We’ve got a wonderful Readers’ Rides today, that doubles as a review, sent in from our buddy Jason Fitzgibbon, who submitted his UNpaved Cycles Vertigo single pivot steel full suspension. Read on as he supplies a beautifully documented review of this bike…
My love of steel bikes began nearly twenty years ago with a fully custom Independent Fabrication single speed. Man, I fucking loved that thing. For months prior to ordering it I had toiled over every angle of the geo, the color, the logos, the parts spec, everything. I put so many damn miles on that thing (surely burning through significant amounts of patellar cartilage in the process), and never once did I finish a ride on it without absolutely smiling my ass off. That bike spurred a near decade’s long obsession with steel frames; a Dean single-speed, Sycip cross bike, LeMond road bike, VooDoo XC bike, Ibis cross bike, On-One single-speed, All City fixed gear, and plenty more that I can’t currently recall. They were all subjectively rad, distinctly weird and objectively fun to ride; each one in its own right.
Fast forward another decade and all that I’ve been riding are mass-produced aluminum and carbon full suspension bikes. They’re fast, they’re fun, but more than anything they are a means to those two ends. I absolutely love how they’ve enabled me to expand and progress my riding, but over the last few years I’ve been realizing that the quirky bike nerd in me has been getting the short end of the stick. I missed having a one-off bike, knowing exactly who made it, playing some form of a role in its design, and most of all, I missed having something durable and timeless. Honestly, I have also grown quite tired of carbon’s fragility and the perceived obsolescence of anything that’s more than a couple of years old. All of that being said, I was in no way willing to go back to hardtails to fulfill those needs; I wanted something steel, something unique, and I needed it to be squishy on both ends.
One steel full-suspension frame builder in particular had piqued my interest since I first stumbled across one of his bikes online three years ago; Michiel Burgerhout of Project XII cycles. Based out of the Netherlands, his bikes possess a highly detailed yet simplistic aesthetic that much appeals to my custom steel hardtail roots. Clean lines and extremely thought out – yet not overly complicated – designs carry through his various models. Specifically, his relatively aggressive trail bike model, the Vertigo, really appeared to cater to my riding style. It implemented a tried-and-true rocker link design and flex stays to achieve 140mm (or 125mm, but more on that later) of travel. It’s simple, it’s clean, it looks svelte as hell.
When I finally reached out to Michiel in late 2023 to inquire about ordering one, he spilled the beans on a new endeavor he was just beginning to undertake; UNpaved Cycles. His new brand would leverage – and in some cases improve upon – his beloved Project XII designs, but would utilize some fresh takes on 3D printed lugs and more welding (as opposed to exclusively brazing) to make small batch production numbers more achievable. My heart sank when he initially admitted that he was just getting going on some of his very first Unpaved prototypes, and was not intending on building up the first UNpaved Vertigo for some time. And then, within a matter of a few sentences, went on to say he would gladly build me a prototype if I was interested. Damn straight I was!
So the process commenced; regular and enjoyable email correspondences with Michiel shot back and forth, as he kept me in the loop (and dare I say, involved with design decisions) and locked in on the final geo and configuration of his new UNpaved Vertigo model in a size XL. In the end we both agreed 64.5 degrees was a great all-around head angle for an aggressive trail bike, and that a 76.5 seat angle was perfect for all-day rides and long climbs. Reach is on the moderately long side at 500mm for an XL, the BB height sits at a crowd-pleasing 340mm, and 455mm chainstays occupy that really happy space between jibby and stable for a size XL.
Michiel worked up a gusseted head tube that can easily handle long and stiff-legged forks ridden aggressively, and the gusseted seat tube keeps stand over low without necessitating a vulgar amount of exposed seat post for crazy high inseamed freaks like me. Michiel’s beautifully designed, 3D printed chainstay yoke and UDH compatible dropouts round out the rear end (he had mentioned that these might change slightly as he finalizes the design). And barely noticeable on his renderings were the elegantly tapered and ovalized seat stays, shaped as such to flex very slightly at a determined point not far above the 3D printed drop out lugs.
The CNC’d rocker link drives either a 55mm stroke trunnion mount shock for 140mm of rear wheel travel, or a 50mm stroke shock of the same eye to eye length for 125mm of rear wheel travel. The former setup mates best with a 150mm fork, the latter with a 130mm or 140mm fork, which steepens the head angle and seat angle up to a degree and lowers the BB up to 7mm.
As Michiel pieced the frame together bit by bit, he continued to send in photos and updates of the process, and as he neared completion it came time to pick a color. As an ecologist, I am regularly inspired by the ephemeral hues and shades of the natural world around me. One particular color that I almost always wish I could cling to for longer than the few months it persists in our local scrub is the iconic gray/green of fresh spring leaves on California sagebrush. So, I went with RAL 6013, my best attempt at honing in on that fleeting hue of Southern California spring.
When the frame finally arrived here in California, I was awestruck by the attention to detail and craftsmanship exhibited by Michiel’s pre-production iteration of the UNpaved Vertigo. The welds on the Reynolds 853 tubes were flawless, the brazed and hand polished branding was beyond stunning, and the semi-gloss powder coat was spot on. The CNC’d rocker link and pivots were beautifully executed, and the 3D printed yoke and dropouts gave the bike a very finished, production-level look.
