SKU: 22856152285
e bike fatbike fully

e bike fatbike fully Keystone

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Description

e bike fatbike fully KeystoneIntroducing 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.


 


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Jennifer
Birmingham, US
★★★★★ 5
Honest Company making things right!
Color: 02 - Antique White, Size: California King, Color: 02 - Antique White, Size: California King
Love how this Californai sheet set feels and they fit very nicely on my bed. They are beautiful although I am unhappy with the 2 small holes I found in the fitted sheet after pulling them out of the packaging. I am past the return as I was not able to use them on my bed because I was moving and my bed was in storage. This is very disappointing for such a beautiful sheet set. UPDATE- I have reached out to the company and they were very kind and helpful. I stated the situation along with pictures and the order # and the company quickly responded with a new fitted sheet. Such a delight to find an honest company wanting to do the right thing. I Will order from this company again.
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Reviewed in the United States on May 7, 2026
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michele schmitz
Whiting, US
★★★★★ 3
Very thin. You get what you pay for.
Color: 01 - White, Size: Queen
You get what you pay for. I first noticed the softness which was great. The quality is very thin. They are cool which is great. I have not washed them yet. I would suggest washing them on cool and gentle by themselves. And because they are so thin I would fluff dry for an hour if you have that setting. The two things that damages clothes and sheets, etc. are if you have an agitator in your washer, those ruin clothes and the heat you choose for the fabric you’re drying I always wash my clothes on cold. I do not have an agitator anymore and on delicate and thin fabrics, I use fluff dry. It is cool, but it will dry, especially if it is thin and I’ve had to dry my fine delicates a little bit longer on fluff that way they don’t shrink because the shrinking comes in from the heat from the dryer so keep that in mind another good thing to remember if you got white sheets like I did is that when you use your detergent add a little bit of borax or laundry booster and they will help get them clean and sparkly white. I am on the fence about whether I would recommend this or not if you’re tight on money and you take good care of them I would recommend that you get them. I’m a linen freak and I buy mostly expensive sheets and I thought I would try this out so that’s where I’m at.
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Reviewed in the United States on May 26, 2026
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Jeff Gomske
Fort Morgan, US
★★★★★ 5
Astonishing, Fun, Entertaining, Fantastic
Format: Kindle
I consider The Martian my favorite fictional novel of the last 15-20 years. The movie was incredible in that they actually followed the book closer than 99% of other films based on books. It remains my favorite movie of the last 15 years or so as well. I don't know anyone (personally) that loves either of them as much as I do. With that said, I was REALLY looking forward to Artemis. It was good...but, it was certainly not in the same caliber as The Martian was (at least not for me). I enjoyed it a lot, however and appreciated how author Andy Weir chose to go in a completely different direction and not just rehash another similar story, which I am certain would have been great as well. As a result, I was cautious regarding Project Hail Mary. It sounded a little too close to The Martian, but yet, also different in that the circumstances simply could not be more opposite and the stakes so much higher. I'm trying to figure out the best way to summarize without giving too much away from this utterly compelling novel. As I read several reviews, I noticed a recurring theme: SCIENCE. Lots and LOTS of science. Holy cow, they were right. Many years ago I read Apollo 13 and Jim Lovell and his co-writer, try as they might, simply could not dumb down Orbital Mechanics anywhere near enough for me to have even a minor clue as to what they were attempting to say...I just skipped 90% of it and hoped that the sentences written afterwards, would help to make sense of what I had just skimmed over. I'm a lot of things, but a math wizard is definitely not one of them. Michael Crichton (Jurassic Park) had an amazing talent for dumbing-down the science of what he was trying to explain in ways that genuinely made sense (most of the time). Not everyone has this talent, and I would say Andy Weir falls squarely in between. He's certainly better than Jim Lovell, but not quite as good as Crichton. But then again, outside of a science textbook, I haven't really read anything with quite as MUCH science as Project Hail Mary. So maybe he's just as good, but he just puts more science into his books than Crichton, maybe that's it...? Either way, be prepared for a lot of astonishingly interesting science within the pages of this novel...and I DO mean a LOT. I don't say this to make you wary or steer you away...on the contrary, Andy Weir has a special talent for making hard science truly entertaining. The book opens with an absolutely amazing and frightening premise: an astronaut awakes from an induced coma to find the only other two people on board have died at some point along their journey...but it gets worse. He has no idea who he is, or why he's on the ship, and oh yeah, they look to be a long way from home. A really, REALLY long way from home. In fact, the sun he sees isn't actually OUR sun at all. He's managed to leave our solar system entirely. And he has no idea why. ((Minor Spoilers)) The book goes through some clever flash-backs, which set the stage for why the mission happens, and slowly, carefully explains how they managed to get so far away from earth in such a short amount of time. Basically, earth's sun seems to be dying. At the rate of decay, we have maybe 19 years left before the gradual cooling has catastrophic consequences resulting in the death of billions (best guess). Why the sun is