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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.
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
| Frame | Flume (Aluminum) | |||
| Fork | Borealis Carbon Rigid Fork Standard Option | |||
| Bottom Bracket | SRAM DUB 100mm | |||
| Crankset | SRAM Eagle NX Alloy 175mm w/ SRAM X-SYNC 30T | SRAM Eagle GX Alloy 175mm w/ SRAM X-SYNC 30T | SRAM Eagle X0 Carbon 175mm w/ SRAM X-SYNC 30T | SRAM Eagle XX Carbon 175mm w/ SRAM X-SYNC 30T |
| Rear Derailleur | SRAM Eagle NX 12 Speed | SRAM Eagle GX 12 Speed | SRAM Eagle X0 12 Speed | SRAM Eagle XX 12 Speed |
| Chain | Eagle GX | Eagle GX | Eagle GX | Eagle XX Gold |
| Cassette | PG 1230 11-50 | XG 1275 10-52 | XG 1295 10-52 | XG 1299 10-52 |
| Shifter | SRAM Eagle NX | SRAM Eagle GX | SRAM Eagle GX | SRAM Eagle GX |
| Brakes | SRAM Level T 2-piston OR SRAM G2 RS 4-Piston Hydraulic | |||
| Rotors | SRAM Centerline 160mm | |||
| Headset | FSA | |||
| Hubs | Borealis GEN 4 Black 15x150 Front / 12x197 Rear | |||
| Rims | Sun Ringle Mulefut V2 26x80 or 27.5x65 | |||
| Spokes | Borealis Straight Gauge | |||
| Nipples | Borealis Silver Brass | |||
| Tires | Your Choice | |||
| Bar | Borealis Carbon 35x760mm | |||
| Stem | Borealis 50mm | |||
| Post | Borealis Carbon 31.6x400mm | |||
| Saddle | Borealis | |||
| Grips | Ergon GP10 | |||
| 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
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.
$2,719.00
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.
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
| Frame | Flume (Aluminum) | |||
| Fork | Borealis Carbon Rigid Fork Standard Option | |||
| Bottom Bracket | SRAM DUB 100mm | |||
| Crankset | SRAM Eagle NX Alloy 175mm w/ SRAM X-SYNC 30T | SRAM Eagle GX Alloy 175mm w/ SRAM X-SYNC 30T | SRAM Eagle X0 Carbon 175mm w/ SRAM X-SYNC 30T | SRAM Eagle XX Carbon 175mm w/ SRAM X-SYNC 30T |
| Rear Derailleur | SRAM Eagle NX 12 Speed | SRAM Eagle GX 12 Speed | SRAM Eagle X0 12 Speed | SRAM Eagle XX 12 Speed |
| Chain | Eagle GX | Eagle GX | Eagle GX | Eagle XX Gold |
| Cassette | PG 1230 11-50 | XG 1275 10-52 | XG 1295 10-52 | XG 1299 10-52 |
| Shifter | SRAM Eagle NX | SRAM Eagle GX | SRAM Eagle GX | SRAM Eagle GX |
| Brakes | SRAM Level T 2-piston OR SRAM G2 RS 4-Piston Hydraulic | |||
| Rotors | SRAM Centerline 160mm | |||
| Headset | FSA | |||
| Hubs | Borealis GEN 4 Black 15x150 Front / 12x197 Rear | |||
| Rims | Sun Ringle Mulefut V2 26x80 or 27.5x65 | |||
| Spokes | Borealis Straight Gauge | |||
| Nipples | Borealis Silver Brass | |||
| Tires | Your Choice | |||
| Bar | Borealis Carbon 35x760mm | |||
| Stem | Borealis 50mm | |||
| Post | Borealis Carbon 31.6x400mm | |||
| Saddle | Borealis | |||
| Grips | Ergon GP10 | |||
| 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
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.
$2,719.00
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.
