Borealis Bikes

Crestone GX Eagle/Mastodon Fat Bike

Over the years fat bikes have gained a reputation as the slow, plodding adventurer of the bicycle world, but Borealis blows that old stereotype out of the snow with the Crestone GX Eagle/Mastodon Complete Fat Bike. Pairing a stiff carbon fiber frame, plush 27.5in fat tires, a Manitou Mastodon suspension fork, and SRAM's workhorse GX Eagle groupset, this bike is a lightweight and versatile steed chomping at the bit to take on snowy trail adventures and beyond. Tell your other bikes they'll be getting a lot of rest this winter, layer up, and head out into the wilderness.

Borealis built the Crestone frame using cutting-edge carbon fiber construction methods to finely tune the ride quality, resulting in a lightweight yet impressively strong frame that will hold up to heavy use. That's particularly important since the addition of the 100mm travel Mastodon invites you to take more difficult line choices. Nimble handling and low weight are helpful attributes on fat bikes, and you'll appreciate pedaling around the Crestone with its lightweight carbon fiber frame and quick-handling geometry. Not unlike an XC race bike, Borealis gave the Crestone a relatively steep 70-degree head tube angle and a shorter reach to keep you in a comfortable position and help quicken the steering of that big wide front tire. The geometry is also well suited for bikepacking and touring, helping you cover ground quickly and efficiently.

This Crestone is built up with 27.5 x 4.0in tires on 80mm rims, providing a solid platform to roll on snow or loose terrain while remaining sprightly compared to extra fat and voluminous 26 x 4.8in fat bike tires. 27.5in fat tires have shorter sidewalls than their 26in fat tire counterparts, contributing to more precise cornering, less tire bounce, and a faster feel on packed snow or moderately loose terrain. This gives the Crestone an even livelier feel with improved rollover characteristics, though you can always switch to some fatter tires later on if you need maximum flotation for fresh snow or deep sand.