Keystone - Electric Fat Bike⚡

The Keystone is my first e-bike having been a fat tire mtb enthusiast this was a no brainer, it is the most fun I’ve had on a fat tire bike. Love it !! thanks Borealis.

This is my third eFat and although I liked other two - the Keystone is just beyond. I set mine up with a Redshift ShockStop seatpost (hardtail with benefits!), Ergotec 45 degree by 50 stem, carbon riser bar, and Schwalbe Al Mighty 4.8 tires (328 Billy Flamingo studs per baby!) The T-type drivetrain blew me away so much I converted my other bikes.

I also received unbelievable service from the Borealis sales rep during purchase.

Simply heaven!

I’ve never written a review before, but lets give this a shot.

My journey started with a my buddy buying an analog fatty and encouraging me into following him. I’m 63 years old, live at 8,400ft elevation in Eastern Sierra, been riding eMTN bike several times a week for just over a year, and it seams like everything I ride is uphill. I tried my buddy’s bike and I could not climb my normal route (1,000ft/7miles). I began researching fatty eMTN bike and quickly found Borealis Keystone. I lamented for several weeks and pulled the trigger early November 2024.

I had questions on choosing the right tires/wheels. The staff was very helpful discussing my riding style/needs and helping me select the right combination (26”, 4.8”).

The bike arrived 3 weeks later (delayed at my request d/t travel). It was meticulously packed and I assembled it on my workbench/clamp. It took about 4 hours (I’m kind of slow and it was the first time. I had not changed my own tire in 50 years). I called the shop for assistance in assembling/sequencing the rings at the head tube. They were quite helpful and got me back on track. I was surprised to learn the bike did not include pedals and it took me several days to acquire some. [Recommendation to Borealis, give options to choose pedals/opt out during the purchase process, just like tires and wheels].

This bike has exceeded every expectation. It handles soundly. Shifting and breaking were flawless without any user adjustments. I can travel uphill/downhill with confidence.

Regarding the battery/range. My ride last week (1hr:43min, 2,746ft elevation gain, and 14 miles) left me using 40% of the battery. I failed to charge that night. I followed this with a longer/steeper ride/climb (3 hrs, 3,865ft, 25 miles) and ran my battery dry in the last 1/2 mile. I mostly ride in ECO mode and occasionally use TRAIL and seldom use BOOST. I can conclude that if you need more than 5 hrs and 6,600 elevation gain, and 40 miles, on 3-5 psi, then you might consider carrying an additional battery.

Regarding versatility, during these two rides above, I traveled on snow, ice, sand, rock garden, slush, hard pack road base, gravel, asphalt, and 12” deep creek. During these two rides, I only lost control when crossing the creek and found an unexpectedly deep rut. This caused me to step off my bike. On other rides, I went down when hitting ice as I did not opt to put studs in the tires (live and learn).

There is truly no terrain this bike cannot handle (however, I recommend considering studs for ice, I have not tried this option).

Today, I noticed my rear brake was soft and the lever pulled back to the bar. I had to stop my ride. I’ll take it locally for a bleed tomorrow morning and hope to ride in the afternoon.

If you want to HAVE A BLAST on the mountain or just want to expand your riding season to 12 months a year, this bike is for you!

After tons of research and very high expectations, I ordered a Keystone. The bike came very well packaged and set up perfectly and assembly was very easy. So far, the bike has exceeded my expectations especially on single track. I ordered mine with Mulefut 27.5” x 65 mm wheels and 4.3 Yippee Ki Yay tires. The set up rolls over everything and really sticks to the ground no matter what the trail throws at it. They are a great all around tire.
The fork set up for me was very quick and easy and performance is great matching the rest of the bike.
Electronic shifting is buttery smooth and very sweet.
Shimano EP8 is very seamless, yet makes me feel like Superman when needed. The bike climbs steep and loose hills like nothing. I can’t recommend the bike enough. My only recommended change would be to the handlebar grips. I couldn’t wrap my fingers around them and my hands slipped, I replaced with round.
Overall, I am thrilled with this purchase and ride it as much as possible. I am an older rider(63) getting back into mountain biking and loving this bike! Thank you Steve and Borealis Crew!

Jumps well, absolutely rips through snow and is just fun with whatever you’re doing! It’s my favorite e-bike on the market!