Over the past few months of riding Otso’s titanium version of their previously-released stainless steel Fenrir, I’ve strayed further into the morass of bike categorization than I ever thought I would, along the way asking myself such snake-eating-its-tail questions as: What is a gravel bike, what is a mountain bike, do modern ATBs even exist?

In a move telling of the bike’s advertised versatility, Otso’s website gives the Fenrir a home under both their Gravel and Mountain categories. The Minnesota-based brand’s own descriptions of it include: “a ride anywhere bike,” “with drop bars, the Fenrir rides like an extra-capable gravel bike,” “not your typical mountain bike,” “designed from the trail up for bikepacking,” and “rides like a 90s XC bike.” In his review of the inaugural stainless model, John Watson dubs the Fenrir a drop bar 29er.

As such, I wanted to give it a chance to shine across the wide-ranging two-wheeled scenarios that abound once you leave the pavement. I’ve ridden the Fenrir in multiple configurations that I’ll detail below and have logged around 700 miles on the Taiwan-made chassis. From the high mountain passes surrounding Crested Butte on a late summer’s tour, to the leafy carpet of New England at the 2022 Nutmeg Nor’easter, and, most recently, on a romp around the Monumental Loop of southern New Mexico, I’ve tested the Fenrir across varied geography and dynamic terrain. My time in the saddle brought me to a couple of realizations: 1) frame design categories are merely a jumping off point to understanding a bike in totality; and 2) for me to most appreciate the Fenrir, I wanted to hone in on an area of specialization among the wide-ranging options offered by this frame.

About the Bike

The Fenrir is a thoughtfully diverse platform that seeks to provide the rider the freedom to roam, wherever and however they choose. Just like its stainless sibling, the 2022-released titanium Fenrir can be set up with drop bars or flat bars. However, the top tube length is long by gravel bike standards and short for a MTB, so Otso’s recommended stem lengths run counter to popular current practice (i.e. longer stems on snappier-sized gravel bikes, shorter stems on longer/slacker MTBs). The frame is suspension corrected and dropper-post compatible.

Otso employs the patented Tuning Chip technology at the rear drop out for chainstay length adjustability and easy singlespeed conversion, and (depending on the chip position) the frame can clear 29” x 2.6” or 27.5” x 2.8” rubber. It almost goes without saying that there are braze-ons galore, as any brand that’s got one eye on the adventure cycling scene should be doing these days anyway.

The titanium update shaves nearly two pounds off the frame weight of the stainless Fenrir (for size L the stainless clocks in at 5.7lbs and the ti at 3.9lbs). While I can’t personally speak to the ride quality of stainless, John provides an overview of this runner-up material in the echelon of fine frame metals (linked again here).

For comparison, I’ve ridden a few all-steel drop bar touring bikes and logged some substantial saddle time on my ti Bearclaw Hardtail MTB; I found the ti Fenrir to feel noticeably smoother than any all-steel bike that I’ve ridden and on par with the Bearclaw. The stainless frameset (with Enve’s Mountain Fork) will set you back $2,050; the titanium option will cost you $3,550.

I’m 5’7″ and received a Medium frame to test from Otso—consistent with my typical 54cm frame size—set up with flat bars and Enve’s rigid Mountain Fork, and outfitted with SRAM GX AXS, but I was keen to start fiddling with the more readily swappable parts. For anyone who remembers their high school biology days, with all of these configuration possibilities it seems like one could make themselves a little Punnett Square to map out the different setups for the Fenrir, with the X-axis being drop bars or flat bars, and the Y-axis being a rigid or suspension fork. But, like the probability of certain trait outcomes, I found myself being more likely to use certain pairings than others.

What’s in a Name: The ATB Conundrum

“People will do anything to avoid riding a mountain bike.” Adam Sklar said that, and he said I could quote him as saying that here. (For semantic purposes, it was understood in this context that we were talking about modern mountain bikes with either front and/or rear suspension.) We were on a coffee ride in Boulder, CO, and the conversation had turned to the ATB phenomenon. I immediately felt validated, because, after a few months riding the Fenrir set up with a rigid fork and swoopy bars I was feeling less-than-plussed.

I received the Fenrir in the late summer of 2022 and immediately swapped out the provided Race Face flat bars and threw on the Surly Corner to mimic a true drop bar setup.My two most-commonly ridden bikes are a Rodeo Labs Trail Donkey 3.1 (carbon drop bar bike that clears up to 700 x 55mm/48mm front and rear, respectively) and a titanium Bearclaw Hardtail MTB with a 120mm suspension fork as reference points, the rigid drop bar Fenrir as “ATB” wasn’t doing enough for me in either of these two categories it attempted to merge.

