13KGHT53 Keystone E-Fatbike, SRAM GX AXS Wireless, Mastodon Pro & Dropper Post – Borealis Bikes Canada

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Keystone E-Fatbike, SRAM GX AXS Wireless, Mastodon Pro & Dropper Post
Keystone E-Fatbike, SRAM GX AXS Wireless, Mastodon Pro & Dropper Post
Keystone E-Fatbike, SRAM GX AXS Wireless, Mastodon Pro & Dropper Post

Keystone E-Fatbike, SRAM GX AXS Wireless, Mastodon Pro & Dropper Post

Borealis Bikes Canada
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Introducing the all-new Keystone. 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. 


  • 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.


Some assembly required upon receipt. Keystones will be completely assembled and tuned by Borealis. Bicycles will be 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. 

Stay tuned for our step-by-step assembly video. 


  • 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.



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.


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



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


- What regular maintenance is necessary on the Keystone Electric Bike?

Before each ride, check threaded fasteners for appropriate torque before every ride. Keeping your Ebike clean and properly lubricated will always increase lifespan of the individual components. Reference individual component owner's manual for specific information on maintenance.

- Can I change my Shimano Ebike motor/power settings?

Yes, you can customize your Shimano 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 of my Ebike?

No. Depending on where you've purchased your Keystone Fat EBike 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 Shimano Ebike battery?

Yes, you can purchase a spare Shimano battery kit with a spare downtube cover directly from Borealis. Availability will vary. 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. Contact sales@fatbike.com about purchasing an extra battery.

- Can I ride the Keystone Fat Ebike without the Shimano battery installed?

No. This will void your warranty with Shimano and cause damage to the motor system.

- Do I need to update the Shimano firmware/software?

Firmware can be updated via the Shimano E-tube mobile app.

- How can I file a warranty claim for the Shimano drive unit and other electronic components?

Contact an authorized Shimano STEPS dealer.

- How do I remove the Shimano battery?

Each Keystone Fat EBike 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 do I use walk mode on the Keystone Fat Ebike?

On the Shimano Assist Switch, hold the upper button (down assistance level) for 1 second until the Shimano 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 Shimano charger, a completely dead battery would charge to 100% in around 6 hours.

- How long will my Shimano battery last?

The remaining Shimano 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 Ebike battery and / or Shimano battery?

Charge your Shimano 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 Shimano electronic components waterproof on my Ebike?

Yes, the Shimano 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 Keystone, but riding in the rain and regular cleaning are okay.

- My Ebike 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 Borealis or Shimano dealer for support.

- Should I only charge my Shimano battery when it is completely drained?

No, simply charge the Shimano 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 Shimano error codes and what do they mean?

Whenever you encounter a Shimano error code on your display, 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 Keystone Fat Tire Ebike 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 Fat Tire Ebike can fit?

26x5.0" or 27.5x4.5"

- What kind of maintenance is needed on the Shimano drive unit and how often?

The Shimano 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 Ebike stop giving assistance over a certain speed?

Depending on where you've purchased your Keystone Fat Tire EBike 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 the Shimano battery life?

The Shimano battery life will be shorter during cold temperatures, this is not a sign of a problem.

- Will my Ebike be delivered with a charged battery?

The Keystone EBike will ship in a "sleep" mode with the battery at approximately 30% charge. It is recommended to fully charge your battery before the first ride.

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