2019 Biktrix Juggernaut Ultra FS Review

Biktrix Juggernaut Ultra Fs Electric Bike Review
Biktrix Juggernaut Ultra Fs
Biktrix Juggernaut Ultra Fs Sram Nx System
Biktrix Juggernaut Ultra Fs 100mm Travel Rear Suspension
Biktrix Juggernaut Ultra Fs Cockpit View
Biktrix Juggernaut Ultra Fs Rock Shox Bluto Front Suspension Fork
Biktrix Juggernaut Ultra Fs Display Controls Flat Locking Grips
Biktrix Juggernaught Ultra Fs Fat Tires
Biktrix Juggernaut Ultra Fs Banfang Mid Drive
Biktrix Juggernaut Ultra Fs Velo Plush Seat Hole Punched Rims
Biktrix Juggernaut Ultra Fs Front View
Biktrix Juggernaut Ultra Fs Rear View
Biktrix Juggernaut Ultra Fs Stock High Step Black
Biktrix Juggernaut Ultra Fs Stock High Step Ivory
Biktrix Juggernaut Ultra Fs Electric Bike Review
Biktrix Juggernaut Ultra Fs
Biktrix Juggernaut Ultra Fs Sram Nx System
Biktrix Juggernaut Ultra Fs 100mm Travel Rear Suspension
Biktrix Juggernaut Ultra Fs Cockpit View
Biktrix Juggernaut Ultra Fs Rock Shox Bluto Front Suspension Fork
Biktrix Juggernaut Ultra Fs Display Controls Flat Locking Grips
Biktrix Juggernaught Ultra Fs Fat Tires
Biktrix Juggernaut Ultra Fs Banfang Mid Drive
Biktrix Juggernaut Ultra Fs Velo Plush Seat Hole Punched Rims
Biktrix Juggernaut Ultra Fs Front View
Biktrix Juggernaut Ultra Fs Rear View
Biktrix Juggernaut Ultra Fs Stock High Step Black
Biktrix Juggernaut Ultra Fs Stock High Step Ivory


  • Purpose-designed fat-tire electric made for off-road use with a 1000-watt mid-drive motor, 14ah battery and top speed of 38mph, it looks like a bicycle but is classified more as a moped
  • Large 180mm, hydraulic disc brakes provide ample stopping power, which is great for an electric bike that goes as fast as this one, good weight distribution with the motor and battery mid-frame
  • The control center can be easily seen in direct sunlight and offers tons of pertinent information like speed, range, wattage output and more, with no rear suspension or seat post suspension it could get a little bumpy
  • Given the heavier weight, higher possible speeds here, and fat tires, it would have been great to see some even wider hub spacing and perhaps extra gussets to reduce frame flex

Video Review





2019 Juggernaut Ultra FS


$3,399 ($4,499 CAD)

Body Position:


Suggested Use:

Trail, Sand and Snow

Electric Bike Class:

Throttle on Demand (Class 2), Speed Pedelec (Class 3), Moped or Motorcycle (Class 4)
Learn more about Ebike classes


1 Year Limited


United States, Canada

Model Year:


Bicycle Details

Total Weight:

77.3 lbs (35.06 kg)

Battery Weight:

9 lbs (4.08 kg) (11.3lbs for 17.4ah and 21.0ah Batteries)

Motor Weight:

11.7 lbs (5.3 kg)

Frame Material:

6061 Aluminum Alloy

Frame Sizes:

19 in (48.26 cm)

Geometry Measurements:

Medium: 19” Seat Tube, 24” Reach, 28.5” Stand Over Height, 38” Minimum Saddle Height, 27” Width, 79” Length

Frame Types:


Frame Colors:

Matte Black with Neon Green Accents, Matte Silver with Neon Green Accents

Frame Fork Details:

Rockshox Bluto RL Air Suspension, 100mm Travel, Compression Adjust with Lockout, Preload Adjust, 150mm Hub Spacing, 15mm Thru Axle

Frame Rear Details:

DNM Burner RC3 Coil-Over Spring Suspension, Adjustable Rebound, Adjustable Compression, 190mm Hub Spacing, 12mm Thru Axle with Hex Bolt

Gearing Details:

11 Speed 1x9 Shimano Alivio Derailleur, Shimano HG Cassette 11-34 Tooth

Shifter Details:

SRAM NX1 Trigger Shifter


Lasco EB11, Alloy, 170mm Length, 42 Narrow/Wide Tooth Chainring with Double-Sided Alloy Chain Guard


Wellgo Platform Alloy with Fixed Pins


Tapered Headtube, 1-1/8" to 1-1/5"


Promax, Alloy, 100mm Length, Two 10mm Spacers


Promax, Alloy, 5° Rise, 5° Sweep, 690mm Length

Brake Details:

Tektro Dorado 710E Hydraulic Disc with 180mm Rotor Front and Rear, with Four-Finger Adjustable Levers with Motor Inhibitors and Shift Detection


Black Rubber with 3mm Locking Rings


Velo Plush with Gel, Black

Seat Post:

Rigid, Aluminium Alloy

Seat Post Length:

350 mm

Seat Post Diameter:

30.9 mm


Alloy, Single Wall, Punched Out, 36 Hole


Stainless Steel, 13 Gauge, Black with Stainless Nipples

Tire Brand:

Kenda Juggernaut, 26” x 4.0” (98-559)