The fact that Otso positions the Fenrir as straddling both the Gravel and Mountain categories, and encourages drop or flat bar use, initially had me inclined to call it an ATB, or “All Terrain Bicycle.” Whether you’re on board with the term or not, it’s one that bike-makers (though not Otso) are adopting as an attempt to pigeon hole this tweener sub-niche of frame styles. They’re not sleek and svelte Gravel bikes made to crush watts on smooth county roads, but they’re also not made to go full-tilt on more technical trails.

Regardless of how you see the modern ATB as having evolved—as an outgrowth of the gravel trend (or rather, a counter-cultural naming knee-jerk against the commercialization of it), a response to the uptick in bikepacking’s popularity, or as a resurgence of early-MTB designs—I’d argue that today these frames are touted as the elusive “one bike quiver” or all-rounders for off-tarmac riders.

I mean, it’s all in the name, right? All Terrain Bicycle. But, as any generalist is quick to self-deprecatingly quip, having a wide scope of skills but relatively shallow level of expertise in any given one makes you a jack of all trades and a master of none. It’s the middlingness of this design approach that irks me a bit when it comes to ATBs and, in this first rigid-forked-swoopy-bar configuration, the Fenrir.

It is my experience that the type of terrain these style of bikes actually excel on are somewhat niche when the miles start stacking up. But, as Carmen Aiken put it so simply and concisely, “Sometimes being on a bike and singing quietly is better than just having to talk about them all the time.” So I stopped thinking about where the Fenrir sans suspension should sit in the fluid and ethereal schemas of frame designs and I went out and rode the damn bike.

Rigid + Swoopy Bars

With this gravel-oriented facsimile in place, I took the Fenrir on two far-flung trips. An invitation to a press camp in Gunnison, CO provided the perfect opportunity for me to log some fast-gravel miles. While I was obliged to spend most of my time during the actual media event on a Revel Rover demo, I decided to take advantage of the waning window of alpine season and add a 180-mile overnighter onto the back end of my time in Gunnison. I’d done some riding around central Colorado’s Sawatch Range before but had never visited Crested Butte or really gotten an up-close look at the Elks.

The riding was superb; it’s no wonder that the lure of exploring such iconic routes as the area’s famous Pearl Pass inspired a shift in bike design thinking. While my route didn’t cover Pearl Pass (I’ll most certainly be coming back for it), I took the Fenrir up-and-over a handful of smoother, high gravel passes—some known to me, others previously untread.

Above Photo: Emma Brophy 

While I felt endeared to the Fenrir for joining me on this solo late-summer sojourn, I did become aware of a couple of annoying traits, as you do after spending a prolonged period of time with any traveling company. I packed minimally for the trip as a friend in CB had offered me their guest room for my one night out (thereby eschewing the need for a sleep system). Still, I found the Corner Bar’s (46cm) compatibility with a front load to be a little limiting, and given the Fenrir’s heavily slanting top tube, my frame’s inner triangle capacity was reduced, as compared to a drop bar touring bike. As I’d later learn, you’d have to get creative to carry much more than a minimal setup.

My most notable knock against the bike itself though harkens back to my general qualms with ATBs’ lack of specialization, as stated above—on any prolonged climbs, like the 12-mile/2,700’ trek from Pitkin to Cumberland Pass, the bike’s climbing efficiency felt lacking. For me, the albeit comfortable easychair position of the Fenrir was not compelling enough to stave off the thought during the last few miles of the climb, “Can I just get there already?” and make mental comparisons to how differently (read: slowly) this bike ascends an average 5% grade compared to my Trail Donkey or Crust Bombora.

Where I found this setup shined was in a seven-mile stretch of flowing, mostly smooth singletrack that took me out of Gunnison to start my route; it was also a joy on pass descents, though for these relatively tame surfaces in particular, the more relaxed geo did not feel especially warranted as compared to a drop bar gravel bike.

A cursory glance at the geometry of my two drop bar bikes versus the Fenrir doesn’t make the Fenrir’s relatively pokey pace on the ups and planted stability on the downs a surprising revelation—the Trail Donkey and Bombora share the same seat tube angle (73°) and have a one-degree difference in head tube angle (70°and 71°, respectively). By contrast, the Fenrir (size Medium) is built around a 68° HTA and a 75° degree STA, and has an expected taller stack and longer wheelbase than either of these sportier drop bar steeds. In short, if the Fenrir was indeed your all-in-one bike, it is more than up to the challenge of this type of smoother dirt riding though if I were to revisit this route, I’d certainly choose either of my larger-triangled, drop bar bikes for their improved responsiveness on long, gradual climbs.

