Borealis Bikes

Yampa XX1 Complete Bike

When it came time to design the Yampa, the team at Borealis drew from years of experience at the bleeding edge of fat bike development and a desire to build the best possible tool for the job. You see, these guys have been riding fat bikes since it involved welding together pairs of standard width rims, so they've seen fat bikes develop from their infancy. Borealis adopted new standards for components and construction in hopes that it could deliver a product that improved on the competition in every measurable way, and with builds coming in well under 30 pounds, we'd have to say that they've hit their mark. And it's not just the light weight that makes the Yampa so appealing. With its proven XX1 drivetrain and Surly rims and tires, it's downright bulletproof too. Welcome to the high tech fat bike revolution.

Borealis built the Yampa frame using the most up to date carbon fiber construction methods. Beyond shedding grams, the composite construction has enabled Borealis to finely tune the flex and build a strong frame that will hold up to year 'round use. The profiling of the seatstays in particular enables added vertical compliance, while the oversized chainstays keep the pedaling responsive when you stomp on the gas. Tire clearance was paramount, and accordingly, the Yampa is able to clear massive 4.8 inch tires on a 100mm wide rim. To achieve that degree of clearance without resorting to a weaker offset wheel, the Yampa uses a Borealis 190mm spaced rear hub. The result is a dishless rear wheel, perfect drivetrain alignment with the 100mm threaded bottom bracket shell, and more than enough clearance for the drivetrain regardless of your tire choice. Naturally, there's plenty of extra clearance for mud, snow, or anything else you're likely to find yourself riding through. The head tube is a tapered affair, which yields incredible stiffness when paired with Borealis's thru-axle equipped carbon fiber fork. It's equipped with three bottle cage mounts, to keep you hydrated for long hours in the saddle. And at 1270 grams for a medium frame, this just may be the lightest fat bike frame in existence.

SRAM's XX1 drivetrain got the nod for the Yampa's top-end build. It forgoes the front derailleur in favor of a wide range 11 speed cassette, which offers a nearly identical range to a standard double chainring equipped drivetrain. The crankset is a Raceface Turbine 100mm setup, with a narrow-wide tooth profile that offers all the chain retention you could ask for, even without a guide. SRAM's XX brakes handle stopping duties, and the cockpit is primarily Truvative hardware with a WTB saddle and Ergon grips. The wheels are Borealis's own hubset, featuring a 190mm quick release rear and a 135mm 15 QR thru-axle front hub. They're laced with double butted spokes to Surly Marge Lite rims, wrapped in 3.8 inch Surly Knard tires. It all adds up to a blisteringly fast snow-race bike, that you'll still want to ride long after spring has come around.

The Borealis Yampa XX1 complete bike is available in four sizes, from small to extra-large, and in the colors Black/white, and Black/red.

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