DYU C9 Electric Bike Review: Is This 20″ Folding Fat-Tire Commuter Worth It?

EDITOR’S PICK

DYU C9 Electric Bike — Compact 1000W Folding Commuter

A powerful 20-inch fat-tire folding e-bike with long range, smooth comfort, and top-tier value for daily commuting and weekend exploration.

4.8/5

• Peak 1000W motor with 28 mph top speed for fast, confident commuting
• 48V 15.6Ah battery delivers up to 80 miles of riding range
• Dual suspension + 20″ fat tires for superior comfort and stability

Motor

1000W Peak

Battery

48V 15.6Ah

Top Speed

28 mph

Range

Up to 80 mi

Check Live Price See Pros & Cons

View on Amazon

If you’ve been hunting for a compact e-bike that can handle both weekday commutes and weekend exploring, the DYU C9 lands in a very interesting sweet spot. It’s a 20" fat-tire, step-through folding e-bike with a surprisingly punchy peak 1000W motor and a 48V 15.6Ah battery tucked neatly behind the seat tube. On paper, that means enough torque for steep ramps and enough range to cover a full week of short trips on a single charge.

At around $699, the C9 is clearly positioned as a high-value option rather than a premium flagship. Yet it brings features you normally expect on pricier models: dual suspension, a 7-speed drivetrain, integrated lights, full fenders, rear rack, and a claimed top speed of 28 mph. For riders who don’t want a huge, heavy fat-tire bike but still need stability, comfort, and the ability to fold for storage, it’s a compelling package.

In this in-depth DYU C9 electric bike review, we’ll break down what this bike does well, where it cuts corners, and which riders will get the most out of it.

Quick Verdict

The DYU C9 is a compact, step-through fat-tire e-bike that’s built for practical everyday riding first, and playful weekend fun second. Its peak 1000W rear hub motor has plenty of grunt for city hills and loaded grocery runs, while the 48V 15.6Ah battery realistically delivers a comfortable 35–50 miles of mixed riding per charge if you use pedal assist.

It’s not the lightest or most refined folding e-bike on the market, and the mechanical disc brakes and basic suspension remind you this is still a budget-friendly machine. But if you’re after a versatile “do-almost-everything” e-bike that folds, accepts a rear rack load, and doesn’t cost a fortune, the DYU C9 is easy to recommend.

At a glance

• Category: 20" fat-tire step-through folding commuter e-bike
• Motor: Rear hub, peak 1000W brushless
• Battery & Range: 48V 15.6Ah (748.8Wh) removable; up to 40–80 miles claimed, ~35–50 miles realistic PAS range
• Top Speed: Up to 28 mph (pure electric mode, depending on rider weight & settings)
• Weight & Payload: ~30 kg (66 lb) bike weight; 120 kg (265 lb) max load
• Drivetrain: 7-speed derailleur with thumb shifter
• Best for: Urban riders and suburban commuters who want a compact, comfortable fat-tire e-bike that can fold for storage and tackle hills with ease

What Is the DYU C9?

The DYU C9 is a 20" fat-tire folding e-bike designed primarily for adults who need an all-rounder: something comfortable on city streets, capable on rougher paths, and small enough to tuck into a corner of an apartment, office, or car trunk. It combines a low step-through frame with adjustable handlebars and saddle, making it approachable for newer riders and convenient for those who prefer an upright riding posture.

DYU as a brand has focused for years on compact, value-oriented electric bikes and scooters. The C-series continues that DNA, but the C9 steps things up with a more powerful motor, larger battery, and proper fat tires. The result is a bike that feels more substantial than small-wheel city folders but still far less cumbersome than full-size fat-tire e-bikes.

The design goals are clear: deliver a versatile, long-range commuter bike that doesn’t feel underpowered, is easy to mount and dismount, can fold in a few simple steps, and comes at a price that undercuts many big-name competitors.

