DYU D3F

Today, we are looking at a mini electric bike that is small in size and relatively light on your wallet. It’s the DYU D3F Mini Folding Electric Bike. At about half the cost of a full-size budget e-bike, it could be considered affordable by some. I’m skeptical as to whether this little thing can live up to the claims made by DYU, which include:

• A pedal assist range of 30-37 miles.
• The ability to climb a 15° grade.

But as the saying goes, “Don’t judge a package by its size”. So I won’t be going easy on this little e-bike! It’s time to put the D3F through its paces by running it through all of our usual tests. Let’s find out just how many miles we can squeeze out of this little guy.

What Is the DYU D3F?

The ‘Mini Electric Folding Bike’ label is accurate for the DYU D3F. It’s small, with 14″ tires and a handlebar that sits at waist level for my 6’0″ frame. The “folding” function does not refer to the frame, as we see with other folders. Rather, the handlebars fold at the bike’s headset, allowing the bike to have a diminished profile. The pedals also fold, flat against the bike’s cranks. It weighs about 38 lb and packs a 36V 10Ah integrated battery that cannot be removed. So you’re always going to be bringing it indoors with the attached carry handle to charge it.

The bike looks a little odd, and the first ride has a similar vibe, switching between childish fun and the slightly awkward feeling that accompanies riding an undersized bike. At least for me, at 6’0”, the fit is less than ideal, yet somehow manageable for short periods. If the DYU D3F can really go 30+ miles, the range test is going to be a tough one! So in a nutshell, the D3F seems like a great toy e-bike. Plus, for short-range or mixed commuting with a lower weight and general profile, its mobility is increased. So, is it a toy? Or could it be of some use to budget-minded commuters? Let’s take a look at the pros and cons and find out more.

Pros

Relatively Compact Size

The D3F is small and relatively light, at 38 lb. While it is not the smallest or lightest of the mini e-bikes available, this is its main plus. It will squeeze into spaces that other bikes simply won’t, like the boot of a car. Plus, with its attached carry handle and small size, it can be carried and easily moved around in tighter urban spaces. The D3F folds into an unwieldy package that remains heavy to lift, at almost 40 lb. However, the ability to streamline its overall shape and to condense its size is a big plus, if you have limited storage space available to stash your bike (when you’re not riding it).

Nimble to Maneuver

The bike’s small size is also a benefit when you are riding in the tight confines of an urban environment. The small wheels make for a very small turning radius, allowing the D3F to corner on a dime. And while this proves a little sketchy at speed, it’s a bonus when performing low-velocity maneuvers. So, size is the largest benefit of this little bike, both when riding and storing it.

Impressive Range

When it came to the range test, I was impressed with this little bike! Despite the fact that the battery cannot be removed, it is large. A 10Ah battery, operating a small 250W motor, could be considered oversized for this small bike. It was able to power the unit for over 22 miles using mainly throttle. Now, this route included only mellow grades, but the bike made it up them with some additional pedal power. The range test was slow, taking over two hours to reach the 22-mile maximum. But even so, the ability to throttle yourself for over 20 miles on this little bike, really made it seem like a capable mini commuter. So the bike earns some serious points with its maximum battery range.

Cons

Battery Is Not Removable

The battery is integrated into the frame. This means that you will not be able to remove it to charge or replace it. You also will not have the option to bring a second battery along for a ride. The entire unit will need to be replaced, should it suffer an issue. This is inconvenient and not as practical as having a removable battery.

Cannot Climb Hills

The unit is paired with a 250W battery that is practically useless on anything more than a gentle slope. Go beyond a slight incline and the bike just has no power. You are better off walking up most hills. I don’t know where they get the claim that it will climb a 15° grade, but it would never make it. Short gentle hills and flat ground are all this bike is made for.

Twitchy Steering

The combination of a long stem, straight narrow handlebars, and a small 14” wheelset makes this bike very twitchy to steer, with small movements resulting in big responses. These small wheels are not very comfortable at speed. It feels like you’re riding a shrunken little unit, and I was thankful the thing tops out at 15.5 mph. At speed, I prefer a mini e-bike with a larger wheelset. So be careful riding the DYU D3F! Overall, the handling lends itself more to being a child’s toy than a true e-bike.

Reversed Brake Levers

On the test bike we received, the right-hand brake lever operated the front brake, while the left-hand lever operated the rear brake. This is opposite to the standard setup required of manufacturers of new bikes and e-bikes for the North American market — and it made for a confusing first stop. It’s a definite downside on a bike with such a small wheelbase, and could lead to a nasty spill if you stopped suddenly at that top speed of 15 mph, with only the front brake.

What Does It Do Best?

The bike uses size to its advantage and offers a lightweight package that is easy on the wallet. If you’re seeking a good toy for a young rider, this would be it. It could also be the right pick if you have no access to a car rack and you’re after a very light-duty commuter that can be thrown in the back of a compact car.

Who Should Buy This Bike?

The DYU D3F is a choice for budget-minded riders looking for an e-bike that will fit into spaces other bikes would not. I can only see people purchasing this bike if they specifically need to be able to fold down and fit their e-bike inside the boot of a car. When looking at the available options, this is probably the most affordable e-bike on the market, and it comes with the same downsides other budget bikes do.

Reasons to Look Elsewhere?

The DYU D3F is tiny! Larger riders will not be comfortable. I also have serious doubts regarding its ability to perform practically as a commuter. Unless you live in a small flat urban area and need to fit into tight spots, other bikes may offer better overall value. Even among mini and folding e-bikes, the best part of the DYU D3F is the price tag, so buy accordingly.

