Demos and Specials have varying levels of wear and tear. Most models have been lightly ridden and/or have blemishes.

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Since 2013, Borealis has specialized in lightweight carbon fiber fat bikes. 

    COMPATIBILITY

    • 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 4.6”

      ASSEMBLY

      If you choose "No Assembly" your bike will require complete assembly with an exception of the wheels. 

      If you choose "Assembled by Borealis", there is some assembly required upon receipt. Your bike will be completely assembled and tuned by Borealis, then partially disassembled for shipment. The remaining assembly will require installation of the rear derailleur, chain, fork, seat post, wheels, and handlebars. A multi-tool will be included with your order that has all tools necessary to assemble the bike, with the exception of a torque wrench. If you are not familiar with this level of assembly, we recommend having your local bike shop complete the assembly. Below is a video showing the remaining assembly once you receive the bike.

      Assembly Video 

       

      WHEELS & TIRES

      • All bikes come standard with tubes.
      • If you order rim tape with your Mulefut rims, we will tape the rims and install the tires with tubes.
      • HED Alloy and HED Carbon rims do not require rim tape for tubeless set up.
      • Tubes must be removed and tubeless valves installed for tubeless set up. We recommended to have this completed by a professional bicycle mechanic.

         

        SIZE CHART

        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.

         

         

        BUILD SPECS

        Eagle NX Eagle GX Eagle X01 Eagle XX
        Crankset SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX
        Crank Arms 175mm Alloy 175 Alloy 175mm Carbon 175mm Carbon
        Rear Derailleur RD ENX 1 x 12 RD EGX 1 x 12 RD EXO 1 x 12 RD EXX 1 x 12
        Chain KMC X12 KMC X12
        KMC X12
        SRAM XX
        Cassette PG 1230 11-50 XG 1275 10-52 XG 1295 10-52 XG 1299 10-50 Gold
        Shifter SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX1
        Brakes SRAM - Select SRAM - Select SRAM - Select SRAM - Select
        Chain Ring SRAM 30T X-Sync
        Frame Borealis Crestone Carbon
        Fork Borealis Carbon Rigid Fork
        Headset FSA
        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
        Bar RaceFace Next SL Carbon
        Stem Borealis 50mm or 70mm
        Post RaceFace Next SL Carbon 31.6
        Saddle Borealis
        Grips Borealis
        Bottom Bracket SRAM DUB 100mm
        DT/CS Protector Lizard Skins
        Weight See weight calculator for estimated weight.

         

        GEOMETRY CHART

        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.

          S M L XL
        EFFECTIVE TOP TUBE 585 mm 610 mm 630 mm 650 mm
        SEAT TUBE CENTER TO TOP 381 mm 432 mm 484 mm 534 mm
        HEAD TUBE 105 mm 120 mm 135 mm 150 mm
        SEAT TUBE ANGLE 73 deg 73 deg 73 deg 73 deg
        HEAD TUBE ANGLE 70 deg 70 deg 70 deg 70 deg
        STANDOVER HEIGHT Varies based on wheel and tire size
        CHAINSTAY 459 mm 459 mm 459 mm 459 mm
        BB DROP 60 mm 60 mm 60 mm 60 mm
        REACH 407 mm 423 mm 438 mm 451 mm
        STACK 597 mm 611 mm 625 mm 639 mm

         

        OWNER'S MANUAL

        Download Owner's Manual

         

         

        PO boxes not accepted. Shipping discounts or exclusions only apply within the lower 48 states of the US. Contact us if damage occurs during shipping. 

        Borealis offers a 30-day money-back guarantee. If you are unsatisfied with your purchase for any reason, you can cancel, exchange, or return your product for a full refund, minus any associated transaction fees and shipping costs. Customer is responsible for return shipping costs. Returned and exchanged items must be in sellable condition. Affirm transactions are subject to a 10% non-refundable transaction fee.

         

         

        $1,999.00
        Since 2013, Borealis has specialized in lightweight carbon fiber fat bikes. 

          COMPATIBILITY

          • 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 4.6”

            ASSEMBLY

            If you choose "No Assembly" your bike will require complete assembly with an exception of the wheels. 

            If you choose "Assembled by Borealis", there is some assembly required upon receipt. Your bike will be completely assembled and tuned by Borealis, then partially disassembled for shipment. The remaining assembly will require installation of the rear derailleur, chain, fork, seat post, wheels, and handlebars. A multi-tool will be included with your order that has all tools necessary to assemble the bike, with the exception of a torque wrench. If you are not familiar with this level of assembly, we recommend having your local bike shop complete the assembly. Below is a video showing the remaining assembly once you receive the bike.

            Assembly Video 

             

            WHEELS & TIRES

            • All bikes come standard with tubes.
            • If you order rim tape with your Mulefut rims, we will tape the rims and install the tires with tubes.
            • HED Alloy and HED Carbon rims do not require rim tape for tubeless set up.
            • Tubes must be removed and tubeless valves installed for tubeless set up. We recommended to have this completed by a professional bicycle mechanic.

               

              SIZE CHART

              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.

