First Ride – Borealis Carbon Fat-bike

Folks, we are pre-empting our normal Wallpaper Wednesday to bring you this special report. Wallpaper Wednesday will resume next week at it’s regular time.

On with the story!


Colorado Springs is the home of Borealis Bikes and also the home of our bud Sevo who had a chance to take a pre-production Borealis Fat-bike out on a shakedown cruise on the Colorado trails new home base. Here is his report:

Written by Sevo!

For years steel was the only real option for a fat-bike. Then Salsa, 9:Zero:7, and a host of others brought out beautiful aluminum bikes (My first rig was aluminum, loved it). The progression to carbon is not unique to Borealis as we all know, Salsa showed off their prototype… off is probably not the right phrase, a very controlled sneak peak at best. However, that was all it took to get the wheels turning in the industry.


Enter Borealis Bikes

While not first to the scene to unveil a production carbon bike, it looks like Borealis will be the first to deliver with their first shipment of framesets scheduled to land in Mid-August while Salsa has neither confirmed nor denied when theirs will land. Lucky for me, living in the same town Borealis calls home, I’ve gotten a chance to get out on not just a prototype, but a pre-production bike and I have to admit, weight was my initial only excitement to try this rig out. But I’d soon learn weight savings was not the only incentive to pedal a carbon fat bike.

First off, Borealis Bikes is a new player to the fat-bike market but Adam Miller, co-founder, is not new to fat bikes. Growing up in Alaska and having worked with another notable and impressive brand for a few years, he proved to be a quick learner. Combined with a business partner a few years his senior with multiple start up experiences under his belt allowed them to skip the normal learning curves and move straight into production. Adam pulled off the design, made a trip to China, and had tests done all in under 6 months. The results are impressive.


Basic details are simple. Like many newer fat-bike brands, Borealis choose to go with a more traditional mountain bike feel vs the briefly touted “fat bike” geometry. Top tube is slung low, but not so low or curved weird to prevent the use of a frame bag. The rear end sports rack mounts. Chain stays and seat stays, flattened to aid bump absorption (my Salsa Chili Con Crosso has this as well…love it). Per industry standards these days, it’s set to run a tapered fork (theirs in particular and worth it). They do incorporate the new 190mm hub standard in the rear and the frame/fork cleared the 4.7” BFL’s mounted to 100mm Surly Clown shoe rims rather well with plenty of room.

Yet, I was happy to see that Borealis did not adopt one of the many press fit BB standards. No need to buy new tools or make a run to your LBS to get your bottom bracket in….Borealis is threaded for standard BB’s. Great considering the harsh conditions many fat bikes are used in can affect BB life. I prefer the idea of picking up a standard set of external cups or being able to run a Chris King BB vs special order bearings needing special tools. So fear not, your standard external cup bearing tool gets to stay in your toolbox at least one more season. A standard QR is used in the rear, and while armchair internet engineers may cry for a thru axle, it’s unwarranted on a hardtail….and the reason you do see it is because for race teams having only one rear wheel standard that works on both the hardtails and suspension bikes made sense. Otherwise it’s more marketing than need. Front however does utilize a 15mm thru axle, which helps get the fork weight down and allow a tuning of flex while keeping steering precision true.


Ride wise is pretty much what you would expect from a proper carbon bike. Just like a carbon road or MTB, it has that special snappy feeling a big old carbon reinforced bottom bracket shell delivers. On climbs I felt like I was on a fine road bike when I got up on the pedals, with the signature fat bike tire buzz reminding me I was not. Steering just felt a bit more precise than other rigs I’ve ridden, which I feel is more the geometry but sure the added stiffness of carbon deserves a wee bit of credit as well.


One thing I did question, even though I’ve liked it on my cross bike, was the flattened stays. Aesthetically, they do look rather pleasing and in your heart you know the purpose. But would it really matter on a bike with 4.7” wide tires? As I’ve stated in the past I haven’t felt even 3”-4” of rear suspension is warranted. So could flatted chainstays matter? Answer turns out to be a big old yes. While I wouldn’t say it’s like driving a Caddy, it did take the edge off some of the rougher Colorado trails I took it on and a worthwhile addition


It’s a tough bike to beat. Price is a competitive $2249 frame/fork. Weight is about 1250 grams for a medium frame) and 575 grams for an uncut fork, making it one of the lightest platforms out there, yet still has versatility with rack mounts molded in and room for a frame bag. Frame/fork have been tested to exceed industry spec, so no worries to be had.

More on borealis at:

If you’d like to see some of the Wallpaper Wednesday posts from the past – Check this out – Wallpaper Wednesday Gallery

About the writer: Sevo started riding/racing in ’89 and started selling bikes at the age of 16. Raced in the Midwest for 10 years for Adventure Cycle/TREK as well as Decorah Bikes/KHS. Owned a regional cycling publication in Colorado. Published in Mountain Flyer. Did Sales/R&D/wheel building at LEW Composites. Tested products quietly for many. Worked for Minoura at shows and raced snow races before their were fat bikes.

About Greg Smith 1127 Articles
Greg Smith, known to many site visitors as Sven Hammer, founded in 2011 and the site quickly became the #1 online community for all things Fat. You can currently find Greg outfitting Everyday Cycles; a Milwaukee, WI retailer of gear for fatbikers, adventure cyclists and urban assault riders.


  1. I wonder if this bike will work with a production suspension fork when one comes out next year? (please let there be one coming out next year!)

  2. I am not a fan of carbon, but this bike is challenging my perspective. I may need one in the near future. I am use to 40 lbs+/-, I can only salivate at the prospect of sub 26 lbs Fat. Time will tell, but I am encouraged with industry progression. Cheers

    • 40 lbs +/- is early fat ridiculous. We have been riding sub-30 rigs for a bit here up North. My current rig rolls around 26 with a 2×10 drivetrain. Until we get better hub and tire choices, I can’t see anyone hitting 23 or so with a full drivetrain and brakes.

      • 26lbs? What are you runnin to get it that light? Just built up a fatback and it came in around 31 and I thought that was pretty good. I would love to lose another 5lbs if possible but I think that it will cost a small fortune to do that. Granted, I didn’t go nuts building it but I didn’t go cheap either. Work in the industry and cost me probably 2300 when all said and done. Definitely penalized for the tubes and 27 TPI tubes but that is about all that is heavy!

  3. 38 frameworks has a handmade in USA carbon with enve tubeset. Custom sizing, lighter, and same price point!

    • Boomking-Actually look it up. They don’t include a fork and aren’t lighter. Plus I live in CO and didn’t see them at NAHBS in Denver this year or hear about them in the scene here.

      Also tube on tube construction is so 2003 🙂

  4. It’s silly to say what is “lighter” than anything else before we have production frames in our hands. Almost as silly as guessing when the QBP stuff will show up (or getting excited about that same old trick for the 90th product in a row… hint, they’ll take a while).

    • cyclocarbon-This is the pre-production frame, meaning a test run before you crank up the machine to 11. This isn’t another prototype. Currently it is the only production fat bike frame and you can order them.

      So, in short…this is real. 🙂

  5. The threaded BB is fine by me. I’m waiting on the new Beargrease but from what I’ve read about press fit BB’s & their noisy ways I’m a little worried.

  6. I’m happy to see another frame that can handle the Clown Shoe rims. I got a Moonlander in December and had just a small concern the tire size would be limited to that frame alone.

  7. I got to run one around the parking lot at Pedal Pushers in Golden Colorado and I’d echo alot of what the article has to say. ITs a great riding bike and very blown away at how light it is with the monster clown shoes. I very much want to own one 🙂

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