Fat-Tire Step-Through Electric City Bike
HKM-0893139 Electric Fat Tire City Bike
The HKM-0893139 combines a 250 W rear hub motor with a massive 52 V 60 Ah lithium pack (3,120 Wh) in a step-through steel frame built for urban mobility. The 20 x 4.0 in fat tires roll over potholes, cobblestones, and gravel paths with grip and comfort. Hydraulic disc brakes front and rear, a 7-speed drivetrain, integrated LED lighting with brake activation, a backlit LCD display, and Bluetooth app connectivity round out a bike that handles daily commutes, errand runs, and weekend path rides with ease.
250 W Motor (100 Nm+ Torque)52 V 60 Ah / 3120 Wh Pack20 mph Top Speed37+ mi Range20 x 4.0 in Fat TiresHydraulic Disc BrakesBluetooth App Connected300 lb Load Capacity
Motor
250 W
Rear hub, 100 Nm+ torque
Battery
52 V 60 Ah
3120 Wh removable lithium
Top Speed
20 mph
32 km/h, Class 2 assist limit
Range
37+ mi
60+ km, varies with assist
Tires
20 x 4.0 in
Fat tread, puncture-resistant
Load Capacity
300 lb
136 kg rider plus cargo
Overview
The HKM-0893139 is built around a low-step high-tensile steel frame designed for easy mounting and dismounting in city traffic. The dropped top tube lets riders flat-foot at stoplights without swinging a leg over a high bar. The frame is rated for a combined rider-and-cargo load of 300 lb — enough for an adult rider plus a backpack, panniers, or groceries on the rear rack.
At the heart of the drive system is a 250 W rear hub motor tuned for urban responsiveness. Despite its modest nominal rating, the motor delivers over 100 Nm (73.8 lb-ft) of torque — enough to accelerate from standstill quickly and flatten moderate inclines up to 15 degrees without straining. A sinusoidal controller keeps power delivery smooth and quiet so you hear city sounds around you.
The 52 V 60 Ah lithium pack is one of the largest capacity packs found on any e-bike in its class at roughly 3,120 Wh. For context, most commuter e-bikes ship with 400-600 Wh — this pack carries five to eight times that energy budget. That capacity translates to 37+ miles of mixed-assist riding per charge, with potential for considerably more under conservative use. The pack uses automotive-grade 21700 cells managed by an intelligent BMS that monitors cell balance, temperature, and short-circuit protection across hundreds of charge cycles.
Comfort features match the drivetrain capability. The 20 x 4.0 in CST fat tires run at 20-30 PSI, acting as natural suspension that absorbs road imperfections before they reach the rider. Dual-piston hydraulic disc brakes with 180 mm front and 160 mm rear rotors provide fade-resistant stopping power in wet or dry conditions. An integrated brake light activates automatically when either lever is pulled, adding visibility from behind in traffic.
Key Features
250 W Rear Hub Motor (100 Nm+ Torque)
A brushless rear hub motor delivers over 100 Nm of peak torque despite its 250 W nominal rating. The sinusoidal controller produces smooth, near-silent power delivery that feels like a natural extension of your pedaling effort — flattening hills and making every start effortless.
52 V 60 Ah Lithium Pack (3,120 Wh)
One of the largest e-bike battery packs in its class at 3,120 Wh total energy. Automotive-grade 21700 cells deliver consistent voltage even below 20 percent charge. The intelligent BMS actively balances cells during charge and discharge, extending pack life well beyond 800 cycles while retaining 80 percent capacity.
Front Suspension Fork
A suspension front fork absorbs potholes, curb drops, and road cracks before they reach the handlebars. Combined with the low-pressure fat tires acting as secondary suspension, the ride stays comfortable across broken pavement, cobblestones, and gravel shortcuts.
Hydraulic Disc Brakes With Brake Light
Dual-piston hydraulic calipers act on 180 mm front and 160 mm rear rotors. The mineral-oil hydraulic system provides consistent lever feel in wet or dry conditions. An integrated brake light activates whenever either lever is pulled for visibility.
