13KGHT53 Borealis Flume Alloy SRAM Eagle 12 speed Borealis Bikes Canada

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Borealis Flume Alloy GX Eagle, M, Mastodon, Bronze, Ready to Ship, #37
Borealis Flume Alloy GX Eagle, M, Mastodon, Bronze, Ready to Ship, #37

Borealis Flume Alloy GX Eagle, M, Mastodon, Bronze, Ready to Ship, #37

Borealis Bikes Canada
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This listing is for a Medium Flume with SRAM GX Eagle's specs (299$ upgrade) as described below with Mulefut alloy 27.5x80mm wheelset. Mastodon Pro Extended is a 500$ upgrade. Shipping date is approximative.  You can select the tires only, no other changes permitted.


Enter into Borealis perfection without blowing your budget. The Flume Eagle 12 speed offers carbon bars, carbon seat post and a carbon fork. Utilizing SRAM Eagle 12 speed components and a solid wheelset, this ride will take you anywhere you want to go! This is the perfect Fat Bike for the budget conscious or “Gotta Try It” individual.


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 Eagle 12 speed components
  • Reduced stand over height
  • Carbon bar & seatpost
  • Carbon fork


  Eagle GX Eagle NX
Frame Lightweight 6066 Alloy Lightweight 6066 Alloy
Fork Mastodon Pro EXT 120mm Mastodon Pro EXT 120mm
Headset Borealis Borealis
Hubs Borealis: Front 15x150 Rear 12x197, 12x179 Borealis: Front 15x150 Rear 12x197, 12x180
Rims Mulefut Alloy 27.5x80mm Mulefut Alloy 27.5x80mm
Spokes Wheelsmith Black Wheelsmith Black
Nipples Wheelsmith Silver Brass Wheelsmith Silver Brass
Tires Multiple Options Multiple Options
Bar Borealis Carbon 35mm Borealis Carbon 35mm
Stem Borealis 50 or 70mm Borealis 50 or 70mm
Post Borealis Carbon Seatpost 31.6mm Borealis Carbon Seatpost 31.6mm
Saddle Borealis Borealis
Grips Ergon GA2 or GP1 L (Paddle) Ergon GA2 or GP1 L (Paddle)
Crankset SRAM Eagle Alloy GX w/30T Chain Ring SRAM Eagle NX
Rear Derailleur SRAM Eagle GX1 12 Speed SRAM Eagle NX 12 Speed
Chain KMC 12 Speed KMC 12 Speed
Cassette SRAM Eagle XG-1275 10-50 SRAM PG 1230 10-50
Shifters SRAM Eagle GX 12 Speed SRAM Eagle NX 12 Speed
Brakes SRAM Level T w/ Centerline 160/160 SRAM Level T w/Centerline 160/160mm Rotors
DT/CS Protector Lizard Skins Lizard Skins



Geometry & Sizing

Borealis offers four frame designs with unique fit and geometry to suit your every Fat Bike need. Begin by taking a rough size approximation on the chart below that is based on height, then select the corresponding bike with your fit needs by using the geometry chart further below. We recommend a similar fit to you mountain bike, so grab a measuring tape and dial it in.


Based on our research, riders at the heights below will usually take the corresponding frame size. If you’re at a transitional height that spans two sizes, look at the geometry chart to get the Stack and Reach you like based on other bikes you are comfortable on.



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.

All sales are final, no returns. All frames are covered by a 5 year warranty and crash replacement program.

Please take note of the following: Shipping and handling charges do NOT apply to the NWT, Yukon, Nunavut and Labrador, remote areas or areas that do not have year round road access. For these area, please contact us. Photos DO NOT reflect actual build, please refer to specifications located below for more information.  Some items may be changed to same quality components depending on availability. Assembled by Borealis (85% build), some assembly required upon receipt. No assembly, requires complete build.

SAFETY NOTICE:  Please note our bikes are designed for off road use and do not include safety reflectors which may be required for on road riding in your location.  If you require legal safety reflectors please contact your local bike dealer.

All directions of the Manufacturer or Retailer must be followed when using any product purchased through Borealis Bikes Canada. Specifically, bikes must be assembled by a qualified bike mechanic to ensure correct assembly. Borealis Bikes Canada will not be responsible for damage or injury caused by improper assembly of products purchased through our website or other website (Amazon, Craig's List, e-Bay, Google, BikeExchange, etc.) or if directions and instructions for proper use are not followed. You may not qualify for any applicable Manufacturer or Retailer warranty if you do not follow their policies for assembly and use. Please consult the Manufacturer or Retailer’s policies prior to assembly and use of your product.

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
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