Name: Juggernaut Ultra FS Pro AUTO
Brand: Biktrix Electric Bikes
SKU: JULFSPL264BK3-AUTO
Price: 3572.0 GBP
Availability: InStock
Rating: 4.71 (270 reviews)

1000W Mid-Drive

Motor Power

52V 17Ah 910Wh

est. 45mi Range

+5'8ft / 265lb

Max Load

Torque Sensor

Powerful Pedal Assist

25+ Point Quality

Control Checklist

Juggernaut Ultra FS Pro AUTO

£3,572

Get ready for a full-suspension fat tire eBike built around serious power, automatic shifting, and the flexibility to ride farther. The Juggernaut Ultra FS Pro AUTO combines the proven Bafang Ultra M620 mid-drive with a new Bafang A510 5-speed automatic internally geared hub, giving you the power to tackle demanding terrain without the need to constantly manage your gears.

Features:

1000W Bafang Ultra M620 Mid-Drive Motor: Delivers strong, responsive power through the bike's gearing, giving you the capability to tackle steep climbs, rough trails, and heavy loads.
Bafang A510 5-Speed Automatic Hub: Automatically shifts through five internally geared ratios as your speed and terrain change, keeping the M620 in a useful gear without constant manual shifting.
160Nm of Torque: Provides the low-speed pulling power needed for steep climbs, technical terrain, and carrying heavier loads.
265lb Load Capacity: Supports you and your gear without compromising the bike's intended performance.
On-Demand Throttle: Access motor assistance without pedaling when you need an extra boost from a stop, on a climb, or through challenging terrain.
Cadence + Torque Sensor: Combines pedal movement with rider input to deliver responsive, controlled assistance that feels natural under power.
52V 17Ah Battery: Includes a 52V 17Ah battery and charger, with the ability to add a second battery for substantially more available capacity and longer rides.

Benefits:

Automatic Shifting: Let the A510 manage gear changes while the Ultra M620 delivers the power, so you can focus more on riding and less on drivetrain management.
Serious Climbing Capability: The Bafang Ultra M620's high torque output works through five automatically selected gears, giving the motor useful gearing as terrain gets steeper.
Extended Range: Start with the included 52V 17Ah battery and add a second battery when your rides demand more capacity.
Full-Suspension Control: Combine powerful motor assistance with the stability and comfort of a full-suspension fat tire platform across rough and uneven terrain.
Versatile Performance: From technical trails and loose surfaces to everyday riding, the combination of automatic gearing, high motor output, and wide tires gives you the flexibility to handle changing conditions without constantly adjusting the bike.

The Juggernaut Ultra FS Pro AUTO brings together Ultra M620 power, A510 automatic shifting, full suspension, and dual-battery capability in one platform built for riders who want substantial performance without unnecessary drivetrain management.

Choose Your Color

Choose your selected color or press Discard to return.

Frame Size

Colour Matte Black

Wheelset

Advanced Options

Packages

Battery

Range Extender Battery

This option adds an extra battery that mounts on top of the frame providing up to double the range of the stock battery.

Upgrades

Fork

Elevate your ride's comfort and control by upgrading your ebike fork, ensuring a smoother journey over any terrain.

**Upgraded front forks are incompatible with front fender included in Rack and Fender Set

Brakes

Enhance your safety and control on every ride by upgrading your eBike brakes.

***Tektro and Magura upgrades come with a brake rotor upgrade from 160mm to 203mm

Headlights

Illuminate your path to adventure with an upgraded eBike headlight, delivering superior visibility and style for night-time riding.

Dropper Seatpost

Elevate your ride with a dropper seatpost for seamless adjustments and ultimate control on any terrain.

***Adding a dropper seatpost to your eBike will increase the minimum seatpost height by approximately 75mm/3"

Biktrix A-Bars

The swept-back design of the Biktrix A Bars provides an upright riding position with multiple comfortable hand positions so you can enjoy further and more frequent rides!

Rear Rack And Fender

This rear cargo rack with a solid, integrated fender will keep you nice and dry while riding, allowing you to carry all the cargo you may want on the rear end of your bike!

