Let’s be honest, most folding e-bikes these days are absolute units. We’re talking 60, 70, even 80+ pounds of battery-powered bulk that you’re somehow supposed to “conveniently” fold up and toss in your trunk. Yeah, right.
So when Jupiter Bike sent over their Defiant for testing, I was genuinely surprised to see it clock in at just 58 pounds. Drop the battery out, and you’re looking at a manageable 52 lbs, which is light enough that you might actually use the folding feature without calling for backup. Although, we still probably recommend you do, you know, for the safety of your back…or your ego.
But here’s where it gets interesting: Jupiter didn’t achieve this weight savings by neutering the motor. The Defiant rocks a beefy 750W rear hub (hitting 1130W at peak) paired with those chunky 20×4″ fat tires that look like they belong on a mini monster truck. It’s like they took a folder to the gym and it actually stuck with the program.
The big question: does a lighter folding e-bike with fat tires and decent power make sense, or is Jupiter trying to have their cake and eat it too? Let’s dig in and find out.
My Experience Riding The Jupiter Defiant E-Bike
Well, it’s a folder with a telescoping flat bar for the handlebars, so let’s just say this isn’t built for performance riders. But folks shopping for folders probably already know that. From a “does it fit” standpoint: sure, it fits just fine. At 5′ 11″ within their advertised range of 5′ 0″ to 6′ 2″, I had no issues getting comfortable.
To be honest, at first glance the Defiant looks small. Maybe that’s due to its lower height and slightly shorter wheelbase. But once you’re on it, the proportions make sense and feel as they should.
The Defiant ships as a Class 2 with throttle and pedal assist to 20 mph, which I soon found out it can reach very quickly. While Jupiter doesn’t list a specific torque rating aside from marketing material that reads “high-torque motor,” I’m pretty confident after testing as many e-bikes as I have that this motor is, in fact, high-torque. Getting up to max speed on flats is super fast, and hills even pushing 10% grades are no sweat for the Defiant.
After putting over 80 miles on the bike, I couldn’t resist bumping it to Class 3 despite the card that came in the shipment that read, and I quote: “Sustained riding above 20mph can damage the controller and voids the warranty.” This left a few questions unanswered, like how far or how often is considered “sustained”, is that 10 minutes or 10 hours?
Throwing caution to the wind, I held the plus and minus buttons for a few seconds to access the settings menu, which I’m happy to report was easy to navigate. Just like that, I was in Class 3 mode.
Now, I must admit, I was torn. On one hand, I was just told sustained riding over 20 mph could damage the controller and void the warranty. But man, is this little folder fun in Class 3 mode. It felt even faster, more powerful, and just plain fun. After another 20 or so miles collectively in Class 3 mode, I was relieved to see there were no issues, no errors, no smoke emitting from the bike, and no problems at all.
It led me to wonder: is this warning more for liability disclaimers? Or did they know something I don’t? I genuinely don’t know, but I do know that the Defiant is a lot more fun when I got defiant with the bike’s warnings. Should you? Well, that’s up to you to decide.
Coming down a larger hill, I was able to get the bike up to speeds cresting 30 mph. While that’s a torture test for any braking system, I found the mechanical disc brakes were up to the task of coming to a safe stop in a reasonable distance.
All in all, the bike is super fun to ride. With a little air let out of the 4-inch fat tires, you really don’t feel like you need suspension at all, even though I expected I’d miss it. Airing down is certainly underrated for rigid bike comfort. Now, if you start hitting drops and jumps, that’s likely a more uncomfortable experience, but I didn’t go crazy.
Around town it’s zippy and fun. The LED headlight gives visibility in low light or night rides, and the bike does a good job of balancing budget with beefed-up capability.
It’s also important to note: I was sent the base version of the Defiant out of a 3-model Defiant lineup. The next level up for an additional $200 (at $1,899) has a front suspension fork, and the Defiant Pro for $1,999 gives you a full-suspension setup along with several other upgrades beyond the base I was sent.
Range
Estimated Range (from Jupiter):
Real World Range Test Results:
- PAS 1: 53 miles
- PAS 5: 21 miles
Rad Power Bikes estimates the RadRunner at 55+ miles per charge with its 624 Wh battery paired to its 750W motor. To test this claim, we put the bike through two demanding range tests. First, we ran it exclusively in PAS 5, the highest pedal-assist setting, for a true stress test of its limits. We covered 28 miles before the battery depleted, which is a solid result for such aggressive use.