For the build I started with cable-actuated Shimano XT drivetrain components throughout, Shimano XT brakes and Shimano XT trail pedals. For our burlier trails I’ve equipped the bike with a Fox 36 GripX 150mm in Podium Gold (a SoCal autumn-inspired compliment to the sage green), with a 45mm stroke Fox Float X in back. For longer, mellower days or bike-touring jaunts I’ve got a Fox 34 140mm up front and a 40mm stroke Fox Float shock. For the wheels I went with Roval’s incredibly light Control Carbon 30mm offering – I’m a big fan of snappy acceleration. A polished silver Chris King Headset, silver Absolute Black chainring and silver Deity seat collar accent the hand-polished logos and UNpaved branding. I felt the gumwall Specialized Butcher tires and grips were mandatory on this thing.
First impressions:
My first outings on the bike were in some chunky, janky backcountry Utah singletrack. The climbs were steep, rough and lacking oxygen, so it was to no surprise that I felt that I noticed the additional pound and a half or so I was carrying uphill over my last carbon bike. That being said, the flex stays impart a very efficient transfer of power, and the bike does not wallow or sag into depressions or obstacles when you need to put power down. The seat angle and reach are absolutely perfect for my shape and stature (a lanky 6’2”), and I immediately felt very comfortable climbing on the bike, despite the heavy breathing.
Once pointed downhill, holy hell does this thing rip. Never mind those tiny seat stays and lack of a Horst-link pivot, the bike has sufficient lateral stiffness to track and hold a line, while swallowing up small and big bumps alike. When you stand up on the bike to attack a descent, it predictably sits into the top third of its travel and does very well to match the progressivity and mid-stroke feel of the Grip X damper up front – a centered and balanced feeling that very quickly urged me to drop my heels and let off the brakes. It’s as sure-footed as any modern carbon trail bike I’ve ever had, yet has that subtle, buttery damping of trail chatter and vibration thanks to the steel (a trait that oddly enough, has allowed me to run higher tire pressures without sacrificing traction or comfort…who would’ve known??).
Michiel has worked up kinematics that provide a much-appreciated ramp up at the end of the stroke, and in my few weeks of riding it I have yet to feel the bottom, despite regularly using all of its travel. Very much to my surprise, and my liking!, the bike in this fork/shock iteration is fast, quiet, and planted on the descents. I recently owned a 2023 Specialized Stumpy Evo, and the UNpaved Vertigo descends very similarly to that bike in the neutral or slack HA setting.
After a few weeks of riding the bike in its longer travel mode, I swapped out the shock to a 40mm stroke Fox Float (125mm travel) and a 140mm Fox 34 Grip X. With the 0.5 degree steeper head and seat angle, in combination with the firmer climb switch on the Float, the bike climbs with MUCH more fervor. It is surprisingly efficient, and sits high in its travel with a seated position that prompts you to attack technical and punchy climbs, and feels plenty comfy for long, seated efforts. Almost immediately I noticed the lack of fore and aft saddle movement required to maintain power and traction on steeper sections – a feeling that I rarely ever get to enjoy on full suspension bikes since my seat height is so damn high (which makes my actual seat angle on most modern-kinked-seat-tube FS bikes waaayyy too slack for steep climbing).
Descending the UNpaved Vertigo in short travel mode is also entirely different, in a good way. With its shorter stroke, the rear end ramps up much faster, providing a much poppier ride that mates well to the 34’s smaller volume air cartridge that does the same. On chunky fast stuff, the difference between the two travel settings is quite obvious, with the short travel being more inclined to hang up on things rather than just plow quietly through.
On lesser gradient trails however, the “little” bike holds more speed than in its longer travel setting, providing more to push off of in corners and depressions. That ability to carry speed also allows it to get in the air with less effort, and in general conveys a much more playful feel, which is exactly what I was hoping for with the bike in this setup. And somehow that same bottomless feel is there, so even with some unplanned hucks to flat I have yet to hear it clunk.
Build Spec:
- 2025 Fox 36 150mm, Podium Gold, GripX, no volume reducers
- 2025 Fox Float X, 55mm stroke (140mm), no volume reducers
- 2025 Fox 34 140mm, Gloss Black, no volume reducers
- 2025 Fox Float, 50mm stroke (125mm), no volume reducers
- Fox Factory Transfer 30.9mm x 210mm Dropper
- Shimano XT 4-piston (BL-M8020) brakes
- Shimano RT-MT905 rotors (203F/180R)
- Shimano SL-MT800-IL remote dropper lever
- Shimano XT FC-M8100 crankset
- Wheels Manufacturing T47 BB
- Shimano XT Trail SPD pedals
- Shimano XT FC-M8100 chain
- Shimano XT 10-51T cassette
- Shimano XTR 12spd rear shifter
- Shimano XT 12spd rear derailleur, medium cage
- Specialized Bridge Mimic saddle, 143mm
- Absolute Black 30t elliptical chainring, titanium
- Roval Control Carbon 29” Wheels
- Deity 34.9mm collar, silver
- Wolf Tooth ti bottle cage
- Specialized Butcher 2.6 T9 Front Tire / Specialized Butcher 2.3 T7 Rear Tire
- ENVE M6 Bars
- ENVE Vorbau 35mm Stem
- AMS Berm grips, tan
We’d like to thank all of you who submitted Readers Rides builds to be shared here at The Radavist. The response has been incredible and we have so many to share over the next few months. Feel free to submit your bike, listing details, components, and other information. You can also include a portrait of yourself with your bike and your Instagram account! Please, shoot landscape-orientation photos, not portrait. Thanks!