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 | |
| Frame | Flume (Aluminum) | Flume (Aluminum) |
| Fork | Borealis Carbon Rigid Fork Standard Option | |
| Bottom Bracket | SRAM DUB 100mm | |
| Crankset | SRAM Eagle NX Alloy 175mm w/ SRAM X-SYNC 30T | SRAM Eagle GX Alloy 175mm w/ SRAM X-SYNC 30T |
| Rear Derailleur | SRAM Eagle NX 12 Speed | SRAM Eagle GX 12 Speed |
| Chain | Eagle GX | Eagle GX |
| Cassette | PG 1230 11-50 | XG 1275 10-52 |
| Shifter | SRAM Eagle NX | SRAM Eagle GX |
| Brakes | SRAM Level T 2-Piston Hydraulic | |
| Rotors | SRAM Centerline 160mm | |
| Headset | FSA | |
| Hubs | Borealis GEN 4 Black 15x150 Front / 12x197 Rear | |
| Rims | Sun Ringle Mulefut V2 26x80 or 27.5x65 | |
| Spokes | Borealis Straight Gauge | |
| Nipples | Borealis Silver Brass | |
| Tires | Your Choice | |
| Bar | Borealis Carbon 35x760mm | |
| Stem | Borealis 50mm | |
| Post | Borealis Carbon 31.6x400mm | |
| Saddle | Borealis | |
| Grips | Ergon GA20 | |
| 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.
$2,039.00
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.
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 | |
| Frame | Flume (Aluminum) | Flume (Aluminum) |
| Fork | Borealis Carbon Rigid Fork Standard Option | |
| Bottom Bracket | SRAM DUB 100mm | |
| Crankset | SRAM Eagle NX Alloy 175mm w/ SRAM X-SYNC 30T | SRAM Eagle GX Alloy 175mm w/ SRAM X-SYNC 30T |
| Rear Derailleur | SRAM Eagle NX 12 Speed | SRAM Eagle GX 12 Speed |
| Chain | Eagle GX | Eagle GX |
| Cassette | PG 1230 11-50 | XG 1275 10-52 |
| Shifter | SRAM Eagle NX | SRAM Eagle GX |
| Brakes | SRAM Level T 2-Piston Hydraulic | |
| Rotors | SRAM Centerline 160mm | |
| Headset | FSA | |
| Hubs | Borealis GEN 4 Black 15x150 Front / 12x197 Rear | |
| Rims | Sun Ringle Mulefut V2 26x80 or 27.5x65 | |
| Spokes | Borealis Straight Gauge | |
| Nipples | Borealis Silver Brass | |
| Tires | Your Choice | |
| Bar | Borealis Carbon 35x760mm | |
| Stem | Borealis 50mm | |
| Post | Borealis Carbon 31.6x400mm | |
| Saddle | Borealis | |
| Grips | Ergon GA20 | |
| 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.
$2,039.00
Introducing the all-new Keystone Electric Fat Tire Bike. Since 2013, Borealis has specialized in lightweight, high end fat bikes. The Keystone is our first ever Class I electric bike. The frame geometry is optimized for riding just about anything with clearance for up to 5” wide tires. Paired with the most technically advanced components in the industry, the Keystone sets the standard for premium quality Electric fat bikes.
HIGHLIGHTS
- Color: Gunmetal Grey with Cobalt Blue Graphics
- Weight: 56 lbs. as shown.
- Standard features include Shimano EP8 Drive Unit, Shimano 630Wh Battery, SRAM G2 RS brakes, Mastodon Pro EXT 120mm suspension fork, carbon handlebars, dropper 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”.
- Lightweight, 6000 series aluminum frame comes with internally routed cables, 1-2 bottle cage mounts and lizard skin protection.
- Keystone Frames are backed by our LIMITED LIFETIME WARRANTY.
ASSEMBLY
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 kit will be included with your order that has all the necessary tools assemble your bike, including a multi-tool, torque wrench, and shock pump. If you are not familiar with this level of assembly, we recommend having your local bike shop complete the assembly.