Wheel Sizes:

26 in (66.04cm)

Tire Details:

5 to 30 PSI, 0.4 to 2.1 BAR

Tube Details:

Schrader Valve


Adjustable Length Kickstand at Rear, Independent Rear LED Light (Seat-Post Mounted), Optional Battery Upgrades (14ah, 17ah, 20ah), Optional Magura 4-Piston Hydraulic Disc Brakes Upgrade, Optional RST Guide Suspension Fork Upgrade


Locking Removable Downtube Semi-Integrated Battery Pack, 1lb 3 Amp Charger

Electronic Details

Motor Brand:


Motor Type:

Mid-Mounted Geared Motor
Learn more about Ebike motors

Motor Nominal Output:

750 watts

Motor Peak Output:

1000 watts

Motor Torque:

160 Newton meters

Battery Brand:


Battery Voltage:

48 volts (Optional 52v)

Battery Amp Hours:

14.5 ah (Optional 10ah or 21ah)

Battery Watt Hours:

696 wh (Optional 480wh or 1008wh)

Battery Chemistry:


Charge Time:

3 hours

Estimated Min Range:

9 miles (14 km)

Estimated Max Range:

30 miles (48 km)

Display Type:

Bafang DP C18.UART, Fixed LCD, Backlit, Adjustable Brightness (Double Tap Info Button, + and - and Info Buttons to Navigate, Hold + to Toggle Between Sport Mode and Eco Mode, Hold - to Enter Walk Mode, Hold Light Icon to Toggle Headlight and Backlight)


Battery Indicator (Percentage), Clock, Speed, Max Speed, Average Speed, Odometer, Tripometer, Range, Calories, Trip Timer, Pedal Assist (0-5) (Advanced Settings: Unit of Measurement, Brightness, Auto Off, Default Mode, Power View, SOC View, Trip Reset, Wheel Size, Speed Limit, AL Sensitivity, Password, Set Clock)

Display Accessories:

Independent Button Pad on Left

Drive Mode:

Advanced Pedal Assist (Measures Rear Wheel Speed and Pedal Cadence)

Top Speed:

28 mph (45 kph)(20 MPH Throttle Only, Optional 33+ MPH in Off-Road Mode)

Written Review

To run the forums, host the website, and travel, I charge a universal service fee for my reviews. This review was sponsored by Biktrix. My goal is to be transparent and unbiased, this video and written review are not meant to be an endorsement of Biktrix products.

Biktrix has gone full speed ahead for 2019 and with that full speed comes full suspension. What I am talking about today is the Juggernaut Ultra FS. It features full suspension, power battery, mid-drive motor from Bafang with a 1000watt nominally rated setup. Yep, that’s 1000 nominal, so it is capable of getting up to a massive 1350watts in power. Before we get into that, lets go over some of the features here. As stated before, it is full suspension and that is one of the areas of comfort. The front fork is a RockShox Bluto fat-tire specific fork while the rear suspension features 100mm of travel and some preload adjust. There are some other adjustments that can be made here, but it must be noted it is kind of tucked away into the suspension as shown in the video, so do be aware of that. The headtube is tapered, so you could even swap out for another fork in the front if you wanted. Another point of comfort here are these Kenda Juggernaut fat tires. These are 26” x 4” and have some great nobby tread that actually can help as little dampeners adding a bit of absorption, so overall, very comfortable for riding. The rims here are pushed out to save weight which is nice and they sport some super sturdy 13 gage spokes in the both the front and rear. Assisting even further in comfort is this slopped top tube for easy approachability as well as this Velo plush saddle. It’s so great that Biktrix is putting so much comfort on a ride that is also very capable and fast… really just a lot of reassurance from something so powerful. I am told that the final production version comes with battery integrated lights which is nice, but the one I tested today had no front light and just a AAA battery operated flashing attachable light in the rear. Other features include locking flat grips, aluminum alloy Wellgo pedals, and wide 120mm hub spacing with 12mm through axles.

Driving the Juggernaut Ultra FS to its top speed of 28mph is the Bafang Ultra geared mid-drive motor. This motor offers 1,000 watts of nominal power with up to 1,350 watts of peak power! But even more impressive is it’s 160 newton meters of torque. Yes… 160 Nm. It’s the torquiest motor I’ve personally tested and seems to fit the bike quite well. Compared to most Class 1 ebikes which offer 50 to 90 Nm, the 160 here can feel exciting but might also put increased strain on the drivetrain and frame. Powering up moderate hills was a breeze (literally) and for all but the most extreme hills, I was able to rely solely on the throttle without pedaling at all. When tackling real hill climbs – ones where I actually had to get out of the saddle – I found the torque made the difference between me having to get off and walk up. One of the coolest things about this particular motor is that it’s Bafang newest version, which replaces some of the lower power designs that used nylon gears inside, this one uses all steel components. This upgrade in internal parts should help the motor handle the extreme torque being produced and improve its overall longevity. Now, I mentioned the top pedal-assist speed is around 28mph, because technically the motor will continue providing pedal assist up to 36mph. I think it’s great that in addition to the guard plate, there is a guide accessory at the top to keep the chain from bouncing around and coming off at high speed as well as a narrow wide tooth pattern that locks onto the chain more securely. The torque sensor did a nice job of smoothly administering power equal to my output. So when I pushed lightly on the pedals, I got a little bit of assist; when I hammered down on them the motor unleashed all its power. The motor cutoff was also pretty quick, and cut power almost immediately after I stopped applying pressure on the pedals. I appreciate this aspect, especially with the high torque of the motor, as I’ve found that on some cadence sensor designs found on cheaper ebikes, the motor cutoff lags quite a bit, making navigating trails at slow speeds difficult and even a bit unstable and unpredictable. Mechanically, you get a nice SRAM NX 11-42tooth (which is a great range for climbing) cassette, and a 42 tooth chain ring up front. Stopping the Juggernaut is a set of great 180mm hydraulic disc brakes in both the front and rear.

