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Flume

Fatbiking adventurers know that inspiration matters, and a ride (or bike) is only as good as the idea that created it. The expedition-ready Flume capitalizes on all the sweetness of the Crestone, but does so in lightweight, 6000-series aluminum. Up mountains, down glaciers, and across deserts: the Flume is ready for action.

There are all kinds of alloy fat bikes on the market, but none with the Flume’s purebred heritage. The custom tubeset mates ideal, high-performance geometry with competition-ready spec. But if pedaling across our blue planet is more your speed, the Flume will speed you through.

The Flume is built on an alloy frame that draws on all of our experience in making fat bikes at a much lower price.

  • All aluminum frame with careful attention to finish details
  • Borealis unique geometry for the best ride experience
  • SRAM GX componets
  • Available in two colorways
  • Reduced stand over height
  • Carbon bar & seatpost
  • Carbon fork
  • GX
    MSRP:$2,449
    flume_gx

    As the alloy stablemate to the Crestone, the Flume GX represents what every other alloy fatbike aspires to be. SRAM drivetrain and brakes assures reliable, consistent performance, whether out for a quick spin during the winter solstice, or slogging the Iditarod Invitational. Hand-built wheels and an eye for detail always keeps you ahead of the pack on the Flume GX.

flume_gx

As the alloy stablemate to the Crestone, the Flume GX represents what every other alloy fatbike aspires to be. SRAM drivetrain and brakes assures reliable, consistent performance, whether out for a quick spin during the winter solstice, or slogging the Iditarod Invitational. Hand-built wheels and an eye for detail always keeps you ahead of the pack on the Flume GX.

    • Frame Borealis Flume lightweight 6066 alloy frame
    • Fork Borealis Carbon Rigid Fork
    • HeadsetCane Creek 40
    • Hubs Borealis. Front 15×150 Rear 12×197
    • Rims Turnagain FR80
    • Spokes Wheelsmith Black DB
    • NipplesWheelsmith Black Alloy
    • Rim StripsTurnagain RS80
    • Tires 26×4.0 Hüsker Dü 27tpi
    • Tubes Turnagain MagnumFAT
    • Bar Borealis Carbon 35 740mm
    • Stem Race Face Turbine 35 70mm
    • Post Borealis Carbon 31.6mm
    • Saddle Ergon SME30 EVO
    • Grips Ergon GA2
    • CranksetRace Face Aeffect Cinch 30t 175mm
    • Front Derailleur
    • Rear Derailleur SRAM GX 1×11
    • Chain KMC X11
    • CassetteSRAM XG-1150 10-42
    • Shifters SRAM GX 1×11
    • Brake Levers
    • Brakes SRAM DB5 w/Centerline 160/160mm rotors
    • DT/CS ProtectorLizard Skins

Stack and Reach are the fundamental fit elements, they are both measured relative to the bottom bracket. When choosing the Borealis that is right for you, it’s important to find a balance in these measurements to ensure the best performance.

geomtery_chart
S M L XL S M L XL
Effective Top Tube 23.78 in 24.02 in 24.8 in 25.59 in 604 mm 610 mm 630 mm 650 mm
Seat Tube Center to Top 15 in 17.01 in 19.06 in 21.02 in 381 mm 432 mm 484 mm 534 mm
Head Tube 4.13 in 4.72 in 5.31 in 5.91 in 105 mm 120 mm 135 mm 150 mm
Seat Tube Angle 73 deg 73 deg 73 deg 73 deg 73 deg 73 deg 73 deg 73 deg
Head Tube Angle 70 deg 70 deg 70 deg 70 deg 70 deg 70 deg 70 deg 70 deg
Standover Height Due to various rim and tire options stand over is not identified.
Chainstay 17.91 in 17.91 in 17.91 in 17.91 in 455 mm 455 mm 455 mm 455 mm
BB Drop 2.36 in 2.36 in 2.36 in 2.36 in 60 mm 60 mm 60 mm 60 mm
Reach 16.04 in 16.65 in 17.22 in 17.76 in 407.3 mm 423 mm 437.5 mm 451.2 mm
Stack 23.50 in 24.05 in 24.61 in 25.16 in 597 mm 610.9 mm 625 mm 639.1 mm

The Flume is built on an alloy frame that draws on all of our experience in making fat bikes at a much lower price.

  • All aluminum frame with careful attention to finish details
  • Borealis unique geometry for the best ride experience
  • SRAM GX componets
  • Available in two colorways
  • Reduced stand over height
  • Carbon bar
  • Carbon seatpost
  • Carbon fork