               

               

              BUILD SPECS

              Eagle NX Eagle GX Eagle X01 Eagle XX
              Crankset SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX
              Crank Arms 175mm Alloy 175 Alloy 175mm Carbon 175mm Carbon
              Rear Derailleur RD ENX 1 x 12 RD EGX 1 x 12 RD EXO 1 x 12 RD EXX 1 x 12
              Chain KMC X12 KMC X12
              KMC X12
              SRAM XX
              Cassette PG 1230 11-50 XG 1275 10-52 XG 1295 10-52 XG 1299 10-50 Gold
              Shifter SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX1
              Brakes SRAM - Select SRAM - Select SRAM - Select SRAM - Select
              Chain Ring SRAM 30T X-Sync
              Frame Borealis Crestone Carbon
              Fork Borealis Carbon Rigid Fork
              Headset FSA
              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
              Bar RaceFace Next SL Carbon
              Stem Borealis 50mm or 70mm
              Post RaceFace Next SL Carbon 31.6
              Saddle Borealis
              Grips Borealis
              Bottom Bracket SRAM DUB 100mm
              DT/CS Protector Lizard Skins
              Weight See weight calculator for estimated weight.

               

              GEOMETRY CHART

              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.

                S M L XL
              EFFECTIVE TOP TUBE 585 mm 610 mm 630 mm 650 mm
              SEAT TUBE CENTER TO TOP 381 mm 432 mm 484 mm 534 mm
              HEAD TUBE 105 mm 120 mm 135 mm 150 mm
              SEAT TUBE ANGLE 73 deg 73 deg 73 deg 73 deg
              HEAD TUBE ANGLE 70 deg 70 deg 70 deg 70 deg
              STANDOVER HEIGHT Varies based on wheel and tire size
              CHAINSTAY 459 mm 459 mm 459 mm 459 mm
              BB DROP 60 mm 60 mm 60 mm 60 mm
              REACH 407 mm 423 mm 438 mm 451 mm
              STACK 597 mm 611 mm 625 mm 639 mm

               

              OWNER'S MANUAL

              Download Owner's Manual

               

               

              PO boxes not accepted. Shipping discounts or exclusions only apply within the lower 48 states of the US. Contact us if damage occurs during shipping. 

              Borealis offers a 30-day money-back guarantee. If you are unsatisfied with your purchase for any reason, you can cancel, exchange, or return your product for a full refund, minus any associated transaction fees and shipping costs. Customer is responsible for return shipping costs. Returned and exchanged items must be in sellable condition. Affirm transactions are subject to a 10% non-refundable transaction fee.

               

               

              $1,999.00

              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.

              HIGHLIGHTS

              • 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.

                COMPATIBILITY

                • 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”

                   

                  ASSEMBLY

                  If you choose "No Assembly" your bike will require complete assembly with an exception of the wheels. 

                  If you choose "Assembled by Borealis", there is some assembly required upon receipt. Your bike will be completely assembled and tuned by Borealis, then partially disassembled for shipment. The remaining assembly will require installation of the rear derailleur, chain, fork, seat post, wheels, and handlebars. A multi-tool will be included with your order that has all tools necessary to assemble the bike, with the exception of a torque wrench. If you are not familiar with this level of assembly, we recommend having your local bike shop complete the assembly. Below is a video showing the remaining assembly once you receive the bike. 

                  Assembly Video

                  WHEELS & TIRES

                  • All bikes come standard with tubes.
                  • If you order rim tape with your Mulefut rims, we will tape the rims and install the tires with tubes.
                  • HED Alloy and HED Carbon rims do not require rim tape for tubeless set up.
                  • Tubes must be removed and tubeless valves installed for tubeless set up. We recommended to have this completed by a professional bicycle mechanic.

                  BUILD SPECS

                  Eagle NX Eagle GX Eagle X01 Eagle XX1
                  Crankset SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX1
                  Crank Arms 175mm Alloy 175 Alloy 175mm Carbon 175mm Carbon
                  Rear Derailleur RD ENX 1 x 12 RD EGX 1 x 12 RD EXO 1 x 12 RD EXX 1 x 12
                  Chain KMC X12 KMC X12
                  KMC X12
                  SRAM XX1
                  Cassette PG 1230 11-50 XG 1275 10-52 XG 1295 10-52 XG 1299 10-50 Gold
                  Shifters SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX1
                  Brakes SRAM - Select SRAM - Select SRAM - Select SRAM - Select
                  Chain Ring SRAM 30T X-Sync
                  Frame Borealis Flume Alloy
                  Fork Borealis Carbon Rigid Fork
                  Headset FSA
                  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
                  Bar RaceFace Next SL Carbon
                  Stem Borealis 50mm or 70mm
                  Post RaceFace Next SL Carbon 31.6
                  Saddle Borealis
                  Grips Borealis
                  Bottom Bracket SRAM DUB 100mm
                  DT/CS Protector Lizard Skins
                  Weight See weight calculator for estimated weight.

                   

                   

                   

                  SIZE CHART

                  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.

                   

                   

                  GEOMETRY CHART

                  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.