Stay tuned for our step-by-step assembly video.
WHEELS AND 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.
- 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
BUILD SPECS
| Frame | Borealis Keystone Aluminum 15", 17", 19", 21" |
| Drive Unit | Shimano DU-EP800 |
| Battery | Shimano BT-E8036 (630Wh) |
| Display | Shimano SC-EM800 |
| Assist Switch | Shimano SW-EM800L |
| Speed Sensor | Shimano EWSS300L540A |
| Fork | Manitou Mastodon PRO EXT 120mm, 51mm offset |
| Headset | FSA w/ Star Nut |
| Stem | Borealis 50mm |
| Handlebar | Borealis Carbon |
| Grips | Ergon GP1 |
| Saddle | WTB Volt Medium Steel |
| Seat Collar | Borealis Bolt-On |
| Seatpost | KS Lev Integra 125mm (SM, MD) / 150mm (LG, XL) |
| Brakes | SRAM G2 RS |
| Rotors | SRAM HS2 200mm front / 180mm rear |
| Shifter | SRAM AXS Pod Contoller Right Bridge w/ MMX Clamp for GX Eagle Transmission |
| Derailleur | SRAM GX Eagle Transmission Derailleur |
| Cassette | SRAM GX Eagle Transmission Cassette 10-52T |
| Chain | SRAM GX Eagle Transmission Flattop Chain |
| Crank Arms | Samox 170mm |
| Chainring Mount | Samox 104 BCD for 75mm chainline |
| Chainring | SRAM Eagle Transmission E-Bike MTB Chainring 104 BCD 36T Steel |
| Rims | Your choice of SunRingle Mulefüt SL - 26x80, 27.5x80, or 27.5x65 |
| Spokes | Straight Gauge 2.0 Black |
| Hubs | Borealis Gen 4 15x150 / 12x197 |
| Tires | Your choice. All tire options are listed online. |
| Included | Shimano ECE80042 Battery Charger, AXS Power Pack, Kickstand, UDH Hanger, Key for battery release, Borealis Rear Thru Axle, Remote Battery Charging Adapter |
| Weight | Size Medium w/ Mulefut 27.5x80 & Terrene Yippee Ki Yay 4.3" Tires: 56 lbs. |
FRAME SPECS
| Wheel / Tire Size | 26 x 3.8–5.0" on up to a 100mm rim / 27.5 x 2.8-4.5 on up to a 82mm rim / 29 x 2.25–3.0 |
| Susp Fork Travel | 120mm |
| Fork Offset | 51mm |
| Headset-Upper | IS41 |
| Headset-Lower | IS52 |
| Seatpost | ø31.6mm |
| Seat Collar | ø34.9mm |
| Dropper Compatible | Internal - 125mm for SM & MD / 150mm for LG & XL |
| Front Derailleur Type | Not Compatible |
| Bottom Bracket | Shimano EP8 |
| Crankset (Max Ring) | Chainline 75mm / 1x (38t) |
| Rear Brake (Rotor) | 74mm post (160–180mm) |
| Rear Spacing | 197 x 12mm thru-axle |
| Rear Axle | ø12 x 222L, TP= 1.0, TL = 16 |
| Derailleur Hanger | SRAM UDH |
| Bottle Mount | Small & Medium: 1 (downtube) / Large & XL: 2 (downtube & seatube) |
| Rear Rack Reccomendation | Old Man Mountain Divide Fat |
| Rear Rack Mounts, Upper | Yes |
| Axle to Crown | 531mm |
| Steerer Tube Size | 28.6mm |
| Steerer Style | Tapered |
| Crown Seat Diameter | 40mm |
GEOMETRY CHART
| Small 15" | Medium 17" | Large 19" | X-Large 21" | |
| Effective Top Tube | 630 | 645 | 660 | 665 |
| Seat Tube Center to Top | 381 | 432 | 482 | 533 |
| Head Tube Length | 160 | 160 | 175 | 190 |
| Head Tube Angle | 69° | 69° | 69° | 69° |
| Seat Tube Angle | 73° | 73° | 73° | 73° |
| Chainstay Length | 480 | 480 | 480 | 480 |
| BB Drop | 60 | 60 | 60 | 60 |
| Reach | 420 | 435 | 445 | 446 |
| Stack | 688 | 688 | 702 | 716 |
| Standover Height | varies based on wheel and tire size | |||
| Wheelbase | 1187 | 1207 | 1223 | 1229 |
| Fork Offset | 51 | 51 | 51 | 51 |
FAQ:
| Can I use the Keystone in cold temperatures? | It is okay to use your Keystone in the operating temperature range, suggest by Shimano: -10 - 50°C |
| How do I remove the battery? | Each Keystone will come with a set of keys. Make sure to save your spare key and safe location. Insert the key fully into the lock cylinder on the non drive side of the downtube until it stops. Rotate the key clockwise until the battery drops from the downtube providing access to the latch release mechanism. Use your index finger to gently depress the spring which will fully release the battery. Use caution to support the battery when removing it so it does not fall to the ground. |
