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  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
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  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
  • Borealis Bikes Telluride GX Eagle/Mastodon Fat Bike Detail
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Borealis BikesTelluride GX Eagle/Mastodon Fat Bike
Sale 20% Off$2,360.00 $2,950.00

Item # BOR000Y

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  • Gloss Metallic Grey/White, XL ($2,360.00)
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Item # BOR000Y

Telluride GX Eagle/Mastodon Complete Fat Bike

Set in a high mountain valley surrounded by the towering peaks of the San Juan range, Telluride is an iconic Colorado mountain town littered with trails, including winter fat biking trails accessible right from town. It's a favorite spot for the crew at Borealis bikes and a fitting name for their versatile new fat bike that's built with adventure in mind. Like their other fat bikes, the Telluride GX Eagle/Mastodon Complete Fat Bike floats effortlessly across snow, sand, and loose surfaces. But with 27.5in fat tires, a narrower Q-factor, slacker geometry, and 120mm of travel up front, the Telluride is built to conquer any trail, all year long with a newfound haste. Whether you're ripping around on packed snow, saddling up for a multi-day bikepacking trip, embarking on a coastline tour, or lapping your favorite bit of singletrack, the Telluride gets the job done without skipping a beat.

The Telluride's adventure-ready attitude comes from a number of trail-optimized features that make it more versatile than your typical fat bike, and thus more suitable for day to day riding in addition to winter excursions. The hydroformed aluminum frame is designed around 27.5in fat bike wheels and has enough clearance for tires up to 4.5-inches wide. 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 hardpack surfaces. This design also allows Borealis to give the frame an 83mm wide bottom bracket shell instead of the standard 100mm shell found on most fat bikes. The result is a significantly narrower Q-factor, which makes your pedaling stance closer to the width of normal mountain bikes for improved efficiency and better comfort on long days in the saddle. The narrower stance also makes it easier to shift your weight to steer the bike, as it reduces the abrupt turning transition feel of wide Q-factor fat bikes.

Borealis gives the Telluride a slacker head tube angle and longer reach compared to the Crestone or Flume models, lending additional stability on descents and faster sections of trail. This progressive geometry pairs well with the 120mm travel Mastodon fork up front and helps you make quick work of challenging terrain when the trail points downward. When it's time to pedal back up, the wide gear range and 50t bailout gear of the SRAM GX Eagle drivetrain ensure you'll always have the right gear for every climb, along with crisp shifting, quiet operation, and infallible chain retention. Other features include integrated rack mounts for carrying extra gear while bikepacking or touring, a carbon handlebar and seatpost, and Race Face's coveted Next R carbon crankset to power you forward with lightweight efficiency.

  • A 27.5in fat bike with an adventure-ready attitude
  • Narrow Q-factor improves comfort and efficiency
  • Slacker and longer geometry lends stability at speed
  • 120mm travel fork for improved descending capability
  • Integrated rack mounts for bikepacking and touring
  • Hydroformed aluminum frame is lightweight and resilient
  • Next R carbon crankset for effective power transfer
  • GX Eagle drivetrain offers wide gear range, crisp shifting, and unwavering chain retention
Tech SpecsGeometry
Tech Specs
Frame Material
6066 aluminum
Manitou Mastodon EXT Pro
Front Travel
SRAM GX Eagle 12-speed
Rear Derailleur
SRAM GX Eagle 12-speed
Race Face Next R Carbon
Chainring Sizes
Bottom Bracket
Race Face BSA30
Bottom Bracket Type
BSA threaded 83mm
SRAM XG-1275 GX Eagle 12-speed
Cassette Range
10 - 50t
KMC 12-speed
Brake Type
hydraulic disc
Borealis Carbon Bar 35mm
Handlebar Width
Ergon GA30
Stem Length
[small - large] 50mm, [x-large] 70mm
Borealis Carbon 31.6mm
Seat Collar
[rims] Sun Ringle Mulefut 80mm
Front Axle
15 x 150mm thru-axle
Rear Axle
12 x 177mm thru-axle
Terrene Cake Eater
Tire Size
27.5 x 4.0in
not included
Recommended Use
Manufacturer Warranty
5 years on frame

120mm Travel Fork

a Seat Tube
b Effective Top Tube
c Stack
d Reach
e Stand Over
f Head Tube
g Head Tube Angle
h Seat Tube Angle
i Bottom Bracket Height
j Bottom Bracket Drop
k Chainstay
l Wheelbase
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