Borealis Flume Aluminum Fat Tire Bicycle

EXPEDITION-READY FAT BIKE

BUILT FOR ADVENTURE

The Borealis Flume is an expedition-ready fat bike built for tackling any adventure. Its lightweight 6000-series aluminum frame pairs with a high-performance SRAM GX Eagle 12-speed drivetrain and SRAM Level T brakes for precise control on rugged terrain. Carbon handlebars and a carbon seat post add strength without the weight, while the robust Sun Ringle Mulefüt rims ensure durability and agility. With tire clearance up to 26×5” and 27.5×4.5” and compatibility with 100-120mm of suspension travel, this fat bike is primed for mountains, glaciers, and deserts alike. It also includes 2-3 bottle cage mounts, rear rack mounts, and Lizard Skin protectors to make your next adventure seamless.

Contact us today to build your custom Flume! 2025 Season pricing is now available, offering some of the best prices on the Borealis line!

Specifications:

Drivetrain:

• Eagle NX: SRAM Eagle NX Crankset, 175mm Alloy Crank Arms, RD ENX 1 x 12 Rear Derailleur, KMC X12 Chain, PG 1230 11-50 Cassette, SRAM Eagle NX Shifters (Currently Unavailable)
• Eagle GX: SRAM Eagle GX Crankset, 175 Alloy Crank Arms, RD EGX 1 x 12 Rear Derailleur, KMC X12 Chain, XG 1275 10-50 Cassette, SRAM Eagle GX Shifters
• Brakes: SRAM – Select
• Chain Ring: SRAM 30T X-Sync

Frame & Fork:

• Frame: Borealis Crestone Carbon
• Fork: Borealis Carbon Rigid Fork

Wheels:

• Hubs: Borealis (Front 15×150, Rear 12×197)
• Rims: 26″ or 27.5″ Sun Ringle Mulefut V2
• Spokes: Borealis Straight Gauge
• Nipples: Borealis Silver Brass
• Tires: Your Choice

Cockpit:

• Handlebar: Borealis Carbon Bar (35mm)
• Stem: Borealis 50mm or 70mm
• Seatpost: Borealis Carbon Seatpost (31.6mm)
• Saddle: Borealis
• Grips: Borealis

Additional Features:

• Bottom Bracket: SRAM DUB 100mm
• DT/CS Protector: Lizard Skins
• Accessories: 2-3 Bottle Cage Mounts, Rear Rack Mounts