dimming is quite the conundrum in the first place. Turns out it really isn't dying, it's being killed by an outside source...which turns out to be easily the greatest find in history. It's alien life, and they are using the sun for food, essentially. It's alien life, but not intelligent life. But still, wow! ALIENS, right??? After this monumental discovery, and some tremendous research done by the most improbable scientist, the investigation into what is happening and why and what to do about it expands exponentially to other nations in order to pool all the resources possible to hopefully save the sun, and by extension, the human race as well. They learn. A LOT. A plan is put together, and with the help of the newly discovered microscopic alien life, which can also double as a power source (along with a few other nifty surprises), they begin to create one last, Hail Mary that could very well be the last chance we might have to save earth. It's audacious. It's dangerous, and it is absolutely critical that it succeed. As our astronaut's memory slowly unravels, so does his identity: Ryland Grace. He's a teacher on earth. Just a science teacher. Not even a college professor. He's amazingly smart, though. But he's no astronaut...and certainly not one who would volunteer to go on a one-way mission to another solar system to "try" and save humanity. Yet here he is. Alone. light years from earth, trying to solve the biggest riddle in all of human history. Ryland accepts his situation, such as it is, with relative indifference (for the most part). It doesn't matter HOW he got here. He's here now and he may as well use that time to be as productive as possible, right? Along the way, he unravels even more information regarding the microscopic alien life which is slowly dimming our sun during some additional flashbacks. The aliens, dubbed, "Astrophage" are quite the galactic plague as it turns out. Stars all over the galaxy are also losing their light, all due to the little buggers. All that is, except one particular star named, Tau Ceti. Now why would that one star be unaffected by Astrophage, when every single star around it has been affected to some degree. The plan is to go there and figure it out and send the information back, hopefully in time to save the sun before the damage to earth is beyond repair. There is an incredible amount of stuff going on. The story switches from Tau Ceti to flashbacks of how the whole mission was planned and implemented (which is VERY entertaining, especially Director Stratt, who may actually be my favorite character in the entire novel). Weir is becoming quite adept at building tension, and abruptly switching the story from Tau Ceti back to earth and building more of the backstory then switching back to Tau Ceti. Keeping it all in check and most importantly, interesting all while mixing in a healthy dose of science, which I am to understand is pretty much all genuine, is quite the juggling act. I have long known science can be astronomically entertaining (see what I did there?) when done right...but unfortunately very few people in a position to teach science actually know the best way to create that interest in others. I can say without reservation, Andy Weir definitely knows how to do it...at least in written form. There is so much I want to say more regarding this truly phenomenal story, but I simply cannot without ruining a lot of the fun and surprises revealed along the way...and it is killing me to keep it locked in. Though I labeled a spoiler warning earlier, I don't think it gave away any more than what the author himself has revealed in interviews he has done regarding the book, and what you can glean from reading the summary here and just a couple other reviews. Tying all of that science together is truly astonishing to me. The creativity to put it into a novel that is remarkably exciting to read is nothing more than incredible talent. Kudo's to Andy Weir for not just hitting a home run, Project Hail Mary is a Grand Slam all the way. I truly did not want this story to end. By the way, I enjoyed the ending quite a bit. I don't know if everyone will. But it was fine for me. I think the ending screams "sequel" at some point too. A lot was left open-ended (IMO) and I wouldn't mind reading a follow-up to this. It doesn't HAVE to happen, but there are a lot of ways where the story could go if Andy chose to do it. Just sayin'. Just run out and buy this book.
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Reviewed in the United States on May 10, 2021
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Mahlon Everhart
Charlottesville, US
★★★★★ 5
Wonderful
Format: Kindle
The amount of detail in this book is so interesting and the specifics of so much theoretical ideas revolving around true ideas makes it so fun to read. The writer does a great job and describing every situation enough where you get the point but not too much to try to bore you . The book is very easy to follow, keeps you on your toes, was pretty funny to me, and truthfully just a great book for anyone!
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Reviewed in the United States on May 20, 2026
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Verified Purchase
John Haldane
West Palm Beach, US
★★★★★ 4
Read it in 2 days
Format: Paperback
This is science based science fiction. How refreshing to read science without turning the story into horror. Without a plethora of characters, it is easy to remember who is who. The story moves along well enough that I wanted to keep going. It us a p age turner in many respects. All this said, there were too many crises suddenly resolved like some Star Trek episode from 1966. It reached the point where I said to myself, "OK, this doesn't matter. Move along, nothing to see here." There was good humor, some surprising twists, and enough involvement with characters that I didn't want to put it down. As science fiction goes, it was good like pulp stories go. It wasn't like Ursula LeGuin or Robert Heinlein but I would probably pick up the next book he writes.
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Reviewed in the United States on May 21, 2026

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