For the PAS 1 test, we rode in the lowest assist level to see how conservative riding would perform. We managed 46 miles before running out of battery. While this didn’t quite hit Rad’s 55+ mile claim, it’s still a respectable showing for real-world conditions. Keep in mind that range depends heavily on rider weight, terrain, wind, and how much you’re pedaling versus relying on the motor.
The battery itself is user-friendly, with a keyed lock for security and easy removal for charging. Charging takes about 6 to 7 hours with the included 2A charger, which is standard for e-bikes in this class. Overall, the RadRunner’s range is solid for most daily needs, whether you’re running errands or commuting, though heavy users tackling longer distances might need to plan charging stops or consider their riding style.
Power (Motor & Battery)
Jupiter equipped the Defiant with a 750W rear hub motor that peaks at 1,130W. While they don’t publish torque specs, the Defiant has plenty of power. The cadence sensor kicks in as soon as your pedals turn and maintains consistent power based on your PAS level. It’s predictable and straightforward, even if it’s not as refined as a torque sensor.
The bike ships as Class 2 (pedal assist and throttle to 20 mph), but you can unlock Class 3 speeds (28 mph) through the display settings. The catch? Unlocking the Defiant to class 3 speeds ‘could’ void your warranty. Jupiter warns about controller damage from sustained high-speed riding, but I tested Class 3 anyway and the bike felt totally fine. Punchy, powerful, no overheating or weird behavior.
My theory? The disclaimer is about avoiding headaches, not actual hardware limits. Between the smaller 499Wh battery (which would suffer at 28 mph) and the legal mess around Class 3 bikes right now, Jupiter’s probably just keeping things simple.
The 48V, 10.4Ah (499Wh) battery has UL 2271 certification and locks into the hinged frame with a key. It’s removable for charging or security. At 499Wh, it’s smaller than many competitors, but that keeps the bike light, which is the whole point. Battery management felt solid during testing with no cutoffs or voltage sag, even on steep climbs.
Components
The Defiant keeps things straightforward with its component selection. You’re getting a 7-speed Shimano Tourney drivetrain with a 52T chainring and 14-28T cassette. It’s entry-level stuff, but it’s also pretty par for the course in this segment and price point of e-bikes. Shifting felt reliable during testing, and the gear range handled everything from flat pavement to moderate climbs without issue.
Braking is where things get a bit disappointing. Jupiter spec’d the bike with mechanical disc brakes featuring Zoom calipers and 160mm rotors front and rear. They work, but at this price point (nearing $2,000), I’d really expect to see hydraulic disc brakes. Hydraulics would offer better modulation, require less hand strength, and provide more confident stopping power, especially at speed with those fat tires.
The dual-spring saddle deserves a shoutout. It’s genuinely comfortable and noticeably cushier than the saddles on most folding e-bikes I’ve tested. Combined with the 20×4″ fat tires, it does a solid job of smoothing out bumps.
Speaking of the bumps, there is no suspension on the Defiant. While this keeps weight down and makes cornering feel crisp and predictable, you’re relying entirely on the tires and saddle for cushioning. For riding on paved paths and packed dirt, it’s fine. Anything chunkier and you’ll start to feel it unless you air down quite a bit, which is a nice perk of having fat tires that are 4.0.
The cockpit has a 680mm alloy handlebar with a mostly flat profile, basic rubber grips, and a telescoping stem that has about 5.5 inches of height adjustment and folds down flat as a part of the bike’s folding ability. The half-twist throttle sits on the right side next to the Shimano thumb shifter. Everything feels functional, but not fancy.
Folding the Jupiter Defiant
The Defiant’s folding process is straightforward and easier than most folders, largely thanks to its lighter overall weight. The whole operation takes about 30 seconds: fold the pedals inward, collapse the telescoping stem, open the frame’s hinge latch, and fold it in half. The bike folds down to roughly 38.5″L x 21″W x 27″H, which is pretty compact for a fat tire folder.
One thing to note: if you want to remove the battery while the bike is folded, you’ll need the key that locks it into the frame. It’s a minor detail, but worth remembering if you’re planning to stash the battery separately for security or weight savings.
Like most folding e-bikes, the cables run near the hinge point. Keep an eye on them over time to make sure you’re not pinching or stressing the wiring when folding and unfolding. It’s an easy habit to develop, and it’ll save you headaches down the road.