Powering the bike is a 48v 14ah lithium ion battery pack. I would definitely consider this a high capacity battery pack and really necessary for that super powerful motor. But in case you wanted more juice, Biktrix offers battery upgrades on the bike to both a 17ah and a whopping 21ah, very cool! Anyway, the battery is mounted via lock and key, however, you don’t need the key to start the bike, it is just for battery security. The battery has a power button and I love the LED display read out on it so you can check to see round about how much juice is left. To really care for this and other lithium-ion packs, I have heard that storing in a cool dry location vs. extreme heat or cold will extend the life and try to keep it about 50% full when not using for long periods so you won’t stress the cells. Try not to let it run down to zero, because that’s really hard on the cell chemistry.

Another area worth mentioning here is the control center. I’m kind of a control center geek and I always love to see comprehensive stats while riding. The Bafang control center on the Juggernaut does just that. It displays pretty much everything, including current speed, top speed, average speed, range, battery level, pedal assist mode, wattage output and more. More importantly, I could read it in direct sunlight! The only downside to this display was that it’s not removable, so I might worry about it getting dinged up when the bike is being parked or transported and just taking more sun and rain damage over time. On the plus side though, it does have the ability to enable a passcode, adding another layer of security to the bike which is a bigger deal if you have kids around or are just concerned about safety. It does however angle, and I love that the controls can be pressed easily by your left hand since they are positioned well as to keep your eyes on the road.

When it is all said and done, I found the Juggernaut to be a ton of fun. The suspension and fat tires really give it a rugged quality that can handle anything, and the powerful motor is… really something that can leave you speechless! However, there are some tradeoffs here so I did want to call those out. The bike was really comfortable, but I did feel the icing on the cake would be to add a suspension seat post. It doesn’t come with one, but that can be fixed by stopping by your bike shop and having one installed. This setup didn’t come with rack, headlight, or fenders, but I am told the final version should have an integrated headlight, so that should help. And finally, the pricing can be a bit confusing. During the filming of this review, I found it hard to nail down an MSRP on the bike. However, I soon understood the reasoning behind this… Biktrix is a direct to consumer brand, and you can literally build your bike on their website! So while this may seem like a con, it is actually a bit more of a pro since you have flexibility in options and choices. This one I tested came in around $4058.99, but I am told they can range anywhere from $3,399-$6,198 respectively. The bike is really a blast and well put together, I would like to thank Biktrix for inviting me up to come check it out.

As always, I welcome questions and feedback in the comment section below. Whether you own a previous version of the bike, have taken a test ride, or are brand new to the space, my goal is to provide an objective and honest resource. You can also join the Biktrix Ebike forums and share your own photos, videos, and review updates to help others! Have fun out there, and ride safe :)


  •  Incredibly powerful and torquey Bafang Ultra motor with 1000 watt nominal output and 160 newton meters of torque makes climbing even the steepest hills possible, it also drives the bike to speeds of almost 40mph
  • Sram trigger shifters and derailleur are specifically designed for e-bikes and should be able to handle the power and torque coming out of the motor, they also shift incredibly smoothly and have built in shift sensors to cut power to the motor when shifting, preventing the components from enduring unnecessary strain
  • Massive 180mm hydraulic disc brakes provide ample stopping power, which is extremely important for an electric bike like this that can reach speeds close to 40 mph
  • Locking grips should ensure the grips stay in place even when tackling the most extreme trails,
    a nice little feature that in my opinion falls under the category of safety
  • Motor inhibitors cut power to the motor whenever the brakes are the levers are depressed, ensuring the rider isn’t fighting agains the motor when trying to stop, another great safety feature
  • Control center is easily visible even in direct sunlight and offers a plethora of information including current speed, max speed, average speed, battery level, range, pedal assist mode, wattage output and more
  • Rock Shox Bluto front suspension does a great job of soaking up hard hits and making for an overall pretty smooth ride, the rear suspension with 100mm of travel is great too
  • I love that the electric controls are reachable from your left hand without having to take your hand off the handlebars, it really keeps your eyes on the road
  • Wellgo aluminum alloy platform pedals are extra wide and grippy and help keep my feet in place even when hitting extra bumpy terrain
  • Torque sensor starts and stops power very quickly and accurately, matching the power output against my own, this is great for trying to ride slowly over tricky terrain
  • Battery has above average capacity of 14ah, and Biktrix also offer a 21ah battery, battery is locking and removable and even has a LED charge level readout
  • Gearing is good for high speed thanks to the 11-42 teeth cassette in the rear and 42 teeth chainring up front