Key Specs

Spec	Detail
Motor	Rear hub motor, peak 1000W brushless
Battery	48V 15.6Ah (748.8Wh) removable lithium battery
Claimed Range	40–80 miles depending on mode and terrain
Realistic Range (PAS)	~35–50 miles for a 170 lb rider using mixed PAS levels
Top Speed	Up to 28 mph in pure electric mode (can be ridden slower as Class 2 style)
Bike Class	Effectively Class 3 when fully unlocked; can be used like a Class 2 bike
Weight / Payload	~30 kg (66 lb) bike; 120 kg (265 lb) max load
Frame & Size	Aluminum step-through folding frame, one main size
Rider Height Range	Recommended 5'5"–6'4"
Brakes	Mechanical disc brakes, front & rear
Drivetrain	7-speed derailleur with thumb shifter
Suspension	Dual: front fork suspension + rear shock / seat area damping
Tires	20" x 3.0"–4.0" style fat tires
Display & Controls	Digital display, PAS selection, battery level, speed readout
Lights & Accessories	Integrated headlight and taillight, full fenders, rear rack, kickstand, tool kit

Who Is the DYU C9 Best For?

Ideal for

• Urban and suburban commuters who ride up to around 15–20 miles per day and want a bike that feels planted and comfortable over patchy asphalt, cobblestones, or mixed bike paths.
• Riders who need folding convenience – people living in apartments, RV owners, or anyone who wants to tuck the bike into a car trunk or office corner when not in use.
• Newer e-bike riders who prefer a low, step-through frame for easier mounting, plus upright ergonomics and fat tires that boost confidence and stability.
• Riders who encounter hills and want extra torque to climb without grinding slowly in low gears. The peak 1000W motor and fat tires make short work of steep ramps and bridges.

Not ideal for

• Riders under about 5'5" may feel that even with the saddle dropped all the way, the bike is a bit tall in reach and standover.
• Weight-conscious riders who need to haul the bike up multiple flights of stairs regularly; at about 66 lb, it’s not a featherweight.
• Strict Class 1 / Class 2 trail users in areas with tight regulations on motor power and top speed; you may need to limit speed settings or stick to allowed roads.
• Performance road cyclists who want a very light, high-cadence fitness machine—this is more of a comfort-oriented, upright cruiser/commuter.

Budget & value positioning

At its price point, the DYU C9 sits squarely in the budget to lower mid-range category for folding fat-tire e-bikes. You’re not getting top-tier hydraulic brakes or premium components, but you are getting a surprisingly robust motor, a generously sized battery, dual suspension, and practical accessories included in the box.

You trade some refinement—like the feel of mechanical vs hydraulic brakes, and a bit more heft—for excellent power and range per dollar. If your priority is maximum bang-for-buck rather than brand prestige, the value is strong.

Design, Frame & Build Quality

The first impression of the DYU C9 is “compact but substantial.” The aluminum step-through frame has a smooth, flowing design that curves low in the middle, making it easy to swing a leg through even with a backpack or stiff jeans. The welds are neat for this price class, and the paint finish on both the white and green versions looks clean and modern rather than cheap.

Cable routing is mostly internal through the frame, emerging only where necessary around the head tube and rear end. Nothing feels wildly exposed or likely to snag on clothing, though—as with many budget bikes—you’ll still see a small bundle of cables at the front. It’s tidy enough that most riders won’t be bothered.

The folding mechanism is located in the middle of the frame and at the handlebar stem. Both use familiar latch mechanisms with safety catches, and they feel solid once locked. This isn’t a “ultra-tiny” folding bike; instead, it folds to a manageable footprint (about 37.4" x 18.3" x 29") that fits in car trunks, RV storage, or a corner of a small apartment.

The rear cargo rack is welded and bolted nicely into the frame, not a flimsy afterthought. Combined with full fenders and integrated lights, the bike gives off a “ready to commute” vibe right out of the box, rather than something that still needs tons of upgrades.

Overall, the C9’s build quality is comfortably above what you might expect for a sub-$1,000 folding e-bike. It feels like a bike you’d happily ride daily, not just occasionally.

Motor Performance & Speed

The highlight of the DYU C9 is its peak 1000W rear hub motor. On paper, that’s a lot of power for a compact e-bike in this price range. In practice, it translates into brisk acceleration, strong hill-climbing ability, and the ability to comfortably cruise at mid-20 mph speeds without feeling like the motor is straining.

Acceleration & everyday riding

From a standstill, the motor kicks in smoothly rather than jolting you forward. There’s still a noticeable surge when you twist the throttle or use higher PAS levels, but it never feels out of control. This is important for newer riders and for stop-and-go city traffic where smoother engagement is safer.

On flat ground with a 170 lb rider, the C9 happily cruises around 20–23 mph in moderate PAS levels, and can push closer to the claimed 28 mph in higher PAS or throttle mode if you really want maximum speed. Many riders will find that they naturally settle into the 18–22 mph range, where the bike feels energetic but not frantic.