                    S M L XL
                  EFFECTIVE TOP TUBE 585 mm 610 mm 630 mm 650 mm
                  SEAT TUBE CENTER TO TOP 381 mm 432 mm 484 mm 534 mm
                  HEAD TUBE 105 mm 120 mm 135 mm 150 mm
                  SEAT TUBE ANGLE 73 deg 73 deg 73 deg 73 deg
                  HEAD TUBE ANGLE 70 deg 70 deg 70 deg 70 deg
                  STANDOVER HEIGHT Varies based on wheel and tire size
                  CHAINSTAY 455 mm 455 mm 455 mm 455 mm
                  BB DROP 60 mm 60 mm 60 mm 60 mm
                  REACH 407 mm 423 mm 438 mm 451 mm
                  STACK 597 mm 611 mm 625 mm 639 mm

                  PO boxes not accepted. Shipping discounts or exclusions only apply within the lower 48 states of the US. Contact us if damage occurs during shipping. 

                  Borealis offers a 30-day money-back guarantee. If you are unsatisfied with your purchase for any reason, you can cancel, exchange, or return your product for a full refund, minus any associated transaction fees and shipping costs. Customer is responsible for return shipping costs. Returned and exchanged items must be in sellable condition. Affirm transactions are subject to a 10% non-refundable transaction fee.

                   

                  $1,499.00

                  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.

                  HIGHLIGHTS

                  • 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.

                    COMPATIBILITY

                    • 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”

                       

                      ASSEMBLY

                      If you choose "No Assembly" your bike will require complete assembly with an exception of the wheels. 

                      If you choose "Assembled by Borealis", there is some assembly required upon receipt. Your bike will be completely assembled and tuned by Borealis, then partially disassembled for shipment. The remaining assembly will require installation of the rear derailleur, chain, fork, seat post, wheels, and handlebars. A multi-tool will be included with your order that has all tools necessary to assemble the bike, with the exception of a torque wrench. If you are not familiar with this level of assembly, we recommend having your local bike shop complete the assembly. Below is a video showing the remaining assembly once you receive the bike. 

                      Assembly Video

                      WHEELS & TIRES

                      • All bikes come standard with tubes.
                      • If you order rim tape with your Mulefut rims, we will tape the rims and install the tires with tubes.
                      • HED Alloy and HED Carbon rims do not require rim tape for tubeless set up.
                      • Tubes must be removed and tubeless valves installed for tubeless set up. We recommended to have this completed by a professional bicycle mechanic.

                      BUILD SPECS

                      Eagle NX Eagle GX Eagle X01 Eagle XX1
                      Crankset SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX1
                      Crank Arms 175mm Alloy 175 Alloy 175mm Carbon 175mm Carbon
                      Rear Derailleur RD ENX 1 x 12 RD EGX 1 x 12 RD EXO 1 x 12 RD EXX 1 x 12
                      Chain KMC X12 KMC X12
                      KMC X12
                      SRAM XX1
                      Cassette PG 1230 11-50 XG 1275 10-52 XG 1295 10-52 XG 1299 10-50 Gold
                      Shifters SRAM Eagle NX SRAM Eagle GX SRAM Eagle X01 SRAM Eagle XX1
                      Brakes SRAM - Select SRAM - Select SRAM - Select SRAM - Select
                      Chain Ring SRAM 30T X-Sync
                      Frame Borealis Flume Alloy
                      Fork Borealis Carbon Rigid Fork
                      Headset FSA
                      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
                      Bar RaceFace Next SL Carbon
                      Stem Borealis 50mm or 70mm
                      Post RaceFace Next SL Carbon 31.6
                      Saddle Borealis
                      Grips Borealis
                      Bottom Bracket SRAM DUB 100mm
                      DT/CS Protector Lizard Skins
                      Weight See weight calculator for estimated weight.

                       

                       

                       

                      SIZE CHART

                      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.

                       

                       

                      GEOMETRY CHART

                      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.

                        S M L XL
                      EFFECTIVE TOP TUBE 585 mm 610 mm 630 mm 650 mm
                      SEAT TUBE CENTER TO TOP 381 mm 432 mm 484 mm 534 mm
                      HEAD TUBE 105 mm 120 mm 135 mm 150 mm
                      SEAT TUBE ANGLE 73 deg 73 deg 73 deg 73 deg
                      HEAD TUBE ANGLE 70 deg 70 deg 70 deg 70 deg
                      STANDOVER HEIGHT Varies based on wheel and tire size
                      CHAINSTAY 455 mm 455 mm 455 mm 455 mm
                      BB DROP 60 mm 60 mm 60 mm 60 mm
                      REACH 407 mm 423 mm 438 mm 451 mm
                      STACK 597 mm 611 mm 625 mm 639 mm

                      PO boxes not accepted. Shipping discounts or exclusions only apply within the lower 48 states of the US. Contact us if damage occurs during shipping. 

                      Borealis offers a 30-day money-back guarantee. If you are unsatisfied with your purchase for any reason, you can cancel, exchange, or return your product for a full refund, minus any associated transaction fees and shipping costs. Customer is responsible for return shipping costs. Returned and exchanged items must be in sellable condition. Affirm transactions are subject to a 10% non-refundable transaction fee.

                       

                      $1,499.00