  • The one I tested had no headlight, but I am told they will ship with one, so it might be something you want to double check when purchasing
  • Suspension adjustment is difficult in the rear, one of the areas you can configure is mounted under the spring in a very difficult to get to place
  • I did like the full suspension, but I did wish that it had a suspension seat post, it would really round off the comfort well
  • No fender bosses in the front so the only way to mount a fender is to find one that compression fits inside the stem
  • Control center can’t be removed, leaving it vulnerable to theft and scratching when the bike is left at a public bike rack
  • Only one frame size may limit the range of rider heights the bike can accommodate
  • At $3,399 for the standard version and all the way up to $6,198 for the top configuration, the Juggernaut is definitely an expensive electric bike and might not offer the utility of around town commuting because of it’s unclassified power and performance


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Comments (10) YouTube Comments

T Pierron
3 years ago

Great reveiw wondering what you thought of the Bulls E Bikes the fat tire monsters 18/19 for hunting with bosch mid drive and there weight carrying as well as reliability thank you Tom Pierron

3 years ago

I like the BULLS products in terms of availability from dealers and value for decent components and top-end drive systems. There’s another brand called Rambo Bikes that has hunting specific fat bikes (with camo and neat racks). Do a quick google search for them, we’re working on reviews to publish soon here but they aren’t live yet :)

Lou Buontempo
3 years ago

Should you run out battery power, can you still paddle the bike like a normal bike using leg power?

3 years ago

Hi Lou! Great questions. It’s best to keep lithium-ion Battery packs in cool dry environments and avoid extreme heat. You can help them last longer (holding up for more full charge cycles) but keeping the charge level between 20% and 80% so I would not recommend running them all the way down to zero… and yes, you can definitely pedal as you would with a normal non-electric bike. It will be heavier, but you could take the battery completely off if you wanted to. You should not experience any additional drag or slowdown just because it’s an ebike unless it uses a gearless direct drive motor, which introduces just a bit of magnetic drag, but is still very rideable ;)

Lou Buontempo
3 years ago

thank you keep up the great work !!!

3 years ago

Court, you have bulleted some specs that are different than in the video above. You said that MOTOR NOMINAL OUTPUT: 750 watts and MOTOR PEAK OUTPUT: 1000 watts and the video commented that MOTOR NOMINAL OUTPUT: 1000 watts and MOTOR PEAK OUTPUT: 1500 watts. I just wanted to clarify which is true? Per information coming from Biktrix, it clearly states the later specifications. Juggernaut Ultra FS 1000W rated, 1500W (peak) power.

3 years ago

Thanks for catching this, Clancy. Mikey covered this ebike, I was not involved and have not seen the Juggernaut Ultra FS up close. I’m reluctant to say which is true… and to be honest, it’s difficult for us to really test. Perhaps there was a mistake when he recorded the specs or perhaps Biktrix has updated their spec? Maybe they told us 750 watt nominal so as to fit into the light electric bike category vs. a moped/motorcycle. I’m not willing to make a stand here and say, because I’d be guessing. I will however, share this post with Mikey so he can provide some feedback and leave a comment of his own. If we got the wrong specs, I’ll make sure that they get updated in the review as well ;)

Robert Goldberg
3 years ago

By far the best bike I’ve ever had. It is also by far the most expensive one I’ve owned, but I do think it’s worth every penny.

I was interested in a fat e-bike with a lot of power, new technology, and quality materials and components that would take me anywhere, from beach cruising to black diamond trails. What I didn’t want was a motorcycle. I looked through dozens of fat e-bikes on EBR and narrowed it down to just a few. Although EBR reviews are usually highly detailed and helpful, for some reason the one on the Juggernaut was somewhat lacking. After weighing all the options I opted for Biktrix because it combined the highest quality components for a relatively affordable price when compared to other brands. And I don’t regret my choice at all.

For a bike, this is major purchase and so I wanted to give the most detailed review I could to help some folks out there in their decision making, especially because there is not that much info about this bike online.

Bicycle and experience overall – 4.5/5 This is an incredibly fast, powerful, sturdy bicycle with all very high quality components and it really does fit its name. Despite its incredible power, large size, and heavy weight – all attributes of a motorcycle – it is somehow still able to maintain a feel of a very mobile and versatile bicycle. The customer service was not bad, but has room for improvement.

Now let’s dive into the details:

Versatility 5/5: This is a fat mountain bike so its application is quite limited, right? WRONG. You can do literally anything on it, this is all of the bike types put in one. Road biking? Sure. Pump the tires up to 28psi, find the assistance mode on the motor where it takes off the weight of the bike and tire drag on the road, tighten the suspensions, and you’ve got yourself a sweet road bike. Want to go off the road? Loosen the suspension, take the tires down to 12-15psi, play with the assistance level, and you’ve got yourself one of the best off-road bikes there is with an uber soft ride thanks to the combination of full suspension and fat tires. Want to take on ridiculous hills that are impossible with regular bikes or even a lot of other e-bikes? Turn on the “sport” mode, and you have a ROCKET. All of these applications have another advantage: for the same effort your speed is higher and you cover way more distance, so the fun reaches new dimensions. Thus, your exercise triples because you just keep wanting to go out and ride. The air, the speed, and the power are just too addicting.