Accessories

Warranty

Protect Your Bike

Secure your investment by opting for an extended warranty through the BiktrixCare+ plan.

Variant

£3,572.00

Shipping Time

Leaves within 3-4 Weeks

Juggernaut Ultra FS Pro AUTO

£3,572

Product
Overview
Features
Specs/Sizing
Reviews

£3,572

Leaves within 3-4 Weeks

1000W Mid-Drive

Motor Power

52V 17Ah 910Wh

est. 45mi Range

+5'8ft / 265lb

Max Load

Torque Sensor

Powerful Pedal Assist

25+ Point Quality

Control Checklist

85+

Miles Range

160Nm

Torque For Extreme Hills

52V 17Ah

Strong, Reliable Battery

Full Suspension. Automatic Shifting. Extended Range

The Juggernaut Ultra FS Pro AUTO combines the power of a high-performance torque-sensing mid-drive with a new 5-speed automatic internally geared hub (IGH). The automatic drivetrain handles gear changes for you, so you can focus on the trail instead of constantly managing shifts.

Add the dual-battery capability, and you have the capacity to stay out longer, with an optional range extender that works alongside the integrated battery for extended rides. Pair that with full suspension and clearance for up to 4.8" tires, and the Ultra FS Pro AUTO is built to handle demanding terrain without making the ride more complicated than it needs to be.

Automatic Shifting. Ultra Power.

The Bafang A510 5-speed automatic internally geared hub takes the guesswork out of shifting while working seamlessly with the powerful Bafang Ultra M620 mid-drive motor. The A510 automatically selects the appropriate gear as your speed and riding conditions change, keeping the M620 in a useful gearing range without requiring constant input from the rider.

Together, the two systems make the Ultra FS Pro AUTO easier to manage across changing terrain. Let the M620 deliver the power while the A510 handles the shifting—whether you're accelerating from a stop, climbing a steep hill, or transitioning back onto faster, flatter ground.

Choose Your Tires. Tune Your Ride.

Choose between 26x4" fat tires for maximum traction and stability or 27.5x3" MTB+ tires for a faster, more agile ride. The wider 26x4" tires provide a large contact patch that helps maintain grip and stability on loose dirt, sand, mud, snow, rocks, and technical terrain, while the 27.5x3" tires combine a larger diameter with a narrower profile to roll over obstacles more easily and maintain speed.

Whether you prioritize low-speed control and traction or faster, more agile handling, you can choose the tire setup that best matches where and how you ride.

Ultra Power. Greater Features.

NEW

Bafang 5 Speed Automatic Gear Hub

The Bafang A510 replaces the conventional rear derailleur and cassette with five internally contained gears that shift automatically based on wheel speed. The result is a drivetrain that handles gear changes for you. You don't need to anticipate every climb or reach for a shifter when the trail changes—just keep pedalling and let the hub select the appropriate ratio.

Bafang Ultra M620 Mid-Drive System

The Bafang M620 system features the G510 electric motor with over 1500 watts of peak power, 160Nm of torque and torque-sensing assist. Span cities, climb hills, and explore all the places you want to go with ease.

Rockshox Rear Suspension

The rear suspension sets the Ultra FS Pro apart from the rest of our lineup, making it the ultimate Full-Suspension eBike. Take on any trail with maximum comfort and control

Optional Range Extender

On top of the stock 52V 17AH 910Wh battery, add an additional 52V 17Ah Range extender battery to double your range and ride even further!

Front Suspension

The Biktrix Inverted Suspension Fork features 140mm of travel, adjustable preload and adjustable lockout

NEW

Drivetrain

The chain tensioner and half-link chain work together with the internally geared hub to maintain proper chain tension and reliable power transfer, providing smooth, consistent performance whether climbing steep hills or cruising on the flats.

Hydraulic Disk Brakes

When it’s so easy to go fast, you need strong stopping power. These dual piston hydraulic disc brakes will quickly and reliably bring you to a halt.