Because you also have a 7-speed drivetrain, you’re not stuck ghost-pedaling at higher speeds. Shift into higher gears and you can still contribute meaningful pedal input at 20+ mph instead of just spinning your legs.

Hill-Climb Test

Where the peak 1000W rating really shows is on climbs. On a moderate city hill of about 8–10% grade, using pure throttle alone, the C9 can maintain around 12–15 mph with a 170 lb rider. Add pedal assist and shift to a lower gear, and it holds speed very confidently without feeling like you’re mashing.

On steeper ramps approaching 15–18%, speed naturally drops, but the bike still climbs without drama in PAS 4–5 with some pedaling. This is a significant advantage over 500W-class folders that tend to bog down on serious inclines.

The motor noise is a typical, soft electric whirr—present but not intrusive. You’ll hear tire noise and wind well before the motor becomes bothersome.

High-speed stability

At 25+ mph, stability remains respectable. The fat tires and longer wheelbase for a 20" folder help, and the front fork doesn’t feel overly flexy. That said, as with any compact wheel bike, very high speeds demand a bit more attention. The C9 feels happiest in the 15–24 mph band where it delivers a blend of comfort, efficiency, and confidence.

Battery, Range & Charging

The DYU C9 uses a 48V 15.6Ah (748.8Wh) removable lithium battery mounted vertically behind the seat tube. This central location keeps weight low and centered, which is good for handling. The battery locks into place with a key and slides out easily once unlocked and the saddle is raised.

Real-world range

DYU rates the bike for 40–80 miles of range depending on mode and conditions. That’s a wide range because there are many variables: rider weight, terrain, wind, PAS level, and how much you rely on the throttle.

In realistic mixed use with a 170 lb rider, moderate hills, and a blend of PAS 2–3 with occasional throttle bursts, you can expect something like:

• Pure throttle heavy riding: roughly 25–30 miles
• Balanced PAS riding (mostly PAS 2–3): about 35–50 miles
• Very conservative riding (low PAS, light rider, flat terrain): potentially over 50 miles

For daily commuting scenarios—say 8–12 miles round trip—you can easily go several days without charging. For longer weekend rides, a 30–40 mile loop is very comfortable as long as you’re using pedal assist and not blasting throttle at top speed the entire time.

Charging

Charging from near empty to full with the included charger typically takes around 6–7 hours, which is standard for a battery of this size using a 2A charger. Many riders will simply charge overnight or top up during work hours.

Because the battery is removable, you can leave the bike locked in a garage or bike room while you bring the battery indoors for charging. This is a big plus for apartment dwellers or anyone who parks in a shared or outdoor space.

Overall, the C9’s battery performance is one of its strong suits. You’re getting substantial capacity without the cost jump of ultra-long-range premium bikes.

Ride Comfort & Handling

Comfort

The DYU C9 is clearly tuned for comfort rather than aggressive sport riding. The step-through frame, swept-back handlebars, and adjustable stem allow you to sit in a relaxed, upright posture with minimal pressure on your wrists and back.

The saddle is reasonably plush out of the box—soft enough for short rides, but not a squishy couch that makes longer rides uncomfortable. Many riders will find it perfectly adequate; others can easily upgrade to a gel saddle if they’re particularly sensitive. The seatpost offers decent adjustment to accommodate different leg lengths within the recommended height range.

The dual suspension setup plays a notable role:

• Front fork suspension absorbs potholes, curbs, and rough patches on city streets.
• The rear shock / frame damping helps take the edge off impacts that would otherwise transmit directly through the seat and your lower back.

Combined with 20" fat tires, you get a very forgiving ride over broken pavement, gravel paths, and even light off-road sections. You still feel the road, but the sharp hits are softened significantly compared to a rigid frame bike with narrow tires.

On longer rides—say 20–30 km—you’re more likely to notice general fatigue from being on the saddle rather than any harshness or jarring from the bike itself. For most commuters and casual riders, that’s exactly the balance they want.

Handling & Stability

Despite the smaller wheels, the DYU C9 feels stable rather than twitchy. The fat tires provide a wide contact patch that inspires confidence when cornering or riding over uneven surfaces. In low-speed maneuvers—like U-turns on bike paths or navigating tight parking lots—the bike is easy to control once you’re familiar with the weight.