Power 5/5: Before the Juggernaut I got a $1,500 rear hub 750W motor fat ebike on Amazon. It was very powerful, but I was told by my local bike shop right away that the bike was just a beach cruiser and it would not hold up off-road. Only mid-drive motors are really built for trails. I didn’t listen, took it a few times to a fire road up a mountain and boy did I struggle with anything that was remotely a steep hill, where it would just give out and I’d have to pedal the entire weight of the bike on my own up the hill. I could barely do 1,000-1,500 feet of elevation before almost vomiting and fainting. Eventually it completely broke in the middle of a trail 3 miles into the woods and I had to drag it back on foot. For that reason I was skeptical about what a fat bike could handle in terms of hills, even with a powerful motor. When I got the Juggernaut I took it to the same fire road. HOLY COW, it really is an unstoppable beast. No exaggerating, with its 1,500W mid-drive motor it can climb pretty much anything but a vertical wall. Switch it to the ECO mode, and that climbing power is spread out over very long distances. It took me to the top of Mount Wilson 5,700 feet high on my very first try. There are some brands, like Luna Cycle, who use different controllers and take the motor up to 2,000W and higher, but to me that is just an overkill. The power that the Juggernaut packs is incredible and more than enough for any application you can think of. You can take it over 30-35mph in a blink of an eye. Anything over that I don’t feel is a bicycle territory anyway, that’s a motorcycle.

Motor 5/5:

  • The Bafang motor really is a masterpiece. Sure, it’s a Chinese brand, but it’s the biggest one in China and very popular everywhere in Europe and the US. No other mid-drive motor on the market can surpass its power. Maybe Bosch and other European motors are more reliable, but I’ve been digging online and all I see is praise for the reliability and the power of the Bafang motors. There are some videos online with the tear down of the Ultra motor and it really is a fool-proof design with what seems like decades of potential reliable performance.
  • The torque sensor is just a joy to use, especially on a tight trail. Somehow it knows exactly how much power you need and gives you just that. When you stop pedaling, it immediately cuts the power to the motor, which is especially important on tight corners. All this makes climbing a trail a pure joy. I never thought I would say this, but I now actually enjoy climbing trails more than going down them. It is so much more technical and interesting and with the Juggernaut’s power and torque sensor and it is just a blast.
  • The casing of the motor is extremely strong. I’ve had the entire bike fall and rest on a rock just with the motor, but that didn’t make a tiniest dent in the casing.
  • The motor is also a sealed system, which requires special proprietary tools to access the inside, and not everyone has them. There are bike shops around who can service the motor if you need to. What this also means is that the motor is built to last a very long time before needing to be serviced. I am still trying to figure our the best servicing interval for it, but I’ve read online that it’s around 1K miles. Either way, I still haven’t had a single issue with it and it works beautifully even in the California dust.
  • It is also very quiet and surprisingly small for such amount of power. For those who know what an ebike is you can easily tell it’s there, but I’ve had many people tell me they thought it was a regular bike and had no idea it had a motor, or a battery.

Sturdiness 5/5:

  • I’ve thrown everything I had at it, including myself, but the Juggernaut doesn’t care. It can take on anything. I took it on black diamond trails, rocky fire roads, Southern California mountains with the unforgiving dust that covers and eats through everything. The bike takes it all like a champ.
  • I took a heavy tumble on a trail once falling on the handle bar with my chest and breaking several ribs, while the bike itself crashed into a tree with the wheel turned 90 degrees to the trail. I myself barely got home. The bike? Didn’t even notice the fall, the wheels straight as they were out of the box, the motor purring like a kitten, all electronics working like a charm. Basically the Juggernaut just smirked, winked at me, and took me home.

Frame 4/5:

  • The frame is very solid and feels like it could easily withstand some major abuse. It’s 19″ suited for riders that are between 5’6″ and 6’4″ and works great for me at 6’1”.
  • The first reason for 4/5 is that I had the bearing in the lower pivot point of the frame go loose on me all the time and it needed to be replaced.
  • The second reason is that I wish the battery integration into the frame was a little more seamless. I do like how easy it is to put it in and the fact that you can take it out of the frame only with a key, but do not need a key to turn the bike on. But the locking bracket that connects the battery to the frame is plastic and does not feel 100% reliable. The battery is also not completely flush to the frame once locked in. It doesn’t move at all and the space it leaves under it is tiny, maybe a few millimeters, but that nonetheless leaves an unpleasant impression of a weak point in a bike with such a solid construction everywhere else. My 21A battery now has a small travel in it when locked into the frame and moves around in the bracket, which makes an annoying squeaking sound. Compared to other fat e-bikes and biktrix own previous designs where the battery just looked glued onto the frame, the Ultra FS looks infinitely better. But it is still not perfect and I would want to see the battery locked into the bike with a metal bracket and be completely unnoticeable until you have to take it out.
  • Third, I wish the transition between the motor and the frame was smoother and it was more seamlessly integrated into the rest of the bike. They did a good job, but the transition point is still easily distinguishable. Some other bike brands did a slightly better job at that, like Luna’s X-1 Enduro or some of the M2S bikes.
  • Finally, I wish they had options for a rear rack, especially if you have a spare battery. The batteries are too massive to carry in a backpack and having an option to attach a spare to the bike would be great. A full suspension bike is not easy to find a rack for. They sent me an article with a variety of after-market racks, but I ended up getting one on amazon, which attaches to the seat post and modified it so that it had two places of contact. That gives the rack more stability and I haven’t had any issues with it so far, even on the roughest of trails. Except for one, which is I can’t ride without holding the handle bar with that rack on the seat post, because it causes a small wobble in the frame that is eventually transmitted to the front wheel. Maybe I’ll get a different rack later on.