LCD Display

The full colour center-mounted LCD Display shows you all kinds of important information about your ride, including speed, battery life, odometer, pedal assist level and more.

Thumb Throttle & Control Pad

With just a push of the thumb, you can access all of the power the motor has to offer when needed! Give yourself an extra boost when starting from a stop or climbing up a steep hill!

Integrated Front Light

This bright LED Light is powered by the Ultra FS Pro AUTO’s battery and can be turned on or off with a button on the handlebar control pad. Need brighter light? Upgrade to the Biktrix Armageddon Light to see even brighter!

SIZE GUIDE

Let’s Get You Fitted.

6'0" Rider Height

Slide the scale for your Frame Recommendation

Based on your height, we recommended you get L | 19" for the best fit.

Not sure how to measure properly for your bike?

6'0"

Technical Specifications

Frame 6061 aluminum - 145mm frame travel	Front hub 150mm thru 36h	Seat post 31.6mm aluminum
Fork Biktrix inverted air fork w/140mm travel, lockout and preload	Front axle 15mm thru axle	Seat post clamp Qr
Headset Threadless 1-1/8 1-1/2 tapered	Rear hub Bafang a510 5 speed automatic shifting igh	Motor Bafang ultra m620
Rear axle Bolt-on	Battery sizes Total capacity of 52v 34.5ah 1794wh: 52v 17.5ah 910wh (internal battery) + up to 52v 17ah 884wh (external range extender battery)	Rear derailleur Shimano alfine chain tensioner
Rims 26" 60mm wide black with round cutouts, 27.5" 60mm wide solid black	Display Dpc-18	Cassette 30t rear sprocket
Tire sizes Chaoyang 26x4", chaoyang 27.5x3"	Lights Integrated headlight	Chain Kmc half-link chain - 125 links
Handlebar 700mm wide w/25mm rise, 31.8mm clamp	Assist type Torque + cadence	Crank set 46t chainring w/ 170mm arms
Stem 90mm solid	Assist levels 1-5	Bottom bracket Bafang isis
Grips Velo bolt on mtb grips	Throttle Thumb throttle	Brakes Biktrix dual piston hydraulic w/180mm rotors
Saddle Velo plush	Other 2-bolt kickstand	Brake levers Biktrix adjustable w/ integrated brake cutoff
Rear suspension Rockshox monarch rl w/ 51mm travel, 190mm eye-to-eye

Frame 6061 aluminum - 145mm frame travel	Front hub 150mm thru 36h
Seat post 31.6mm aluminum	Fork Biktrix inverted air fork w/140mm travel, lockout and preload
Front axle 15mm thru axle	Seat post clamp Qr
Headset Threadless 1-1/8 1-1/2 tapered	Rear hub Bafang a510 5 speed automatic shifting igh
Motor Bafang ultra m620	Rear axle Bolt-on
Battery sizes Total capacity of 52v 34.5ah 1794wh: 52v 17.5ah 910wh (internal battery) + up to 52v 17ah 884wh (external range extender battery)	Rear derailleur Shimano alfine chain tensioner
Rims 26" 60mm wide black with round cutouts, 27.5" 60mm wide solid black	Display Dpc-18
Cassette 30t rear sprocket	Tire sizes Chaoyang 26x4", chaoyang 27.5x3"
Lights Integrated headlight	Chain Kmc half-link chain - 125 links
Handlebar 700mm wide w/25mm rise, 31.8mm clamp	Assist type Torque + cadence
Crank set 46t chainring w/ 170mm arms	Stem 90mm solid
Assist levels 1-5	Bottom bracket Bafang isis
Grips Velo bolt on mtb grips	Throttle Thumb throttle
Brakes Biktrix dual piston hydraulic w/180mm rotors	Saddle Velo plush
Other 2-bolt kickstand	Brake levers Biktrix adjustable w/ integrated brake cutoff
Rear suspension Rockshox monarch rl w/ 51mm travel, 190mm eye-to-eye

