the top with plenty of support.

Each rider took different approaches to tuning, but ultimately, it was Griz that cracked the code with compression and rebound settings. For the FOX 38, we settled on one click of high-speed compression and eight clicks of low-speed compression. For rebound, we ran five clicks of low-speed and two clicks of high-speed rebound. All counts were from the fully open position.


In setting up the FOX X2 Factory, again, each rider went for 30% sag (180psi for Brad, 195psi for Griz). Ultimately, the X2 was run wide open on the compression settings with seven clicks of low-speed rebound and six clicks of high-speed rebound.

As most bikes do now, our WFO came with 800mm wide bars, perfect for cutting down to riders' preferred size.

Set up for proper leg extension when pedaling, the 150mm KS LEV-Si on our medium test bike gave ample room when compressed for the descents. We found this somewhat notable because we've become accustomed to a 170mm or greater dropper, leaving a 150mm on some bikes feeling too tall. This was not the case for us on the Niner WFO.


On The Trail

Vital used two different testers and drug the Niner WFO around the foothills and moto trails of Boise, ID, the red rocks of Reno, NV and the steeps of Pine Valley, CA. We wanted to make sure a big bike like the WFO got a fare shake.

Early rides on the WFO surprised us. With an expectation of an uphill slog, we found the Niner WFO to scoot up the hill with ease. Regardless of scales, the perceived weight of this bike felt downright svelte. The riding position and geometry were very comfortable from the onset. Getting into the real meat of the climbs, the Niner WFO was sure-footed and ratcheted us up even the steepest grades much like a roller coaster, only faster. It's like the top tube says, "pedal, damn it."

Serious stoppers
No wandering from this set

Technical bits were easily overcome with a quick shot of power, while the monster truck nature did the rest. For fire road ascents, we did make use of the FOX X2 climb switch. The WFO doesn't bob excessively, nor did we feel like we were being sapped of precious energy during longer slogs, but if the switch is there, use it. In all, we really liked how the WFO climbed. Not just for a large, enduro bike, but for any mountain bike.

When the climb is done, the fun begins. Any rider reaching for a 170mm 29er isn't likely to have "playing" on their mind. To that end, the WFO does an ok job at staying lively on the trail, though that isn't really its reason for being. WFO stands for "Wide Full Open," and that is exactly where this bike is happiest. If rolling terrain, a little chunk and trailside jumps are your ride du jour, then the WFO has no patience for you or your low expectations. With a nature to get riders to the far-away, raw trails, the Niner WFO wants you to smash everything in sight.


High-frequency chatter (SoCal rock gardens) felt great after making some adjustments to the rear shock (softening low-speed compression and speeding up low speed rebound). When running too much compression and rebound, the rear end would “pack up” and gave a stinkbug feedback – pushing the rider's center of gravity toward the front end where the just-slack-enough head angle did not feel as slack to compensate. Square edge performance was amazing, even with the slow and stiff shock setting we started off with. We would almost say the WFO has a high single pivot sensation to it with how well it handles square edges. Bump jumps and jibs are an area where the WFO felt dull and lacked pop – likely due to the falling rate towards the bottom 33% of suspension travel. The WFO feels like more of a stable plower than a poppy prancer.

While we would put the WFO in the plow bike category, we would not call it a pig or one-trick pony. It does not get held up in flatter portions of trail and really held its own against much smaller bikes. Conversely, while those smaller bikes are fun on rolling terrain, riders may be able to do some light reading or catch a snooze aboard the WFO.


We appreciated the WFO's ability to gobble up square-edged hits, regardless of speed or pitch. A particular strength came out on high-speed, steep sections of trail. Our Niner stayed calm and planted, allowing us to dig and and make line choices when other bikes may have you feeling like a passenger. Ultimately, this is a big bike, riders will have to treat it as such.

Build Kit

5-Star X01 AXS - $10,100
5-Star X01 - $8,300
3-Star GX - $6,000
2-Star SX - $4,800

View the full 2021 Niner WFO line and detailed specs in our Product Guide.

Niner uses its star rating system for the build kits. Jumping off with the 2-star kit, riders get FOX Performance suspension and a SRAM SX Eagle drivetrain for $4,800. The 3-star kit sees the jump to FOX Factory suspension and a GX Eagle drivetrain for $6,000. Our test bike is the 4-star kit. Moving up, there are two 5-star builds, the X01 at $8,300 and the top-shelf X01 AXS build for 10,100. All of the WFO line have the same RDO Carbon frame.