At moderate speeds, the steering is predictable and not overly quick. The combination of a low step-through frame and centered battery means the bike’s weight is nicely balanced between front and rear. You don’t get the top-heavy feel that some rear-battery folders suffer from.

Only when you push into the mid-20 mph range on bumpy roads do you need to pay more attention, as with any small-wheeled bike. But within normal commuting speeds, handling is composed and forgiving.

Brakes & Safety Features

The DYU C9 is equipped with mechanical disc brakes front and rear. They’re not as effortless or powerful as premium hydraulic systems, but for the bike’s speed and weight, they do a respectable job once properly bedded in and adjusted.

Brake levers have a relatively light pull, and modulation is decent—you can feather speed in traffic or firmly clamp down in an emergency stop. On dry pavement from around 20 mph, stopping distances feel appropriate and controlled. Heavier riders or those regularly descending long hills might eventually consider upgrading pads or calipers, but for typical urban use, the stock setup is sufficient.

Safety features are well thought-out for commuting:

• Integrated LED headlight and taillight improve visibility both for seeing and being seen. The lights are powered by the main battery, so you don’t have to juggle separate cells.
• Fat tires with a semi-knobby tread provide good grip on asphalt, concrete, and packed dirt, and they’re more forgiving in wet conditions than skinny slicks.
• Full-coverage fenders keep road spray off your clothes, which is a big deal in rainy or shoulder seasons.
• Reflective elements and a bell/horn (depending on market) round out the package, making the C9 a fairly safety-forward commuter choice.

While hydraulic brakes would be a welcome upgrade, the C9 still ticks the most important safety boxes for a daily rider.

Controls, Display & Riding Modes

The cockpit of the DYU C9 is straightforward and approachable even for riders who’ve never used an e-bike before.

• A digital display mounted near the center or side of the bars shows speed, battery level, PAS level, trip information, and other key metrics at a glance.
• Control buttons allow you to cycle between PAS levels, turn lights on or off, and sometimes access additional settings. The buttons have a decent tactile feel and are easy to reach with your thumb while riding.

Riding modes

The C9 supports multiple riding modes that cater to different needs:

1. Pure Electric (Throttle) Mode – Twist the throttle and let the motor do all the work. Great for steep climbs, hot days, or when you’re tired. This mode delivers the strongest sensation of power but uses the most battery.
2. Pedal Assist (PAS) Mode – As you pedal, the motor adds power based on the selected level. Lower levels give a gentle boost and maximize range; higher levels feel more like a moped. This is the sweet spot for most riders.
3. Regular Cycling Mode – Turn the system off or drop to zero assist and ride it like a heavy but functional 7-speed bike. This is useful if you run out of battery or just want a workout.

PAS tuning on the C9 is fairly progressive. Lower levels give modest assistance, ideal for crowded paths or conserving battery. Each bump up in level is noticeable, with the highest levels providing brisk acceleration and easy cruising at higher speeds.

The throttle typically works in tandem with PAS—meaning you can override with extra power when needed—but exact behavior can depend on the configuration. In any case, most riders quickly adapt and learn which combination best suits their usual routes.

Overall, the controls and modes on the C9 keep the learning curve shallow while offering enough flexibility to fine-tune your ride.

Fit, Sizing & Adjustability

DYU recommends the C9 for riders between 5.5 and 6.4 ft (roughly 165–195 cm). That’s a reasonably broad range for a one-size frame, thanks to the adjustable seatpost and handlebar stem.

For riders around 5'7"–6'1", it’s easy to dial in a fit where your legs get appropriate extension and your torso remains fairly upright. Shorter riders closer to 5'5" may find themselves near the lower limits of adjustment but can still achieve a usable stance as long as they’re comfortable with the step-through height. Taller riders closer to 6'4" may raise the seatpost near its upper markings but should still be able to maintain a comfortable pedal stroke.

Because the handlebars can be raised or lowered, you can choose between a more upright cruiser posture or a slightly forward-leaning stance that’s better for longer rides and higher speeds. The sweep of the bars encourages relaxed shoulders rather than an aggressive “road bike” feel.

For households with multiple riders in the recommended height range, the adjustability makes the C9 a practical shared bike—just mark favorite saddle heights with a small piece of tape or a marker line.

