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Juggernaut Ultra Duo 3 Step-Over

Sale price$3,699.00
Estimated to be shipped in 6-7 business days

The Duo Series. Ebikes for Everyone.

The Juggernaut Duo Series is all about flexibility. Hub-drive or mid-drive, step-over or step-thru, single battery or dual battery, entry-level or high-end. No matter your needs, there's probably a Duo for you.

Watch this video to see how The 3 Duo models stack up.

welcome to the big leagues.

The Ultra Duo sits at the top of the Duo range, so naturally, it boasts one of the most powerful motor systems available today. The Bafang Ultra M620 mid-drive motor is loaded with 1500W of peak power and 160Nm of torque. Pair that with the 11-speed drivetrain and you'll be nearly unstoppable.


Mid-Drive Motor

The Bafang Ultra M620 mid-drive motor features 1000 watts of power and 160Nm of torque. Span cities, climb hills, and explore all the places you want to go with ease.

LCD Display

The LCD display shows all kinds of important information about your ride including speed, battery life, range, 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. No need to pedal, just sit back and enjoy the ride.

Suspension Fork

The RST Renegade coil spring fork provides 100mm of travel with pre-load and lockout adjustability


From climbing hills to holding maximum speed on the flats, the SRAM NX 11-speed drivetrain has you covered.

Hydraulic Disk Brakes

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

Integrated Front Light

This bright LED light is powered by the bike's battery and can be turned on/off with a button on the handlebar control pad.

Optional Range Extender

Multiple range-extender battery options can expand your eBike's range all the way to 100 miles.

Rack & Fenders

These fenders will keep you and your bike clean. Need to carry some gear? Strap on the rear rack and make your way!

Technical Specifications

Size & Fittings

17" Step-Over 17" Step-Thru 19" Step-Over 19" Step-Thru

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Customer Reviews

Based on 65 reviews
mark steiner
The Freedom of a fat tire Ebike

I have owned the UD3 for several months now and riding season is just getting started. A fat tire Ebike is the way to go for anyone, because of its versatility. It can be a little difficult to load and unload due to its size and weight, but they make tilting bike racks that easily overcome that.

The bike is a joy to ride both on the road and on trails. But off-road it where it really shines. It is such a blast to ride. Provided you can stay on the bike, it will conquer any hill you can imagine.

i researched Ebikes heavily before deciding on this bike. I compared the components, specs and price to dozens of other Ebike manufacturers, as well as the reputation of the company's customer service. The process took a while but I made the right choice. Other big name bikes that have the EXACT same specs and components are selling bikes for twice what a Biktrix bike will cost you. Don't be fooled by those big names.

Also Biktrix customer service is phenomenal.

So glad I got this bike. But enough of the boring testimony from me, I gotta go for a ride!

Robert Habermehl
Biketrix Juggernaut Ultra Duo 3 First impressions

The bike is really heavy. With the standard battery it weighs in at about 80#. The chocolate brown color is more purple than brown. I’ve had 3 people tell me they like the purple color, so it’s not just me. I don’t dislike it, but it’s not what I expected.
The bike came near fully assembled, so basically, I only needed to attach the handlebars, front fender & light, and the front wheel. The rear tire was flat and had a hole in the tube from shipping, so I took it to a local shop and had it repaired. Also had them put some sealant in it. Aside from that, everything worked fine.
The frame is larger than I expected. I’m 5’9” with 30” inseam and the stand over height is almost too tall. If you're shorter than me, you'll want the step through version, or a shorter frame.
The bike rides great & I love the way it shifts through the gears. First ride I went 14 miles in eco mode PAS 5 and the battery indicated I had 82% left. The motor is reasonably quiet and has a LOT of power! It will cruise comfortably 25-26 mph in high gear. (I don't normally ride that fast...just wanted to try it out. )
I did manage to get a bunch of thorns in both tires. The rear tire with sealant was ok, but I had to take the front to the shop for repair and add sealant. The tires have good tread, but the casing seems kind of thin. I was going to go ahead and replace them, but discovered the 27.5 x 3 tire is an oddball size, and no one in Tulsa stocks that size tube or tire. They're also not listed on Biketrix’s website as a replacement part.
The handlebar grips were not very comfortable, so I replaced them with a pair of silicone grips.
I’m at about 50 miles now, and so far very pleased with bike. I do plan to have Biketrix update the program so the throttle works as a variable speed rather than just off and on, however I find I don't actually use it very much.
Stay tuned…I will update this after I get a few more miles on it.