Fork Performance

If a bike brand is going to use FOX suspension, can they all be 38's? We've ridden this massive fork on a number of bikes and it's always the same - butter smooth and supple off the top with a bounty of tuning to suit all types of riders.

Tire Performance

Schwalbe's Magic Mary and Hans Dampf tires are well regarded in the traction domain. In the dry, early spring conditions, the 2.6-inch meats proved less than ideal. When the trail is damp or when totally blown (as in, late summer) they do deliver confident cornering. When navigating loose-over-hard-pack, they were drifty and vague at best. Running them with scary-low pressure up front did help but the setup was less than ideal. Flat corners brought out weakness in the tire combination where the front end would push more than desired while the rear end tracked. Fortunately, we did get these meats into some softer conditions to really let them and the WFO shine. We understand you have to run the rubber that suites your environment, so this is not an objective knock on Schwalbe, but desert rats beware.

29x2.6-inch Magic Mary Front
29x2.6-inch Hans Dampf Rear

Wheel Performance

Due to supply chain shortages, our test bike came with Industry Nine hoops instead of the standard spec'd DT Swiss EX1700. For our part, we enjoyed the Industry Nine wheels.

Dropper Post

Though the KS LEV-Si may not be the most flashy of posts, it did its job well enough. Actuation is smooth and consistant. Our only grip would be that when picking up the bike by the saddle, the post will extend. The KS will immediately compress when let go and really, this is a bad habit anyway, but we have to take our gripes where we can.



The Niner WFO is the sort of fearless charger that will allow you to pass your friends on wide-open sections of trail. These passes will be well telegraphed though. Our WFO had quite a few rattles in rock gardens. The noise sounded like reverberations through the frame and were a challenge to attribute to any one thing.

Long Term Durability

We lost the skid plate on our lower linkage pretty quickly in testing. Evidently it is held on with two small screws. In all, there are a lot of bolts and pivots to look after with Niner's CVT design. While we performed a standard pivot check on our WFO out of the box, we missed the little fellas on the skid plate.

Skid Plate still attached

There are a lot of pivots which seem intimidating to service out of a home garage. As long as your local Niner dealer could handle this job, rider's should be fine. Pivot service seems like a job outside the realm of most home mechanics.

Niner's finish quality and paint are up there with the best and the rubber protection on the frame is plenty sufficient. If riders do their due-diligence with the bolts, the WFO should hold up well over the years.


What's The Bottom Line?

Niner makes no bones about the WFO. The ride quality is literally in the name - wide full open. While this Niner does decent at playing well in a variety of settings, this is a bike best suited for big terrain and high speeds, as any long-travel 29er should be. We were floored with the WFO's climbing manners and had an absolute gas unloading both barrels on the downhills. Riders that explore big terrain and want to level the nastiest trail will have a friend in the WFO.

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About the Testers

Sean McClendon - Age: 35 // Years Riding: 21 // Height: 5'10" (1.78m) // Weight: 190-pounds (86.2kg)

"Griz" is a battered veteran of MTB gravity racing. Following a major crash during the 2010 USA National Championship Pro downhill race, he put in the hours and fought his way back to health and the fun that is two wheels. Griz has ridden for a number of the USA's top teams throughout his racing career, testing prototype frames and components along the way. Currently managing US Dealer sales and the Fresh Blood amateur development team at DEITY Components, he remains motivated by the mantra "whips don't lie." You'll often find him perfecting his high-flying sideways aerial maneuvers while living the #pinelife in Idaho.

Brad Howell- Age: 41 // Years Riding: 26 // Height: 5'9" (1.75m) // Weight: 165-pounds (74.8kg)

Brad started mountain biking when a 2.25-inch tire was large, and despite having threads, bottom brackets sucked. Riding in the woods with friends eventually lead way to racing, trying to send it at the local gravel pits, and working in bike shops as a wrench to fix those bikes. Fortunate enough to have dug at six Rampages and become friends with some of the sport’s biggest talents, Brad has a broad perspective of what bikes can do and what it means to be a good rider. The past few years Brad worked in the bike industry and got to see the man behind the curtain. These days, though, he just likes riding his bike in the woods with friends.