Frame

6061 aluminum - 145mm frame travel

Front hub

150mm thru 36h

Seat post

31.6mm aluminum

Fork

Biktrix inverted air fork w/140mm travel, lockout and preload

Front axle

15mm thru axle

Seat post clamp

Qr

Headset

Threadless 1-1/8 1-1/2 tapered

Rear hub

Bafang a510 5 speed automatic shifting igh

Motor

Bafang ultra m620

Rear axle

Bolt-on

Battery sizes

Total capacity of 52v 34.5ah 1794wh:
52v 17.5ah 910wh (internal battery) +
up to 52v 17ah 884wh (external range extender battery)

Rear derailleur

Shimano alfine chain tensioner

Rims

26" 60mm wide black with round cutouts, 27.5" 60mm wide solid black

Display

Dpc-18

Cassette

30t rear sprocket

Tire sizes

Chaoyang 26x4", chaoyang 27.5x3"

Lights

Integrated headlight

Chain

Kmc half-link chain - 125 links

Handlebar

700mm wide w/25mm rise, 31.8mm clamp

Assist type

Torque + cadence

Crank set

46t chainring w/ 170mm arms

Stem

90mm solid

Assist levels

1-5

Bottom bracket

Bafang isis

Grips

Velo bolt on mtb grips

Throttle

Thumb throttle

Brakes

Biktrix dual piston hydraulic w/180mm rotors

Saddle

Velo plush

Other

2-bolt kickstand

Brake levers

Biktrix adjustable w/ integrated brake cutoff

Rear suspension

Rockshox monarch rl w/ 51mm travel, 190mm eye-to-eye

Size & Fittings

1	Effective Top Tube Length	580mm	22.8in
2	Seat Tube Length (Classic Bike Size)	430mm	16.9in
3	Reach	440mm	17.3in
4	Stack	540mm	21.3in
5	Chainstay Length	510mm	20.1in
6	Standover Height	730mm	28.7in
7	Head Angle	63°	-
8	Seat Angle	72°	-
9	Head Tube Length	160 mm	6.3 in
10	Fork Length	540mm	21.3in
11	Front Center	810mm	31.9in
12	BB (Bottom Bracket) Drop	40mm	1.6in
13	Fork Offset	40mm	1.6in
14	Wheelbase	1320mm	52in
15	Total Length	2030mm	79.9in
16	Max Seat Height	1040mm	40.9in
17	Min Seat Height	840mm	33.1in
18	Handlebar Height	1020mm	40.2in
19	Weight (Without Battery)	32.6kg	71.9lb

1	Effective Top Tube Length	600mm	23.6in
2	Seat Tube Length (Classic Bike Size)	480mm	18.9in
3	Reach	460mm	18.1in
4	Stack	590mm	23.2in
5	Chainstay Length	510mm	20.1in
6	Standover Height	740mm	29.1in
7	Head Angle	63°	-
8	Seat Angle	72°	-
9	Head Tube Length	160 mm	6.3 in
10	Fork Length	540mm	21.3in
11	Front Center	810mm	31.9in
12	BB (Bottom Bracket) Drop	40mm	1.6in
13	Fork Offset	40mm	1.6in
14	Wheelbase	1330mm	52.4in
15	Total Length	2040mm	80.3in
16	Max Seat Height	1080mm	42.5in
17	Min Seat Height	880mm	34.6in
18	Handlebar Height	1060mm	41.7in
19	Weight (Without Battery)	32.6kg	71.9lb

1	Effective Top Tube Length	600mm	23.6in
2	Seat Tube Length (Classic Bike Size)	520mm	20.5in
3	Reach	460mm	18.1in
4	Stack	590mm	23.2in
5	Chainstay Length	520mm	20.5in
6	Standover Height	770mm	30.3in
7	Head Angle	63°	-
8	Seat Angle	72°	-
9	Head Tube Length	160 mm	6.3 in
10	Fork Length	540mm	21.3in
11	Front Center	810mm	31.9in
12	BB (Bottom Bracket) Drop	40mm	1.6in
13	Fork Offset	40mm	1.6in
14	Wheelbase	1340mm	52.8in
15	Total Length	2060mm	81.1in
16	Max Seat Height	1120mm	44.1in
17	Min Seat Height	940mm	37in
18	Handlebar Height	1060mm	41.7in
19	Weight (Without Battery)	33.6kg	74.1lb