| How can I file a warranty claim for the drive unit and other electronic components? | Contact an authorized Shimano STEPS dealer. |
| Can I change my motor/power settings? | Yes, you can customize your motor settings via the app as well as update the firmware. You'll need to download the Shimano E-tube mobile app. |
| Can I change the max speed? | No. Depending on where you've purchased your Keystone it will either have a max assist speed of 20mph or 25km/h. This setting cannot be modified by the user or a dealer. |
| Can I purchase an extra battery? | Yes, you can purchase a spare battery kit with a spare downtube cover directly from Borealis. Spare battery kits may not be available in all markets. You can also purchase a spare battery from Shimano, but it will not include a battery cover. |
| Can I ride the Keystone without the battery? | No. This will void your warranty with Shimano and cause damage to the motor system. |
| Do I need to update the firmware / software? | Firmware can be updated via the Shimano E-tube mobile app. |
| How do I use walk mode? | Hold the upper button (down assistance level) for 1 second until the display turns blue and displays WALK mode. Press and hold the same button to power the rear wheel. |
| How long does it take to charge the Shimano 630Wh Battery? | With the included EC-E8004 charger, the battery can fully charge in 6 hours. |
| How long will my battery last? | The remaining battery capacity is affected by temperature and cycle count. Generally, it decreases approximately 5% a year. This means roughly 95% capacity remains after 1 year, and 90% after 2 years. |
| How should I store my bike and or battery? | Charge your battery to approximately 70% before storing for long periods of time. Store in a cool, indoor location with a stable temperature between approximately 10 - 20 C / 50 - 70 F. No direct exposure to sunlight or rain. |
| Are the electronic components waterproof? | Yes, the STEPS system is waterproof as long as all components of the system, including the battery and battery cover, are installed correctly. We recommend not using a high-pressure washer to clean your Repeater, but riding in the rain and regular cleaning are okay. |
| My bike won't turn on, what do I do? | First, make sure all cables are plugged in, if they are then try removing and reinstalling the battery. If it still won't turn on try charging your bike for a few hours. If your bike is too hot or too cold, it might not turn on. If your bike still does not turn on, contact a Transition or Shimano dealer for support. |
| Should I only charge my battery when it's completely drained? | No, simply charge the battery any time you need it, frequent charges actually help battery longevity. Avoid letting the battery discharge completely. Charge to 70% before storing for long periods. |
| What are the different error codes and what do they mean? | Whenever you encounter an error code, first cycle the power off and then back on. If the code persists, remove the battery and then reinstall, which will hard reset the system. If neither of these steps resolves the issue, please reference the Shimano error code list. If you cannot resolve your error code via your Etube mobile app please visit your nearest Shimano STEPS dealer or contact Shimano STEPS customer support. |
| What is the range and how can I maximize it? | There are many factors that affect battery range, such as, how much effort the rider is providing, the gradient of terrain, ambient temperature, and rider weight. The best way to maximize your range it to spend more time in Eco and Trail modes, and minimize the amount of time spent in Boost mode. |
