Review: Borealis Yampa Carbon Fat Bike

Hot on the heels of my long-term Fatback review, I had a chance to demo the new Borealis Yampa carbon fiber fat bike at Outerbike.

I … like … big bikes and I cannot lie …

Borealis is fairly new to the fat bike scene and is the brainchild of Adam Miller and Steve Kaczmarek, with design input from seven-time Iditarod Trail Invitational race winner Pete Basinger. Adam comes to the fat bike biz by way of and 9:Zero:7, both based in Alaska, and Steve brings his business acumen and investment weight to the mix. Pete has been riding, designing, and working on fat bikes since before they were cool.

Anyway, enough marketing crap… how was the bike?

Glad you asked!

So the Yampa is the first product offering from Colorado Springs-based Borealis, and features a full carbon frame that can be built as light as 21 pounds with top of the line component choices. You read that correctly: a 21 pound fat bike.

The model available for demo at Outerbike was the $3,599 X0/X9 build level and sported a pair of 4.8″ tires. There is also an XX1 build option for the opulently wealthy, single chainring crowd.

Throwing a leg over the Yampa, the first thing I noticed was the fairly high top tube. Standover is always an issue for me as I have a pretty short inseam, and the size medium test model was roughly equal to my Anthem X 29er. However, with the boys off the top tube and my feet clipped in, it was immediately apparent that this is a very, very light setup and is way more nimble than a fat bike has any right to be. The rolling mass of the fat wheels is what it is, but Borealis has seriously lightened up the frame by going to carbon, which is also as stiff as you’d expect.

Since I’ve ridden another fat bike extensively, heading out to the Moab Brand Trails demo loops I had some expectations concerning handling over rocks and ledges, as well as flotation over sand. The Yampa performed as expected, with the added bonus of the cush provided by the extra-fat 4.8in tires combined with the muting properties of the carbon frame. Overall, the Yampa is a playful and responsive bike. You’d be forgiven if you temporarily forgot you were actually on the bike equivalent of a monster truck.

Handling and trail manners aside, the bike had a couple of annoyances that would be very aggravating on a long ride. First, the brake caliper is mounted inside the rear triangle, forcing the chain and seat stays to flare outward quite sharply in order to maintain alignment with the rotor. I have size 9 feet and my heels brushed the chainstays a bit, and I assume anyone size 10 or larger will notice this even more. Secondly, the first time I got out of the saddle to pedal up a hill the seatstays drove into my calves HARD. I mean OUCH! hard. Now, I know I have some particularly manly calves, which is also an issue with my ski boots and some other bikes, but this was surprisingly severe. Unfortunately, these two issues make the Yampa a no-go for me, but of course your mileage may very, especially if you are of a lankier build than I. (I’m looking at you, Jeff B.) 😀

Bottom Line

With the Yampa, Borealis has come out of the gate swinging. The weight, feel, and aesthetics are awesome, but for it to be a workable fat bike solution for us stockier riders, I think the top tube will need to drop and the rear triangle will definitely need to get narrower. This bike is a solid first effort from my home state of Colorado, and I am stoked to see what subsequent models bring to the table!