After this initial all-in first date with the Fenrir, and receiving many compliments on the bike from friends back home, I was feeling a bit of imposter syndrome whenever I’d hop aboard—for the Freaks and Geeks fans, like Lindsay Weir trying to play it cool around Daniel and his edgy crowd—while in reality, the creeping suspicion was forming: maybe I’m just not chill enough to ride an “ATB.”

On the tail end of an east coast road trip a few months later, I had the pleasure of joining in the fall festivities at the 2022 Nutmeg Nor’easter. After spending the majority of the trip focused on running and climbing the two-day campout was a welcome return to pedaling, and my first taste of New England riding.

Center Photo: Adam Sklar

Ronnie and Arya could have hardly orchestrated better weather for the Nor’easter’s kick-off. We rode under a clear autumn sky and warm sun—the kind of gloriously perfect conditions that almost lull you right out of riding and right onto the closest patch of soft grass. Amongst the old, weaving carriage roads, tight turns and leaf-strewn links, the Fenrir outfitted with the Corner Bar and 700×55 Rene Herse Fleecer Ridges felt right at home. On our route at least, the terrain was most always changing—we were either transferring from a sneaky cut through the trees onto dirt, cresting a short climb, or buoyantly careening down another—and in this chill setting, the Fenrir’s more relaxed position didn’t feel like a hindrance. While my general feelings about the Corner Bar’s lack of hand positions/long-ride comfort echo Travis’ review, but on the skinnier, bumpier stuff—and two sub-40-mile rides—it piloted the bike quite well.

Suspension Fork + Flat Bars

If you’ve stuck it out with me this far, take heart in knowing that the Fenrir as a hardtail was a bike I could see myself riding A LOT. Specifically, as a bikepacking hardtail. My partner, Tony, and I have made an unintentional habit of taking a desert trip in the early months of the year, for the past few years, and the Monumental Loop had been on our minds for some time. We’ve always hoped to make it down to the Dangerbird but so far we’ve struck out on getting to Las Cruces for the actual event. So, this February we set out sights on touring the full route.

After hearing about all the chile and chonk on the route, I opted to use our early-season tour to test the Fenrir with some front suspension. I borrowed the RockShox SID Ultimate 120mm fork from my Bearclaw—along with my Whisky No.9 Bars (with some inboard grips and bar ends, detailed in the Build Spec) and Thomson stem—threw on a pair of 2.8” tires (Otso’s stated clearance for the bike is 700×2.6″ but concedes that some larger tires do work in the frame), and a rear rack before loading it up with bags. While the set up was simple thanks to the Fenrir’s seat stay rack mounts, I’m aways a bit nervous about running metal hardware on such rowdy terrain as is characteristic of the Monumental Loop. Still, I’m more loath to put a ton of weight on the front of the bike (via a bar roll) when riding a hardtail for handling purposes and at some point you have to find somewhere for your stuff to go. On a less climbing intensive route like the Monumental Loop, I didn’t find much issue with biasing more of the weight over the rear wheel. This rear rack plus dry bag and bottle cages worked great (I’d done the same thing the year before when touring the Stagecoach 400 route) though I wouldn’t take it on a burlier route like the Colorado Trail.

Loaded down and booted up with wide rubber kind of feels like cheating when trying to assess a bike’s handling on rougher terrain. However, the 15-mile Sierra Vista Trail section and the preceding singletrack on either side of Las Cruces felt like an honest test of the bike’s agility and a turning point moment in my appreciation for the Fenrir. The Sierra Vista Trail skims in a roughly north-to-south line on the west side the Organ Mountains and bobs in and out of steep, punchy, sometimes sandy, drainages for most of the way. Throughout this rollicking stretch of trail, I felt perfectly in sync with the bike—rather than wrangling it to do what I wanted—and was impressed by its responsiveness when transitioning out of a descent into a stoutly graded kicker.