| What is the widest tire the Keystone can fit? | 26x5.0" or 27.5x4.5" |
| What kind of maintenance is needed on the drive unit and how often? | The drive unit is sealed and cannot be serviced. If there are any issues with the drive unit, it will need to be removed and sent back to Shimano for service or replacement. The drive unit along with the battery is designed to last over 1000 charge cycles. Assuming you're getting 30 miles (48Km) per charge, the drive unit should last 30,000 miles, or much longer than pretty much any other part on your bike. |
| Why does my bike stop giving assistance over a certain speed? | Depending on where you've purchased your Keystone it will either have a max assist speed of 20mph or 25km/h. This setting cannot be modified by the user or a dealer. |
| Will environmental temperature affect battery life? | The battery life will be shorter during cold temperatures, this is not a sign of a problem. |
| Will my bike be delivered with a charged battery? | Your Keystone was shipped in a "sleep" mode with the battery at approximately 30% charge. It is recommended to fully charge your battery before the first ride. |
$8,840.00
Introducing the all-new Keystone Electric Fat Tire Bike. Since 2013, Borealis has specialized in lightweight, high end fat bikes. The Keystone is our first ever Class I electric bike. The frame geometry is optimized for riding just about anything with clearance for up to 5” wide tires. Paired with the most technically advanced components in the industry, the Keystone sets the standard for premium quality Electric fat bikes.
HIGHLIGHTS
- Color: Gunmetal Grey with Cobalt Blue Graphics
- Weight: 56 lbs. as shown.
- Standard features include Shimano EP8 Drive Unit, Shimano 630Wh Battery, SRAM G2 RS brakes, Mastodon Pro EXT 120mm suspension fork, carbon handlebars, dropper 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”.
- Lightweight, 6000 series aluminum frame comes with internally routed cables, 1-2 bottle cage mounts and lizard skin protection.
- Keystone Frames are backed by our LIMITED LIFETIME WARRANTY.
ASSEMBLY
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 kit will be included with your order that has all the necessary tools assemble your bike, including a multi-tool, torque wrench, and shock pump. If you are not familiar with this level of assembly, we recommend having your local bike shop complete the assembly.
Stay tuned for our step-by-step assembly video.
WHEELS AND 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.
- 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
BUILD SPECS
| Frame | Borealis Keystone Aluminum 15", 17", 19", 21" |
| Drive Unit | Shimano DU-EP800 |
| Battery | Shimano BT-E8036 (630Wh) |
| Display | Shimano SC-EM800 |
| Assist Switch | Shimano SW-EM800L |
| Speed Sensor | Shimano EWSS300L540A |
| Fork | Manitou Mastodon PRO EXT 120mm, 51mm offset |
| Headset | FSA w/ Star Nut |
| Stem | Borealis 50mm |
| Handlebar | Borealis Carbon |
| Grips | Ergon GP1 |
| Saddle | WTB Volt Medium Steel |
| Seat Collar | Borealis Bolt-On |
| Seatpost | KS Lev Integra 125mm (SM, MD) / 150mm (LG, XL) |
| Brakes | SRAM G2 RS |
| Rotors | SRAM HS2 200mm front / 180mm rear |
| Shifter | SRAM AXS Pod Contoller Right Bridge w/ MMX Clamp for GX Eagle Transmission |
| Derailleur | SRAM GX Eagle Transmission Derailleur |
| Cassette | SRAM GX Eagle Transmission Cassette 10-52T |
| Chain | SRAM GX Eagle Transmission Flattop Chain |
| Crank Arms | Samox 170mm |
| Chainring Mount | Samox 104 BCD for 75mm chainline |
| Chainring | SRAM Eagle Transmission E-Bike MTB Chainring 104 BCD 36T Steel |
| Rims | Your choice of SunRingle Mulefüt SL - 26x80, 27.5x80, or 27.5x65 |