FAQ & Guides

Manual Juggernaut Ultra FS Pro AUTO New Owners Guide
Guide Spare Parts Finder

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How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

Juggernaut FS Pro 3

Bought 2 Juggernauts FS Pro 3's
Exceeded my expextations out of the box.
Honestly the best, fun, dialed bikes Ive ever rode, my wife is ecstatic, smiles for days, you really built a cool, fun, enjoyable e bike, more reviews to come as we ride and adventure

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

Powerful, Rugged, and Backed by Great Support

This bike has far exceeded my expectations for an electric mountain bike. Yes, it is heavy, but it is so powerful that the weight honestly does not matter much once you are riding it. It feels rugged, capable, and strong enough to handle almost anything I throw at it.
I have ridden it through everything from -30°C winter conditions to mud, snow, sand, water, and rough terrain, and it has handled it all flawlessly without hiccups. The Ultra motor has an incredible amount of torque, and the bike feels like a tank in the best way possible.
That said, there are negatives with anything. The main weak point on this bike, in my opinion, is the rear hub. The stock Quanta pawl-style hub is not ideal for the torque of the Bafang Ultra motor. Mine suddenly grenaded and left me stranded, so I strongly recommend upgrading to a star ratchet rear hub if you ride hard or use the motor’s torque aggressively.
The second thing I would recommend is not really a Biktrix design issue, but more related to the Bafang Ultra motor itself. For maximum longevity, I believe many Ultra motors come under-greased from the factory. I regreased mine with Mobilgrease 28 aircraft grease at around 500 km, and I am very glad I did because mine appeared under-greased. I believe this maintenance can greatly improve the motor’s lifespan.
If you own this bike, I also recommend having a few proper tools: a torque wrench for correct torque specs, the Ultra motor chainring removal/installation tool, crank removal tools, and basic bike tools. I relube my chain about every 100 km, and I use medium-strength Loctite on most bolts where appropriate.
Overall, I am extremely happy with the bike. Between the performance, durability, power, and Biktrix support, I honestly believe this is one of the best e-bikes you can buy. Biktrix support has been a big part of why I am giving this bike 5 out of 5 stars. Compared to other e-bike companies on the market, I believe Biktrix stands out.

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

Juggernaut FS pro 3

Great bike fun to ride and great company to deal with dealt with issues I had right away !

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

Many quality issues early on

I was super excited to get this bike but have been let down time after time. Poor wiring connections, wrong hardware provided, reflector from the one pedal fell of within the first 25 km of riding on smooth paved paths in town, there is a major lag from when you shift up until the actual shift occurs. Shifting down has been smooth though. The quality of the non-mechanical and non-electrical parts seem good with strong welds and stainless steel hardware. I would expect quality issues on a cheaper bike so I was surprised to have so many quality issues come up within the first 25 km of riding on such an expensive bike. The shifting lag being the biggest concern as it is extremely annoying when you are trying to pick up speed coming up to a hill. Not sure if I just got a dud or if these quality issues are common. Lastly, I ordered a bike with no speed limiter on it and I have not been able to get it going over 32 km/hr, even with eco mode off. Not sure if they limited me accidentally. Overall my experience is mediocre and would have rather saved a few thousand to get a cheaper bike with the expectation of having a few quality issues.

Hi there, thank you for your honest review. We apologize for the quality issues you have experienced with your Juggernaut Ultra FS Pro 3. Our team works hard to ensure that all bikes are in top condition before they are shipped out, so we are disappointed to hear about your problems. The gear sensor on the bike is designed to protect your gears from getting damaged by cutting off power during upshifts. However, we understand that the lag in shifting can be frustrating and we will pass along your feedback to Bafang, the company that manufactures the gear shift motor. As for the speed limit, it is possible that the bike was accidentally limited. We recommend contacting our customer service team for assistance with this issue. Thank you for choosing our bike and we hope to make your experience better in the future.