All in all, it’s fast, easier than most folders I’ve tested, and folds up small enough to give you extra options when you’re tight on space.
Screen / User Interface / App
The display is straightforward and keeps with the overall spec of the Jupiter Defiant. It’s a decent size (about 3.5 inches) with a duo-tone LCD that shows all the basics: speed, PAS level, battery level, and odometer. Tapping the power button cycles through extra data metrics like average speed, top speed, trip meter, and time on the bike.
Want to dive into settings? Hold the plus and minus buttons on the PAS control for about 3 seconds to access the advanced menu. It’s easy to navigate and keeps things simple with just the essentials: switching between Class 2 or 3, adjusting screen brightness, and setting the auto-off timer.
There’s no app connectivity, which honestly makes sense for this bike. It’s a no-frills approach that keeps things reliable and uncomplicated.
Jupiter Defiant Model Options
Model options start with your color selection, as there are no size choices. It’s a one-size frame that fits an advertised range of 5’0″ to 6’2″, and at 5’11” I found the fit to be good. Colors range from hunter orange and grey camo, or a green and grey camo pattern. If camo is a solid “nope” for you, they have some can’t-go-wrong options like solid white or solid black.
Included accessories start with the 2A charger and a set of front-to-back fenders with a cool moto-style design that are easy to put on or remove if you don’t want to use them. There’s also a front LED headlight that you can adjust the angle on, but no tail/brake lights and no turn signals. This feels fair for a bike like this since it’s not screaming “I’m commuting here!”
But if you do plan to commute, Jupiter sells a “City Package” for $199 that includes commuter tires (likely more efficient and quieter than the all-terrain tires that ship standard), an e-bike helmet with LED lighting, a beefy lock, an LED rear tail light, and a set of handlebar-mounted rearview mirrors. Considering all that’s included, the price seems pretty solid.
If you plan to load up the Defiant, there are optional accessories like a rear cargo rack. For the outdoorsy types, Jupiter offers a cargo/utility trailer that can carry up to 220 lbs. When browsing user reviews, I saw a few hunters taking advantage of that option.
Jupiter offers three versions of the Defiant, each building on the last with smart upgrades at reasonable price jumps. The base Defiant at $1,699 gets you the core experience: 750W motor, 20×4″ fat tires, and mechanical brakes.
Step up to the Defiant PRO for $1,899 (+$200) and you gain front suspension, hydraulic brakes with a brake light, leather grips, a thumb throttle instead of twist, Shimano Altus derailleur with paddle shifter, and a MIK-compatible rear rack included.
The top-tier Defiant ST at $1,999 (+$100 more) adds full suspension front and rear, plus a larger 13.2Ah battery that pushes range to 50 miles. So, for those who want more comfort, better braking, or extended range, these tiers really do sweeten the deal without breaking the bank.
Is The Jupiter Defiant Worth Buying?
The Jupiter Defiant nails what matters most in a folding e-bike: it’s actually light enough to move around without calling for backup, yet powerful enough to make you grin when climbing hills. That’s a tough balance to strike, and Jupiter managed to pull it off while keeping the price reasonable.
Sure, the mechanical brakes could be better, and I’d love to see an integrated tail light. But for RV travelers, apartment dwellers, or anyone who needs a bike that folds up small without feeling wimpy, the Defiant delivers where it counts. The fact that it handles dirt roads and gravel paths as confidently as paved trails is just a bonus.
If you’re shopping for a folding e-bike and tired of lugging around 70+ pound monsters, the Defiant deserves a serious look. It’s not perfect, but it’s refreshingly practical in a category that often sacrifices portability for features.
Pros
- At just 52 lbs (w/out the battery), the Jupiter Defiant is one of the more portable folding e-bikes we’ve tested
- Powerful 750W motor (1130W peak) crushes hills with confidence despite not publishing the actual torque specs.
- For those who want an upgraded version, the Defiant comes in 3 pricing tires and offers really solid upgrades that are very reasonably priced.
- Dual-spring saddle is genuinely comfortable and stands out from typical folder seats
- Quick folding process takes about 30 seconds and results in a compact package at a measured 38.5″L x 22″W x 28″H
- Multiple color options including unique camo patterns and classics like Black or White.
Cons
- Mechanical disc brakes feel underwhelming at this price point—hydraulics would be a significant upgrade
Reader Interactions