Kickstand 5/5: The kickstand is huge and very strong and is bolted to the frame very firmly. One of the Biktrix videos with someone riding the Juggernaut showed it dangling and loose and I was worried about that, but I’m happy to say that it’s not at all the case. It is a perfect kick stand that can easily hold the entire weight of the bike and is completely rigid when riding the bike or when deployed.

Breaks 5/5:

  • You really do need the hydraulic breaks for this monster and it pays off. Unbelievable power, responsiveness, and quietness of the breaks. The pads are high performance metal ceramic type D40.11, which are made specifically for very fast and heavy e-bikes. Nonetheless, despite their metallic compound they are still very quiet. No other pads work for these breaks and they are not easy to find online when you need replacements, but I was able to locate a couple of shops in CA who sell them online.
  • I’ve never felt this comfortable with breaks on a bike before. You can come to a complete stop with a very impressive stopping distance if you engage both rear and front breaks, which is also aided by the grip of the fat tires and the bike’s weight pushing those tires into the ground. The only downside is that they wear out fairly quickly. I’ve just had to replace the pads in the back, though the front ones are only half way worn so far. Mind you, that is after A LOT of trail riding and descending thousands of feet of elevation on steep fire roads on 70% of the rides I took it on. And that is in the unforgiving Southern California dust where breaks go like there is no tomorrow.
  • Engaging the breaks immediately cuts power to the motor, even if the pads don’t touch the rotor yet, which is nice if you quickly need to stop the motor for a moment while still pedaling and without losing speed. I use that also when I’m approaching a light and need to switch to the lowest gear without the motor kicking in.
  • It is a treat how little maintenance these breaks require. Once you adjust them in the very beginning after installing the wheels, you can forget about them. They are self adjusting and always give you the incredible stopping power, but never rub on the rotor. Just make sure to keep them clean of any oil or contaminants.

Drivetrain 5/5:

  • All components are top notch. The cassette is 11 speed, which is a lot for a fat ebike and gives you a wide range of the gears to choose from, making it feel really like a bike rather than a motorcycle.
  • The derailleur is so smooth and responsive it’s just a joy to use it. It switches the gears almost instantaneously and so softly you barely notice it. It was set up right out of the box and I haven’t had to adjust it once, even after taking the wheel off multiple times. The controller on the handle bar does not have an indicator for the gears, which is apparently a newer trend in biking industry, but I quickly got used to that and go by feel or quickly looking down.
  • The gear switching sensor works great and gives you a one second pause to allow the chain to switch gears without the motor ripping on it in the process. Most of the time the derailleur works so fast that the pause feels too long. It did fail on me once or twice, especially when in “sport” mode and switching down (to a higher radius sprocket), which produced a disturbing sound of metal grinding, but to my surprise everything was ok afterwards. I also noticed that the duration of the pause varies depending on your effort and the gear you’re in. My thought is that another feature of the sensor is such that when you’re in the optimal position to switch to a higher gear based on the bike’s speed and the motor’s load, the pause will be extremely small to none at all. That may not be a feature and just another fault, but I actually like that part because it makes for a much smoother and faster shifting experience with the motor immediately starting to use the new gear after the switch with no pauses. I haven’t noticed that happening when switching to a lower gear.
  • The crank is very solid and is surrounded by two massive chain rings. I’ve had the bike bottom out on a rock with the chainring and it had nothing but a tiny scratch. Definitely a nice touch.
  • When you move the pedals the whole system has a small amount of play in it, which I was initially concerned about. But turns out that is normal and accounts for the coupling between the crank and the motor gears.
  • The chain is KMC with masterlinks, which is apparently the best chain you can get for a mid-drive system.
  • I clean and lube the whole drivetrain system after every off-road trip. That is crucial in California dust to keep the drivetrain performing well for a long time. I may ride 2-3 times on the beach before cleaning everything, but that is always on paved paths with little to no sand on them.
  • The only downside I noticed was that the chain rubs on the inside of the frame closest to the cassette when in the highest gear. It is not a deal breaker, especially because I don’t use that gear that often on such a heavy bike, but I wonder if that would wear out my chain quicker and if an extra washer would fix the issue.

Battery 3/5:

