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 Monday 27th: 11am-4pm 

Borealis Flume NX

Borealis Flume NX
  • Color: Silver
  • Color: Seafoam
  • Color: Metallic Crimson Red
Color: Silver
Size: Select size
Please select options Unavailable


***PLEASE NOTE - The Borealis Flume bikes that we have in stock do not come equipped with the suspension fork displayed in the photo. The bikes we have in stock are equipped with rigid forks.***

With premium frame quality and only the best components, the Borealis Flume offers the best value on the market. This expedition-ready fatty mirrors the Crestone geometry, 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 and durability.


Standard features include: SRAM Eagle NX 12-Speed drivetrain, SRAM Level T brakes, rigid carbon fork, carbon handlebars, carbon seat post, durable Sun Ringle Mulefüt rims and your choice of tires.
Frame geometry provides responsive handling, offering maximum control for varying conditions in snow or sand.
Tire clearance up to 26x5” and 27.5x4.5”.
Compatibility for 100-120mm of suspension travel for increased comfort and control.
Lightweight, 6000-series aluminum frame comes with 2-3 bottle cage mounts, rear rack mounts on seat stays and Lizard Skin protectors on both the down tube and drive-side chain stay.

Rockshox Bluto Fork tire size limitations: 26x5” or 27.5x4”
Mastodon Pro EXT Fork tire size limitations: 26x5” or 27.5x4.5”
Borealis Rigid Carbon Fork tire size limitations: 26x5” or 27.5x4.5”
Dually 29x45 and 27.5x45 Rims – Max tire width: 3”
All rims 65mm to 85mm wide are compatible with tire widths of 3.8” to 5”
HED Carbon 100mm Rims – Max tire width of 4.8”


Frame Borealis Alloy
Fork Borealis Rigid Fork
Headset Borealis
Rims/Wheels Sun Ringle Mulefüt
Hubs Borealis: Front 15×150 Rear 12×197
Crankset SRAM Eagle NX
Chainwheel 30 Tooth
Bottom Bracket SRAM DUB 100mm
Chain KMC X12
Rear Derailleur SRAM EAGLE NX
Rear Cogs PG 1230 11-50
Handlebars Borealis Carbon Bar (35mm)
Tape/Grips Borealis
Stem Borealis 50mm or 70mm
Saddle Borealis
Seat Post Borealis Carbon Seatpost (31.6mm)

* Subject to change without notice.

Part Numbers

Option Store SKU
Silver / SM 15 BO21FNX15BZ
Silver / MD 17 BO21FNX17BZ
Silver / LG 19 BO21FNX19BZ
Silver / XL 21 BO21FNX21BZ
Seafoam / MD 17 BO22FNX17GN
Seafoam / LG 19 BO22FNX19GN
Seafoam / XL 21 BO22FNX21GN
Metallic Crimson Red / SM 15 BO22FNX15RD
Metallic Crimson Red / MD 17 BO22FNX17RD
Metallic Crimson Red / LG 19 BO22FNX19RD
Metallic Crimson Red / XL 21 BO22FNX21RD