Tyrell Hering

Juggernaut Ultra Duo 3 Step-Over

Richard Dickerson
Juggernaut Ultra Duo 3 Step-Over Review

For this review I will cover 3 things
The bike itself
The range extender
The pannier bags

The bike itself is great, although it's so heavy it feels like a tank.
I am a big guy and weigh approx 340lbs so I needed a bike that handles my weight. The Jugg Ultra duo 3 easily handles this. Once you are mounted it feels like a normal bike and handles well. I have to 4" fat tires, which are new to me, but make gravel roads a piece of cake. I do wish there was an option on the Biktrix shopping site that optionally includes something like tuff-liners to be added before the tubes are put in. Or maybe a tubeless option. As it is the tires are vunerable to flats.
Assisted peddling and a throttle are new to me, and boy it is awesome. You can feel the endorfins without being exhausted too. I like that. My biggest wish is for an option to have a bigger front crank. I find that when using the smallest gear and the high-end of my cadence the speed tops out about 20 mph. I would really like to go faster than 20 without having to peddle like crazy. I'm used to many gears from my other bikes. There isn't much I would change on the bike but this is definitely one of them.
I found I like a peddle assist of 3 being the most comfortable, spoiled already.
From my limited riding, I love the bike. It truly does open up the world to you.

The bike rack is a heavy thing, the bars seem thicker than another one I have on my recumbant, my old paniers (from a different bike) do not fit well due to the bar diameter. I did spend $100 on the offered panniers. I am sorry I bought them. The mounting depends on straps only and that is a big disappointment. You need top hooks over the bars and a lower hook for the bottom to make them solidly mounted. Hand tightened straps are never solid and will work loose. I don't like that. If I was smart I would have looked for other alternatives.

More options I wish for:
A mirror would be great.
A cell phone holder would be nice...maybe not viable due to so many variations.

Canecreek Thudbuster seat post
I spent another $150 on short-travel seat post. I really, really regret that. That is because the seat attachment assembly is a poor design. It's insane for one person to reassemble if it ever comes apart. New bikes always involve at least 100 seat adjustments to get dialed in to max comfort. Between height, tilt, forward or back rail adjustments, it takes a while to get right. Unfortunately, the assembly is finicky and the whole thing (my entire weight) depends on the robustness of a single bolt that is not big enough for the job. Plus you have to torque the crap out of it to keep it from rotating, there are no friction guards (teeth) to keep that from happening. So when going down the road at 20 or so and with a little uneven terrain, bounces will almost certainly rotate the seat tilt out of position. You can readjust in the field, but not well so your ride is compromised. (you can't really get the torque you need from a portable multi-hex tool). The normal seat post (thankfully was shipped with the bike) has a much better design. A bigger bolt and small gear teeth that mesh together to prevent tilting. Easier to slide forward or backward on the seat rails so you can position as good as can be had. So the Thudbuster is a bust for me.

Range Extender
For me, the range extender is essential. With my weight I need the extra juice for range. I don't know what my max range is but it's a lot less than 100 miles. It is a variable depending how much I use the throttle and peddle assist level. I would hope for 50 miles but I'm pretty sure it's closer to 40. That being said, I have no regrets using the throttle or higher assist. It's just way too much fun.

With the exceptions mentioned above, I have no regrets purchasing this bike and plan to put a great many miles on it.

Jeff Hennessee
Great bike

Really enjoying my first e-bike, the Juggernaut Ultra Duo 3. Very well built bike. Only have 15 miles on it but looking forward to putting many more on it. No complaints at this point.

Rick S
Great Bike - Quality and Power More Than Expected

Bike assembly was straight forward. Good customer support on a few newby questions. Exceeded expectations. Would definitely recommend

Todd Brown
Judging the Juggernaut

This is my third e bike, it has the most power and battery capacity (910 Wh extender) of the three. It also has the highest load rating of the three which was a big factor in my purchase. So far it has been exactly what I expected. I have the fat tires and I have never been that comfortable on dirt and gravel, truly remarkable. This is a great bike at any price ( I chose it over a $9000 bike). I made the right call! I’ve ordered the narrower rims for asphalt riding but I’ll be putting on the fatties for off road.

Thomas Sampson
Overall a great bike

I have had it for 1 week and have learned to adjust the settings to my liking. It wasn’t obvious, but after looking up which display I have, I was successful. Double clicking info takes several tries to get into the menu. A few problem I am working out. The first was the display lacked the small M3 bolts and was loose. The second still in process is that the second battery is not recognized since the first ride an partly through my second ride. I am awaiting tech support, but I suspect a bad on/off switch. The ride is very different the a hub drive and makes me work harder..not a bad thing for a 71 yo man. I know every problem will get worked out and I will be happy ultimately.

Dinah Tiff
Beast bike!

Bought this for my husband. He loves it and the power and long range battery life that comes with it.

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