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Description
fatbike e-bike fully ELECTRIC FAT TIRE E-BIKEIntroducing 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
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. |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.4 ★★★★★
Based on 20 reviews
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Product Reviews
★★★★★ 5
Pandora’s Pain, Power, and Passion
Format: Kindle
I absolutely love this new world Lyra Winters has created! The spin on a Demon Academy setting was fresh, unique, and completely addictive.
Pandora is a character who immediately captured my heart. Thought to be powerless and enduring years of brutal abuse from her mother, it’s no surprise that her powers emerge at the exact moment she needs them most. After her mother’s death, Pandora discovers her father is none other than Death himself, a soul eater with a dark legacy. Her journey at the academy is anything but easy, filled with challenges tied to her father’s infamous reputation, her barely controlled abilities, and the cruelty of those around her.
Pandora is easy to root for, you feel every ounce of her pain, resilience, and growth. Along the way she meets Reed, a half-human dream demon who’s kind, steady, and the kind of friend everyone wishes they had. There’s also Hunter, a vengeance demon and counselor connected to her father, who adds another intriguing layer to her story. Then there are the bullies: Dexter, a brooding shadow demon; Bram, a chaos demon with a drinking problem and deep hatred for demon nobility; and Skel, a fear demon wrestling with his own darkness. They might hurt her, but they also can’t seem to stay away when she’s in danger, making for some deliciously complicated dynamics.
This book hits so many of my favorite tropes: friends to lovers, enemies to lovers, and of course, the irresistible “who hurt you?” storyline. I devoured it, and I’m already diving straight into book two!
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Reviewed in the United States on September 4, 2025
★★★★★ 5
So good!
Format: Kindle
Oh my goodness! What did I just read? Lyra Winters you have some serious explaining to do! That cliffhanger killed me! I am so happy to be back in the world of Kalista. This is definitely darker than Fates Hollow but oh so good. This is a fated mates reverse harem which I absolutely love.
Pandora had a very hard and rough upbringing. She lives in pain constantly and it makes it hard on her. She struggles with everything because she was kept so isolated and is new to her magic. Pandora gets sent to the Reform Academy and all of them have reasons why they are there. I love how, after everything she has been through, she is still a nice person. She is growing and becoming stronger too. Love her character.
The guys all act like jerks at first but all have a back story that helps understand why even though want to smack them. I'm here for the groveling that I'm sure will come. I love them all. They each bring something for her. They are all drawn to her though.
This is a slow burn book but there will be more books in the series so sure it will build. Man, that cliffhanger was a doozy and need book 2 now!
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Reviewed in the United States on June 3, 2024
★★★★★ 3
Good-ish
Format: Kindle
🌶️ 0/5
⭐️ 3/5
I will preface this by saying I am not a huge RH fan. However it didn’t feel like a RH quite yet. The relationships and plot are all building in this book. At first I was thinking things were happening stupid fast since she’s had zero interaction with another being and has been tortured her whole life, and I believe they were for one side of the relationship, but by 50% things moved too slow lol. Idk I think the main 1-3 guys I’m actually interested in more than the others didn’t get enough air time so I hope the next book things start moving with them since it ended the way it did.
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Reviewed in the United States on April 12, 2025
★★★★★ 5
Can I have Term 2 now?
Format: Kindle
This is by far my favorite book of Lyra's to date. I gobbled this book up so fast, I was so upset I finished it. I know this is going to be a book I reread, just like Fate Hollow Academy.
I loved Fate Hollow Academy, so I was excited when Lyra announced she was taking us readers back to Kalista. Although the characters from Fate Hollow are mentioned several times throughout the book, this book is about Pandora and her love interests in the Demon Realm.
Before you deep dive into this book, definitely look at the trigger warnings before you start. When Lyra says there's dark themes in this book, she meant it. Also, just know this book does end on a cliffhanger and will probably leave you with as many questions as it did me.
Below may contain some minor spoilers, so keep that in mind if you want to keep reading my review.
Pandora's first 2 decades of her life are full of torture, hatred, and confinement in a cellar. That is until her father finds her and brings her into the world she was supposed to live in. Because of her upbringing she wasn't acclimated to the Demon world and the way their society works so when she is offered the chance to go to a Demon Reform Accademy, she accepts it to learn the ways of society and how she is supposed to feed.
Pandora isn't like the other common demons in this world, no. She, like her father Death, are soul-eaters. Pandora is too scared to release her powers because she doesn't want to kill anyone, so she needs to learn how to feed off of a piece of soul instead of taking the whole thing.
Because of who her father is, she's classed as a Noble, and while she doesn't agree with her fellow Noble students, who look down on the "lower" class, she also is faced with 3 Demons who hate her for being a Noble. Theses a lot of back and forth tension which these 3 demons who have issues of their own. One is obsessed with her, and wants to know all of her secrets. One leaks fear all over the place, but also is scared of the "princess" -wink- -wink-. One is a complete drunk who doesn't like her just because he's got family Noble problems.
Don't worry, there are 2 other demons who are just the sweetest towards her. One who will get vengeance for anything done to her, he's got Golden Retriever energy around her and touch her and die energy for anyone around her. Finally, there is one who is friends with her even when the whole school is scared of her, who brings her into his dreams and will create nightmares for those who bother her.
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Reviewed in the United States on June 4, 2024
★★★★★ 4
This was more than I expected...
Format: Kindle
So...I finished this book at nearly 2am! It was just that hard to put down. I loved that it's set in the same world as Fates Hollow but in the future. Poor Pandora has been through so much but there's light at the end of the tunnel for her. She finally meets her dad and it turns out he's amazing. In order to help her learn about demon society and how to control her magic he sends her to the Demon Reform Academy. There she meets 2 awesome demons who help her and care for her. She also sadly meets her 3 tormentors. I will say though that while they do bully Pandora they also rescue her several times and defend her. They too have traumatizing pasts and can't see the good that is in front of them. Of course demon society needs to be shaken up too since that's part of the problem. I really enjoyed this read. I teared up a few times throughout the book but I liked the characters and that ending...well it looks like 3 in denial are going to need to grovel hard.
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Reviewed in the United States on June 1, 2024