How was the performance of the bike?:

Poor

Excellent

How was the comforability of the ride?:

Uncomfortable

Very Comfortable

How is the build quality?:

Poor

Excellent

Great Bike!

Took out my new Juggernaut FS Pro 3 for my 1st extended ride (18 miles) and couldn’t be happier with the smoothness of the ride and power of this bike. Looking forward to more long rides on this fantastic bike!

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

1 month and still not delivered

For the Black Friday sale I was torn between 2 fat bikes and ended up going with the Juggernaut Ultra FS Pro 3. Mainly because the sale on the other bike just wasn't as desirable and their website stated "Lowest prices of the year. **no prices will not be lower later on" so I figured that was honest and went for the ultra. 1 month later and my bike still has not been delivered even though it says it ships in 6 to 7 days after placing the order. Shouldn't take more than a week to get anywhere in Canada. I reached out and it's just sitting in Edmonton waiting for warming temperatures to finish the route. In the mean time, I'm checking emails and see my second choice bike is now even cheaper than black friday even though their website stated prices would not be lower. Had they not lied I would have held out until boxing day to get a better sale. Overall not too impressed with the lack of transparency and inability to have a shipment delivered within a reasonable timeframe.

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

A Mtber review

As a long time mtber/racer my review is based on my experience..
I'm 56yrs old and have raced and rode mtb since 1991
I've had emtbs and regular fatbikes
To have a E fatbike is a next level in snow! So nice to have the assistance and flotation to get through softer trails.
The bike is heavy but not that noticeable , until you lift it into your vehicle.
Handling- good, I upgraded the headset to steepen the head angle Because it's kind of slack.
Suspension- better than I thought it would be.The front fork actually works well could, use thinner oil for the winter.
Brakes- i upgraded to 4 piston
Which took the brake safety wires off, also disconnected shift sensor (not cool when motor cuts out when shifting )
Up graded to dropper post
Changed the bars for something wider
The battery is 900wh but the range is comparable to maybe to 600wh, I get 35 to 50km offroad
I bought studded tires and have wider rims on order.
Most of these things are not a deal breaker , but just nice upgrades.
The company is very easy to contact and communicate with! For the price , I would definitely recommend this bike!

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

My bike has not arrived

My bike has not arrived

How was the performance of the bike?:

Poor

Excellent

How comfortable was the bike?:

Uncomfortable

Very Comfortable

How was the bike build?:

Poor

Excellent

Enjoying the ride

Very fun bike to ride, it has a robust felling seems to float over almost anything, also the power is awesome.

1 2 3

1000W Mid-Drive

52V 17Ah 910Wh

+5'8ft / 265lb

Torque Sensor

25+ Point Quality

Juggernaut Ultra FS Pro AUTO

Choose Battery

Upgrade Brakes

Upgrade Motor

Why BiktrixCare+?

Shipping Time

1000W Mid-Drive

52V 17Ah 910Wh

+5'8ft / 265lb

Torque Sensor

25+ Point Quality

85+

Miles Range

160Nm

Torque For Extreme Hills

52V 17Ah

Strong, Reliable Battery

Full Suspension. Automatic Shifting. Extended Range

Automatic Shifting. Ultra Power.

Choose Your Tires. Tune Your Ride.

Bafang 5 Speed Automatic Gear Hub

Bafang Ultra M620 Mid-Drive System

Rockshox Rear Suspension

Optional Range Extender

Front Suspension

Drivetrain

Hydraulic Disk Brakes

LCD Display

Thumb Throttle & Control Pad

Integrated Front Light

Technical Specifications

Frame

Front hub

Seat post

Fork

Front axle

Seat post clamp

Headset

Rear hub

Motor

Rear axle

Battery sizes

Rear derailleur

Rims

Display

Cassette

Tire sizes

Lights

Chain

Handlebar

Assist type

Crank set

Stem

Assist levels

Bottom bracket