  • I bought two batteries, one 21A with the bike and later a 17.5A. From the very beginning I was not thrilled with the range because I expected a lot from the huge 21A battery. The most I would get with very economical riding approach (95% of the time in ECO 1) was 55-60 miles. That is still A LOT of miles for a fat ebike, but way under the advertised range for the battery. I did everything I could to maximize the range, including pumping the tires to 30fps, keeping assist mode on the lowest setting, smart use of the gears not letting the motor struggle from dead stop on the highest gear, and not using the throttle at all. Sometimes I would even turn the assist mode to 0 and pedal myself on the even sections of the road or downhill. The estimated range on the screen would be all over the place and often give me lower range than I was actually able to do. What baffled me even more was that even when the screen showed me 5% left in the battery, the little indicator on the battery itself showed me 2/4 bars, meaning there was more juice left that the computer could use, but for some reason didn’t see. Imagine my surprise when I got the 17.5A battery and the estimated range displayed on the screen for both fully charged batteries was exactly the same. Finally, when going to the settings in the computer it would not give me any information about the battery, all items would be blank. The voltage of both batteries, however, was fine, albeit when charging the batteries it would not go higher than 97-98%.
  • After A LOT of research, full load tests of the batteries through a local e-bike manufacturer, and dozens of emails with Biktrix, I was finally able to get to the bottom of this all. Turns out many of the features of the computer, including accurate range estimate and battery info are lost because Biktrix use Dorado batteries, which is a different (bigger and better) battery brand from Bafang. Furthermore, Biktrix places a fuse inside the batteries that prevents them from being overcharged thus prolonging their longevity, hence the highest charge you can get is 98%. Finally, they set the low voltage cut-off (LVC) of the battery at 44V, another attempt to improve the longevity of the battery. That is because if the battery level is less than 10%, a sudden drop in voltage from something like pushing a throttle up a hill without a cut-off limit can damage the battery. They sent me a table with the voltage-percentage ratios of the batteries and 44V corresponds to 32%, which means that you still have close to 30% of the battery juice left when the percentage displayed on the screen is below 5% and the pedal assist is almost out. There is an option to change this setting to 43V or lower with a special USB programming cable, which I haven’t done yet, but most likely will to increase the range of the batteries.
  • Overall, a lot of issues with and lower than advertised range of the batteries place them at 3/5.
  • Weight and balance 4/5: Don’t expect it to be light. It is heavy and drags you down if you have to balance on foot in tight and steep corners. Hence 4/5. But why 4 and not lower? Despite packing so much power and battery and the fact that it’s fat, when compared to other e-bikes it is not that much heavier. Furthermore, the placement of the motor low and in the middle of the bike makes it very maneuverable and you don’t feel its weight at all when riding and climbing trails. Until you have to drag it across a rockslide that is. But even then, the walk mode makes it infinitely easier to pull it over rocks or unridable terrain. Just hold the “-“ button down and in 2 seconds the motor starts to slowly turn but with enough kick for you to climb a lot of steep rocks.

    Computer 4/5:

    • The color LCD screen works great. It is huge compared to other e-bike brands screens and has a superb resolution/visibility, vivid colors, and zero glare. I can see everything on it extremely well in any light conditions. It automatically adjusts brightness based on the amount of light in your surroundings. If you hook up a light to the computer, it will automatically turn that on too in low light conditions. When I got my bike it had a wire for the front light coming from the downtube with the other wires. I just hooked it up to the light they sent me and it now works as an integrated light.
    • The dial of speed and power usage work great and are pretty accurate. I like the feature of being able to tell how much power of the motor I am using at a given moment.
    • It has a multitude of settings that you can enter by quickly pressing “i” twice. You can switch between the percentage and voltage for the battery indicator, change light sensitivity, remove the speed limit, change the distance unit, and many more adjustments.
    • Another one of the features I love is that you can set the assist mode to 0. That way the motor is turned off, but you can still see your speed, odometer, etc, which is a great feature.
    • The lost features of the battery info and useless range estimate cost the computer a star.

    Electrical system 5/5: No issues whatsoever after 500 miles so far. All cables feel heavy duty and take a lot of beating. They are also all organized extremely well and nothing sticks out or dangles anywhere, yet they have just the right length for the optimal range of motion in all parts of the bike.

    Suspension 5/5:

    • I went with the Rock Shox Bluto and boy am I glad I did. No wonder they are the leaders in the suspension market, because it is just perfect. You can adjust sag, rebound, and damping. Once you get it set up for your riding style and conditions, the ride quality is stellar. It gives just the right amount of everything. This fork deserves a separate review, and this is not the place for it. As for the Wren fork, I’ve read a lot of negative reviews about it, so I think the Bluto is perfect for this bike.
    • I don’t have a car rack so in order to fit the bike into my car I have to take the front wheel off. Every time I do that I want to hug the designer at Rock Shox because they made it just so damn easy. The wheel fits into the slots in the fork like a plug into an outlet. There is no adjusting, just slide the maxle through, tighten with a torque wrench, done.
    • The rear suspension is DNM Bruner RCP, which is a combination of air for compression and rebound and spring for sag. You can change the rebound and compression, although the rebound knob is buried in the frame and pretty hard to get to. There is not much adjustments in the spring, however. Thankfully it works well for my weight range and I don’t really have any complaints about it. Although I am not sure why they went with this suspension and not just an air shock, like again Rock Shox or something. The price of the latter is higher, but for a 4K+ bike the difference is not ground breaking.

    Wheels 5/5: Believe it or not, when I took the wheels out of the box my first thought was: “What the hell, are these plastic?!” They are that light. I could not believe how such massive fat rims could weigh so little. And yet the strength is unparalleled.

    Tires 5/5:

    • Although less fat and aggressive looking than other fat bike tires, they are still 4” and I found them to have an ideal balance between off- and on-road biking. They have enough grip to climb the craziest single tracks when at low PSI, and yet when pumped all the way up they don’t stick to the asphalt like glue and slow you down. Again, they are a Chinese brand Kenda tires, but so far I’ve been very happy with them. Only had one puncture with a thorn and replacing the tube did the trick. So far nothing since then.
    • You get slightly less control when road biking on low psi, probably because they stick to the road more and it’s harder to turn the wheel, but still quite ridable and not a deal breaker.