| Spokes | Straight Gauge 2.0 Black |
| Hubs | Borealis Gen 4 15x150 / 12x197 |
| Tires | Your choice. All tire options are listed online. |
| Included | Shimano ECE80042 Battery Charger, AXS Power Pack, Kickstand, UDH Hanger, Key for battery release, Borealis Rear Thru Axle, Remote Battery Charging Adapter |
| Weight | Size Medium w/ Mulefut 27.5x80 & Terrene Yippee Ki Yay 4.3" Tires: 56 lbs. |
FRAME SPECS
| Wheel / Tire Size | 26 x 3.8–5.0" on up to a 100mm rim / 27.5 x 2.8-4.5 on up to a 82mm rim / 29 x 2.25–3.0 |
| Susp Fork Travel | 120mm |
| Fork Offset | 51mm |
| Headset-Upper | IS41 |
| Headset-Lower | IS52 |
| Seatpost | ø31.6mm |
| Seat Collar | ø34.9mm |
| Dropper Compatible | Internal - 125mm for SM & MD / 150mm for LG & XL |
| Front Derailleur Type | Not Compatible |
| Bottom Bracket | Shimano EP8 |
| Crankset (Max Ring) | Chainline 75mm / 1x (38t) |
| Rear Brake (Rotor) | 74mm post (160–180mm) |
| Rear Spacing | 197 x 12mm thru-axle |
| Rear Axle | ø12 x 222L, TP= 1.0, TL = 16 |
| Derailleur Hanger | SRAM UDH |
| Bottle Mount | Small & Medium: 1 (downtube) / Large & XL: 2 (downtube & seatube) |
| Rear Rack Reccomendation | Old Man Mountain Divide Fat |
| Rear Rack Mounts, Upper | Yes |
| Axle to Crown | 531mm |
| Steerer Tube Size | 28.6mm |
| Steerer Style | Tapered |
| Crown Seat Diameter | 40mm |
GEOMETRY CHART
| Small 15" | Medium 17" | Large 19" | X-Large 21" | |
| Effective Top Tube | 630 | 645 | 660 | 665 |
| Seat Tube Center to Top | 381 | 432 | 482 | 533 |
| Head Tube Length | 160 | 160 | 175 | 190 |
| Head Tube Angle | 69° | 69° | 69° | 69° |
| Seat Tube Angle | 73° | 73° | 73° | 73° |
| Chainstay Length | 480 | 480 | 480 | 480 |
| BB Drop | 60 | 60 | 60 | 60 |
| Reach | 420 | 435 | 445 | 446 |
| Stack | 688 | 688 | 702 | 716 |
| Standover Height | varies based on wheel and tire size | |||
| Wheelbase | 1187 | 1207 | 1223 | 1229 |
| Fork Offset | 51 | 51 | 51 | 51 |
FAQ:
| Can I use the Keystone in cold temperatures? | It is okay to use your Keystone in the operating temperature range, suggest by Shimano: -10 - 50°C |
| How do I remove the battery? | Each Keystone will come with a set of keys. Make sure to save your spare key and safe location. Insert the key fully into the lock cylinder on the non drive side of the downtube until it stops. Rotate the key clockwise until the battery drops from the downtube providing access to the latch release mechanism. Use your index finger to gently depress the spring which will fully release the battery. Use caution to support the battery when removing it so it does not fall to the ground. |
| How can I file a warranty claim for the drive unit and other electronic components? | Contact an authorized Shimano STEPS dealer. |
| Can I change my motor/power settings? | Yes, you can customize your motor settings via the app as well as update the firmware. You'll need to download the Shimano E-tube mobile app. |
| Can I change the max speed? | No. Depending on where you've purchased your Keystone it will either have a max assist speed of 20mph or 25km/h. This setting cannot be modified by the user or a dealer. |
| Can I purchase an extra battery? | Yes, you can purchase a spare battery kit with a spare downtube cover directly from Borealis. Spare battery kits may not be available in all markets. You can also purchase a spare battery from Shimano, but it will not include a battery cover. |
| Can I ride the Keystone without the battery? | No. This will void your warranty with Shimano and cause damage to the motor system. |
| Do I need to update the firmware / software? | Firmware can be updated via the Shimano E-tube mobile app. |