Conclusion

The DYU D3F was a tiny bit disappointing, but with everything about this bike being pretty tiny, this was hardly a surprise. If you have a short commute and are looking for an e-bike to match, it might make a good fit. Otherwise, the best reason to buy this e-bike is as a gift for a smaller or younger rider. As a youth, I would have loved one of these to ride around the neighborhood. Check out the full specs below.

Specs

Electric Bike Class:
Class 2
Warranty:
Frame: 1 year
Return policy: 14 days
Model Year:
2021
Total Weight:
37.5 lb
Motor Brand:
Unknown
Motor Type:
Brushless
Rear hub
Motor Nominal Output:
250W
Maximum Torque:
10Nm
Battery:
36V 10Ah
Range [Claimed]:
Throttle-only: 15-35 miles
Pedal assist: 30-37 miles
Range [Tested]:
Throttle-only: 22 Miles
Maximum Assist Speed:
15.5 mph
Throttle:
Half twist
Pedal Assist:
Yes
1 assist level
Controller:
36V
Brand: Unknown
Charger:
42V 1.5A
Charge Time [Claimed]:
5-6 hours
Display:
4 LED
Battery powered
Frame:
Steel
Fork:
Steel
Brand: Unbranded
Suspension: None
Brake Levers:
Aluminum
Mechanical
Brand: Unbranded
Brake Calipers:
Mechanical
Brand: Unbranded
Brake Rotors:
160mm
Chain:
Brand: Unbranded
Derailleur:
N/A
Shifter:
N/A
Freewheel:
Single speed
Rims:
Aluminum
5-spoke
Spokes:
N/A
Tires:
14” × 2.125”
Fenders:
Plastic
Front and rear
Lights:
Front: Integrated LED
Rear: Battery-operated, removable
Grips:
Integrated
Plastic
Handlebar:
480mm
Straight
Kickstand:
Single-sided
Mini
Pedals:
Plastic
Folding
Maximum Payload (cargo and rider):
265 lb

Frame and Geometry

The bike is a little strange, with its long stem and short standover height. It was not built for tall people, and at 6’0”, I felt cramped. Because I struggled to find adequate legroom, pedaling was uncomfortable, even with the seatpost fully extended. The long stem and tiny tires also make for a jittery steering experience. In general, the bike feels just how it looks; small and a little odd. The frame is pretty robust. At 38 lb, the bike is compact. A built-in handle provides a convenient and easy carrying position.

Motor

The little 250W motor is trying hard, but with only 10Nm of torque, it’s only capable of so much. On gentle terrain the motor is adequately supportive. The throttle kicks in with a slight delay and will gradually get you to the bike’s top speed. Pedal assist offers significantly more pep, as you add to the motor’s output with your own leg power. With only a single assist setting and a single gear to back it up, the bike is limited, and its abilities to climb hills are questionable at best. It’s only really suited to flat ground, and the motor is easily the smallest and least powerful we have ridden.

Cockpit and Control

The cockpit and controls are very minimal. Only two buttons control the unit. Four LED lights indicate on/off status and battery level. The straight 480 mm bars are easily removed with a clamp. They are fitted with uncomfortable, integrated plastic grips and a half-twist throttle. Generic aluminum mechanical levers and a simple bell complete the cockpit. You turn the bike on or off with a single click, and on the opposite side, a cruise control button will keep you at speed while moving. Long-pressing this cruise control button for over three seconds activates and deactivates the front light. The battery is shown as four LED lights.

Battery

The integrated 36V 10Ah battery is not removable, which is a major drawback. The battery is larger than some of the other mini bikes we have tested, and with a smaller motor it makes for a longer range. The overall range was impressive, with the D3F carrying you for over 20 miles on throttle alone!

Range Test:

• Distance: 22.03 miles
• Time:1 hour 47 minutes
• Elevation:728 feet

Charger, Battery Removal, Keys

The charger plugs into the integrated battery low down on the unit. It’s covered with a rubber plug and can be tough to locate at first. The bike must be brought to an electrical outlet to charge it, as the battery cannot be removed. That’s a big negative! Luckily, the bike is small enough to bring inside, but this is still a drawback. There is no key and no way to remove the battery. This is a rarity among modern e-bikes, which usually sport both features.

Drivetrain

The bike has a single-speed drivetrain and a short crankset. It’s a tough pedal at low speeds, and at high speeds it has an uncomfortably fast cadence. The single gear does not climb well, so the drivetrain really leaves a lot to be desired.

Brakes

With a basic mechanical brake set and 160mm calipers, front and back, the brake components appear oversized and robust on this small unit. They stop the bike quickly, which isn’t difficult with such small wheels and a top speed of 15 mph. Our unit arrived set up with the right brake lever controlling the front brake and the left lever activating the rear brake. This is reversed from the standard North American setup. Very confusing! And with a short wheelbase, this could lead to some nasty results, so watch out!

Wheels, Tires

Small 14” wheels with relatively skinny 14” × 2.125” tires are only suited to pavement and hard-packed surfaces. They sink quickly on loose ground and are sketchy at speed (on anything but pavement). The small wheels are also quick to wander with only a slight movement of the bars. I did not enjoy the small wheel size, except when maneuvering in a very small space.

Kickstand

The D3F sports a standard single-sided kickstand that’s mini-sized, just like the rest of the bike. It operated fine, just in mini form.

Contact Points

There is not much to be said about the contact points. The plastic grips are hard and uncomfortable but function fine. They appear to be built-in, so there’s no swapping these out.

The seat is adequately padded, with an unusual shape that slopes toward its center. The seat post is short for my 6’0″ frame and caused me some discomfort while pedaling.

The plastic pedals flip up to reduce the bike’s profile and size. They are functional but basic.