I’ve ridden my Bearclaw on similarish-ly rolling terrain with mixed results. I was surprised to find that the Bearclaw and Fenrir share very similar geo, with seat tube angle being the most stark deviation, and the Bearclaw also having a slightly longer front center. The Bearclaw’s 73° STA often has me feeling too much in the backseat on punchy climbs or moving over features on short uphills. While I’ve been into the longer-distanced drop bar stuff for about five years, I’ve only been riding bikes with suspension for a year and am still learning all the tricks of body English. The Fenrir’s steeper 75° STA made it feel much easier for me to move my weight around on the bike, particularly on short, sharp pitches. I also found that the Fenrir seemed to handle much better than the Bearclaw with (an albeit small) front load and was happy to find none of the dreaded drunk goat wheel flop on the Monumental Loop’s slow, loose climbs. Otso’s promise of the bike being built for bikepacking was bearing out…

Rigid Fork + Flat Bars

Admittedly, this was the configuration I rode the least but only because of time and weather constraints. It has proved to be a very snowy year in the Mountain West and my immediate backyard trails have been in hibernation mode and, at some point, I needed to send the bike back!

On a few short local jaunts, I appreciated the extra leverage of flat bars paired with the Fenrir’s readiness to climb the steep stuff. While the bike isn’t made for the many long, sustained dirt climbs we have here in Colorado, it runs merrily up truly precipitous techy terrain. It may not be a fast marathoner, but this bike can sprint on the steep stuff. Otso/Wolf Tooth also sent me the newly-released Wolf Tooth Resolve Dropper on the latter end of my time with the bike. I found the action to be reliable and smooth with consistently powerful return.

TL;DR: Major Take Aways

If you’ve spent the better part of this review wondering if or why bike categorization matters at all, by way of response I would say the very unsatisfying “they do and they don’t.” I believe that calling the Fenrir a hardtail, or MTB, is more apt than calling it an ATB (or worse, a capital G Gravel bike) because it more accurately calibrates the would-be rider’s expectations. While I wouldn’t go so far as to say it’s inappropriate for Otso to stick the Fenrir under the Gravel bucket on its site, I would say that it’s not wholly necessary as, in my mind, the Fenrir is a hardtail that you can set up rigid or not with a range of bar styles. I think it’s pretty obvious to intuit that you can ride a hardtail on gravel but a hardtail is not a gravel bike; whereas I don’t think you should peg a Gravel bike as also a mountain bike. The design flow, here, only moves in one direction: a square can be a rectangle but a rectangle can’t be a square kind of logic. This bore out for me when testing the Fenrir in a rigid drop bar configuration on terrain that I would typically ride on either of my drop bar Gravel bikes.

Still, the reason I would say that bike categorization doesn’t matter is because, at the end of the day, a bike is a sum of its geometric and interchangeable parts and the most winning equation for me proved to be as a bikepacking hardtail. If the Fenrir were to find a permanent home in my stable, I would keep it set up in the hardtail iteration that I enjoyed so much on the Monumental Loop as, for my riding preferences, this bike performed best when taking one more step towards the MTB side of the off-road spectrum.

Pros

•A truly capable bikepacking/touring hardtail: ample rack and bottle cage mounts, a versatile platform, and handles well under load.
•Offers the rider a range of setup options
•Compliant, super durable, long-lasting titanium material/construction

Cons

•Spendy; more so than the stainless version
•Not a “gravel” bike (obviously, a very subjective judgment)

Build Spec

Year: 2022
Frame: Otso Ti Fenrir (Medium)
Fork: Enve Mountain Fork / RockShox SID Ultimate 120mm Fork
Bar: Race Face Ride 740mm / Surly Corner Bar 46mm / Whisky No. 9 720mm
Stem: Aluminum 60mm +/- 7 deg / Thomson X4 40mm
Grips: Wolf Tooth Fat Paw / ODI x Vans LOCK-ON / Ergon GP3 BioKork (inboard Specialized bar ends)
Headset: Wolf Tooth
Shifters: SRAM GX AXS
Rear Derailleur: SRAM GX AXS Eagle
Cassette: SRAM 10-52t GX
Brakes: Magura MT4 Hydraulic Disc + Levers /
Cranks: Race Face Next SL Boost 170mm
Pedals: Issi Flash II
Wheelset(s): SUNringle Duroc Comp 30 / Knight Composites 29″ I-30 USA
Tires: Maxxis Aspen 29×2.4″ / Rene Herse Fleecer Ridge 55c / Teravail Coronado 29×2.8″ (measured 2.7″)
Seatpost: Fox Transfer Performance with Wolf Tooth remote / Wolf Tooth Resolve
Saddle: WTB Volt / Brooks C13 carved / Brooks B17 carved

Alternative componentry is listed in the order it appears in the article (i.e. original build kit from Otso, rigid/ drop bar setup with the Corner Bar, hardtail setup).