Product Niner WFO 9 RDO 4-Star XT 12-Speed Bike
Model Year 2021
Riding Type Enduro / All-Mountain, Freeride / Bike Park
Rider Unisex
Sizes and Geometry
S (High, Low), M (High, Low), L (High, Low) View Geometry
Size S (High, Low) M (High, Low) L (High, Low)
Top Tube Length 573, 575 595, 597 625, 627
Head Tube Angle 64.7°, 64.0° 64.7°, 64.0° 64.7°, 64.0°
Head Tube Length 90 95 100
Seat Tube Angle 77.7°, 77.0° 77.7°, 77.0° 77.7°, 77.0°
Seat Tube Length 390 419 462
Bottom Bracket Height 19, 28 drop 19, 28 drop 19, 28 drop
Chainstay Length 435, 438 435, 438 435, 438
Wheelbase 1203, 1205 1225, 1227 1257, 1259
Standover 732, 725 734, 727 755, 748
Reach 437, 430 457, 450 487, 480
Stack 621.6, 624.8 626.6, 629.9 629.9, 635.0
* Additional Info Multiple values for 'High' and 'Low' adjustable geometry positions via flip-chip seatstay pivots
Measurements are in mm unless otherwise noted
Wheel Size 29"
Frame Material Carbon Fiber
Frame Material Details RDO (Race Day Optimized) carbon fiber
Rear Travel 170mm
Rear Shock FOX FLOAT X2 Factory EVOL, HSC/LSC/HSR/LSR, 2-position, Kashima coat, 205x65mm trunnion
Fork FOX 38 FLOAT Factory GRIP2 EVOL, HSC/LSC/HSR/LSR, Kashima Coat, 110x15mm, 44mm offset
Fork Travel 180mm
Head Tube Diameter Tapered
Headset ZS44/28.6 | ZS56/40
Handlebar Race Face Next R, 800mm wide, 35mm rise, 35mm clamp
Stem Race Face Turbine R, 40mm, 35mm clamp
Grips Niner Grrrips, flanged, lock-on
Brakes Shimano XT M8120, metal pad with fin, 203/203mm MT800 rotors
Brake Levers Shimano XT M8100
Drivetrain 1x
Shifters Shimano XT M8100 12-speed I-SPEC EV
Front Derailleur N/A
Rear Derailleur Shimano XT M8100 SGS 12-speed
Chainguide None
Cranks Race Face Next R Carbon 12-speed, 170mm
Chainrings 32 tooth
Bottom Bracket Race Face, 73mm BSA threaded
Pedals None
Chain Shimano XT M8100 with Quick-Link
Cassette Shimano XT M8100, 10-51 tooth, 12-speed
Rims DT Swiss EX 1700 SPLINE wheelset, 30mm
Hubs DT Swiss EX 1700 SPLINE wheelset, centerlock, 110x15mm front, 148 x 12mm rear
Spokes DT Swiss EX 1700 SPLINE wheelset
Tires Front: Schwalbe Magic Mary EVO Super Trail 29"x2.6"
Rear: Schwalbe Hans Dampf EVO Super Trail 29"x2.6"
Saddle Niner Custom TR with Crn-Ti rails, printed Niner graphic
Seatpost KS LEV Si, 125mm (S), 150mm (M), 175mm (L/XL)
Seatpost Diameter 30.9mm
Seatpost Clamp 34.9mm standard single-bolt
Rear Dropout / Hub Dimensions 12mm x 148mm
Max. Tire Size 29"x2.6"
Bottle Cage Mounts Yes
Colors Magnetic Grey/Black, Red
Warranty Lifetime
Weight N/A
  • Adjustable geometry via flip-chips in the seatstay pivots to raise the bottom bracket
  • Constantly Varying Arc (CVA) suspension system
  • Trunnion mount shock adds width and stiffness to the frame and linkage
  • Subtle refinements to the kinematics give it superior pedaling behavior despite 170mm of travel
  • Sensitive in the early stroke and supportive in the mid stroke
  • Slightly falling rate at end stroke for bottomless descending
  • Forged rocker link with crossmember for stiffness
  • Rib Cage struts buttress the bottom bracket area for added stiffness
  • Compact, 1-piece rear triangle with cross-brace for increased stiffness
  • Extra wide seat tube rocker link pivot with double-width bearings for torsional rigidity
  • Short, straight seat tube accommodates 170mm dropper posts
  • Lower link under the bottom bracket allows for short chainstays
  • Sag indicator on the rocker link pivot
  • Enduro max black oxide pivot bearings
  • Oversized lower shock pocket for compatibility with all aftermarket rear shocks
  • Durable frame protection in key locations, including a downtube shuttle guard
  • Smooth, straight full-sleeve internal cable routing
  • SRAM UDH derailleur hanger
  • Price $6,950
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