| How do I use walk mode? | Hold the upper button (down assistance level) for 1 second until the display turns blue and displays WALK mode. Press and hold the same button to power the rear wheel. |
| How long does it take to charge the Shimano 630Wh Battery? | With the included EC-E8004 charger, the battery can fully charge in 6 hours. |
| How long will my battery last? | The remaining battery capacity is affected by temperature and cycle count. Generally, it decreases approximately 5% a year. This means roughly 95% capacity remains after 1 year, and 90% after 2 years. |
| How should I store my bike and or battery? | Charge your battery to approximately 70% before storing for long periods of time. Store in a cool, indoor location with a stable temperature between approximately 10 - 20 C / 50 - 70 F. No direct exposure to sunlight or rain. |
| Are the electronic components waterproof? | Yes, the STEPS system is waterproof as long as all components of the system, including the battery and battery cover, are installed correctly. We recommend not using a high-pressure washer to clean your Repeater, but riding in the rain and regular cleaning are okay. |
| My bike won't turn on, what do I do? | First, make sure all cables are plugged in, if they are then try removing and reinstalling the battery. If it still won't turn on try charging your bike for a few hours. If your bike is too hot or too cold, it might not turn on. If your bike still does not turn on, contact a Transition or Shimano dealer for support. |
| Should I only charge my battery when it's completely drained? | No, simply charge the battery any time you need it, frequent charges actually help battery longevity. Avoid letting the battery discharge completely. Charge to 70% before storing for long periods. |
| What are the different error codes and what do they mean? | Whenever you encounter an error code, first cycle the power off and then back on. If the code persists, remove the battery and then reinstall, which will hard reset the system. If neither of these steps resolves the issue, please reference the Shimano error code list. If you cannot resolve your error code via your Etube mobile app please visit your nearest Shimano STEPS dealer or contact Shimano STEPS customer support. |
| What is the range and how can I maximize it? | There are many factors that affect battery range, such as, how much effort the rider is providing, the gradient of terrain, ambient temperature, and rider weight. The best way to maximize your range it to spend more time in Eco and Trail modes, and minimize the amount of time spent in Boost mode. |
| What is the widest tire the Keystone can fit? | 26x5.0" or 27.5x4.5" |
| What kind of maintenance is needed on the drive unit and how often? | The drive unit is sealed and cannot be serviced. If there are any issues with the drive unit, it will need to be removed and sent back to Shimano for service or replacement. The drive unit along with the battery is designed to last over 1000 charge cycles. Assuming you're getting 30 miles (48Km) per charge, the drive unit should last 30,000 miles, or much longer than pretty much any other part on your bike. |
| Why does my bike stop giving assistance over a certain speed? | Depending on where you've purchased your Keystone it will either have a max assist speed of 20mph or 25km/h. This setting cannot be modified by the user or a dealer. |
| Will environmental temperature affect battery life? | The battery life will be shorter during cold temperatures, this is not a sign of a problem. |
| Will my bike be delivered with a charged battery? | Your Keystone was shipped in a "sleep" mode with the battery at approximately 30% charge. It is recommended to fully charge your battery before the first ride. |
$8,840.00