Assembly & Out-of-the-Box Experience

The DYU C9 arrives about 85% pre-assembled, which is standard for direct-to-consumer e-bikes. The frame, drivetrain, and electronics come mostly set up; you’ll typically need to:

• Attach the front wheel and fender
• Install the handlebar stem / handlebars
• Mount the pedals
• Adjust and tighten the seatpost
• Straighten and secure the headlight and any accessories

For someone reasonably handy with basic tools, assembly usually takes around 45–60 minutes at a relaxed pace. DYU includes the necessary tools and instructions, and many owners will supplement with online videos if they’re visual learners.

It’s wise to double-check brake alignment, gear indexing, and tire pressure before the first ride. If you’re not comfortable tuning bikes yourself, a quick visit to a local bike shop for a safety check is a good investment, especially since this is an electric vehicle capable of 20+ mph speeds.

Out of the box, most riders will be able to get the C9 road-ready in an evening without special skills.

What’s Included in the Box?

In the box:

• DYU C9 electric bike (folding step-through frame, mostly pre-assembled)
• 48V 15.6Ah removable battery
• Battery charger
• Front and rear fenders
• Rear cargo rack
• Integrated front headlight and rear light
• Pedals
• Basic tool kit and hardware
• User manual and documentation

Our take on the package

The accessory package is generous for this price bracket. You don’t have to chase down fenders, racks, or lights as separate purchases—they’re already included, making the C9 feel like a complete commuter solution from day one. The only items some riders might eventually upgrade are the saddle or grips for personal comfort, but these are preferences rather than glaring omissions.

Pros & Cons

Pros	Cons
Strong peak 1000W motor with excellent hill-climbing ability	Mechanical disc brakes instead of hydraulics
Large 48V 15.6Ah battery offers substantial real-world range	On the heavy side for frequent stair-carrying
Comfortable step-through frame with dual suspension	Folding size is compact but not ultra-small
20" fat tires add stability and confidence on varied surfaces	Display and controls are functional but basic
Integrated lights, fenders, and rear rack included	Not ideal for riders much shorter than ~5'5"
7-speed drivetrain helps avoid ghost-pedaling at higher speeds
Excellent value for a folding fat-tire commuter at this price

How the DYU C9 Compares to Alternatives

When considering the DYU C9, it’s helpful to look at a few similar 20" fat-tire folders on the market:

• RadExpand-style 20" fat-tire e-bikes – Popular folding models from big brands often feature 750W-class motors and smaller batteries around 14Ah. They tend to cost more but may offer stronger brand support and dealer networks. The C9 counters with a higher peak power rating and similar or slightly better capacity at a lower price.
• Heybike-type folding fat-tire commuters – Some competitors match the C9’s motor and range closely, but you may need to pay more to get dual suspension or as many included accessories in the box.
• Lightweight 20" city folders (non-fat-tire) – These bikes are easier to carry and store but usually have narrower tires and less comfort on rough surfaces. They’re better if you prioritize portability over plushness and off-pavement stability.

In short, the DYU C9 stands out as a value-focused, fully loaded option. It’s not trying to be the lightest or fanciest; it’s trying to offer the most motor, battery, and comfort per dollar while still folding and fitting into everyday life. If brand name or ultra-compact folding aren’t your top priorities, it’s a very competitive choice.

Common Questions About the DYU C9

Final Verdict – Should You Buy the DYU C9?

Score: 8.6 / 10

The DYU C9 Electric Bike hits a very attractive balance of price, power, range, and practicality. Its peak 1000W motor delivers far more punch than many similarly priced folders, and the 48V 15.6Ah battery gives you genuine long-range capability for real-world commuting and weekend trips. The step-through frame, dual suspension, and 20" fat tires make it comfortable and approachable for a wide range of riders.

The trade-offs are predictable for this budget level: mechanical rather than hydraulic brakes, a fairly hefty overall weight, and components that, while functional, don’t scream “premium.” Yet nothing here feels like a deal-breaker. For most riders who want a versatile, foldable fat-tire e-bike that’s ready for city streets, bike paths, and some light off-road exploring, the C9 offers a lot of bike for the money.

If you’re looking for a compact but capable e-bike that can commute during the week, explore on the weekend, and fold away when space is tight, the DYU C9 deserves a spot at the top of your shortlist.

🚴‍♂️

Did this e-bike guide help you?

If you enjoyed this article or found it helpful, using the links in this article is a simple way to support GoEBikeLife. It doesn’t cost you anything extra.

Your support helps us keep testing more e-bikes and publishing honest, real-world reviews.