    Seat 1/5: The seat is a wood board. But that is the same in all bike brands. They all ship their bikes out with the most basic seats. For an ebike that can cover a lot of miles over many hours, that seat is not really acceptable. I ended up using my own Serfas RX-921L seat for mountain biking, and also bought an extra wide and soft seat for long beach cruising.

    Seat post 5/5: The seat post is 31.6mm and is very heavy duty, which is why I am able to put a rack on it with a spare battery. Not the lightest, but compared to the weight of the rest of the bike does not make any difference.

    The looks 4.5/5:

    • It is no doubt a giant head turner. Whenever I take it beach cruising, 95% of people twist their heads out and can’t stop looking at it. Some of them even stop and watch it go by in awe, and some give me thumbs up. One person came up to me and said “This is not the kind of bike you leave anywhere, right? You just take it out of your car, ride it, put it right back in the car, and lock it real well.”
    • I originally ordered a black one, but turned out it was sold out, so I had to get the gray frame. I’m so glad I did. It is a very nice warm metallic gray color and I feel the bike looks and stands out much better in that color. When Roshan called me to tell me that they had no black frames left, I asked him to combine the red accents on the frame with the red rim inserts, even though I upgraded my fork to Bluto which comes with green accents. They had no problem doing that and it came out awesome.
    • I don’t feel applying the black decals to the black fork is a good choice, because you just can’t see the “Rock Shox” letters at all and it all blends together into one black background. I got a set of red Rock Shox decals on amazon and it looks much better now.
    • The bike itself is not too over-designed and out of the box looks good, aggressive, but IMHO a little too reserved, especially for a fat bike with such an outstanding name. There are plenty of blank areas on the frame and battery, which my guess were left intentionally for the owner to customize the bike to their liking. I ended up adding some more decals here and there, including on the battery itself and now it looks much better.
    • I feel the battery design does not look very balanced with the frame. Maybe it’s because my frame is gray and the battery looks more in place with the black frame, but that is something they should take into account when considering different frame colors. The plain matte black and square angles of the battery are a bit of an eye sore next to the gorgeous shine and curves of the gray frame. My 21A battery came with “Biktrix” decals on it, but I feel that’s not enough. I put some decals on the battery and it looks much better now.

    Customer service 4/5:

    • Although Biktrix is a good company to deal with, my whole experience gets only 4/5, with a stretch.
    • Fist of all, when I got the bike, it was packed well, but not as well as I’ve seen others’ Juggernauts packed from their reviews online. It came with no manuals whatsoever on how to assemble the bike or set up the fork or the rear suspension, or how to bedd in the breaks, or set up the computer. Nothing. Their website also mentioned an integrated light, but I received a regular standalone light and again, there were no instructions on installation. It took quite a few emails from me for them to finally address that issue and send me the correct light with instructions, as well as a special bracket for it. They also eventually sent me the manuals, but that was after I was forced to look everything up online and figure things out myself.
    • Speaking of emails, their response rate is quite random. Sometimes I get a response from Roshan himself within minutes of my email to the general support address (mostly when I wanted to purchase another battery), other times it took days to weeks for them to answer my emails. They did try their best to address my issues, provide helpful online resources, and stand by their warranty, which so far had to cover the battery testing and the faulty frame bearing. The latter they sent me over mail and wrote an extensive manual online with images detailing the replacement process.
    • Many times I felt like a nuisance emailing them and asking for things that should have been done from the very beginning, and I really should not feel that way as a customer. I even had a conflict with Roshan at some point because of this very issue, but I have to say he handled it well and overall I was satisfied with the outcome, although the whole thing left me with a little bit of an unpleasant aftertaste.
    • I sometimes wonder if their main support person, Alex, was on vacation, because when he finally started answering my emails, all issues and questions were resolved almost instantly thanks to his detailed responses.
    • The online chat person does not alway answer the questions right. For instance, before buying the bike I asked what the rear suspension was, because I saw a spring as well as an air chamber with dials attached to it. The response I got was: “As you can see on the picture, it is a spring suspension.” Uh, yeah, thanks, not very helpful, and incorrect.
    • Finally, I do wish there was more information on the bike on their website, with more detailed descriptions of the components, such as batteries, breaks, shocks, chain, rims, tires, seat post size, frame size, etc.
    • To conclude, I feel this is a very trustworthy company that you can definitely feel safe buying from and confident in their 100% support after the purchase. However, in my experience they came through as somewhat reckless. Definitely not a deal breaker and their stellar product at a competitive price compensates for such shortfalls, but there’s definitely room for improvement.
    3 years ago

    Hi Robert! Wow, that’s the best comment we’ve ever received here. I’m impressed, thank you for going into more detail. I agree that some of the reviews done here by new contributors have lacked the depth (and accuracy) that I strive for. My goal has been to grow the number of different bikes and do our best, but I realize there’s a bit of compromise in doing that vs. doing every review myself. In any case, I sincerely just want to say thanks, I learned a lot from your comment and did some editing to make it look great for other people who come to the page. Enjoy the bike! Reach out anytime :D

    Robert Goldberg
    3 years ago

    Hi Court. My pleasure! Your website is awesome and was hugely helpful to me when choosing the bike. Your reviews are always fantastic and so detailed. Thank you for doing what you’re doing and for being there. Being able to contribute a little is the least I could do. Cheers!

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