7-Speed Derailleur Drivetrain
A reliable 7-speed rear derailleur with indexed shifter gives usable pedaling cadence from walking pace up to cruising speed. The wide gear range works in harmony with the electric assist, letting you find ideal cadence whether climbing a bridge or cruising a greenway.
20 x 4.0 in Puncture-Resistant Fat Tires
CST fat tires with reflective sidewall stripes run at 20-30 PSI for a large contact patch that grips wet pavement, loose gravel, and light snow alike. Puncture-resistant casing reduces flat risk on urban debris and glass-strewn bike lanes.
80-Lux LED Headlight and Programmable Horn
A bright 80-lux LED headlight illuminates the path ahead with a wide, even beam. A programmable horn offers friendly alerts to pedestrians. Both are powered by the main battery with no separate batteries required.
Bluetooth 5.0 and Smart Display
Integrated Bluetooth links the bike to a companion smartphone app (iOS and Android) for real-time speed, distance, battery health, trip logging, and firmware updates. A backlit LCD on the handlebar shows ride data at a glance with auto-dimming.
Full Specifications
Model
HKM-0893139 | Electric Fat Tire City Bike
Frame Material
High-tensile steel, step-through geometry, internal cable routing
Motor
250 W rear-hub brushless DC, peak torque 100+ Nm
System Voltage
52 V DC
Battery
52 V 60 Ah lithium-ion (3,120 Wh), removable, BMS protected
Charger
3 A smart charger, 100-240 V input
Charging Time
6-7 hours from empty
Battery Cycle Life
Approximately 800+ charge cycles to 80 percent capacity
Top Speed
20 mph (32 km/h) motor assist limit
Range per Charge
37+ mi (60+ km) under typical mixed assist mode
Climbing Grade
Up to approximately 15 degrees with a solo rider
Peak Torque
100+ N.m (73.8+ lb-ft)
Drivetrain
7-speed rear derailleur, indexed shifter
Brakes
Hydraulic disc, 180 mm front / 160 mm rear rotors, dual-piston calipers
Suspension
Front suspension fork
Tires
20 x 4.0 in fat tires, puncture-resistant casing, reflective sidewalls
Wheels
20 in alloy rims, stainless spokes
Saddle
Padded ergonomic saddle with adjustable height
Display
Backlit color LCD with auto-dimming: speed, battery, assist, odometer
Throttle
Twist-grip throttle plus 5 pedal-assist levels and walk-assist mode
Lighting
80-lux LED headlight, integrated brake-activated tail-light, programmable horn
Load Capacity
300 lb (136 kg) rider plus cargo
Bike Weight
Approximately 66 lb (30 kg) including battery
Recommended Rider Height
5 ft 2 in to 6 ft 4 in (157-193 cm)
Certifications
CE, RoHS; battery cells UN38.3 tested
Battery, Range, and Charging
The 52 V 60 Ah pack stores approximately 3,120 Wh of energy — one of the largest capacities available on any e-bike in this category. Most commuter e-bikes ship with 400-600 Wh; this pack carries five to eight times that amount. That extraordinary headroom is what enables multi-day riding between charges and eliminates range anxiety for daily commuters regardless of how far the round trip stretches.
Real-world range depends primarily on assist level and terrain. Under typical mixed pedal-assist conditions on level ground, expect 37+ miles (60+ km) per charge. Conservative eco-mode riding can extend that further. Throttle-only operation at higher speeds reduces range compared with pedal-assist. Cold weather below 40 F (4 C) temporarily reduces available capacity by 10-20 percent; it recovers once the pack warms to room temperature.
Tip: Store the pack between 30 and 70 percent charge if the bike will sit unused for more than a month, and top it up every 4-6 weeks. Charging indoors at room temperature extends usable pack life considerably compared with charging outdoors or in an unheated garage.
The pack unlocks with the supplied key and lifts out for convenient indoor charging at home, the office, or anywhere with a standard outlet. Two keys are included. Charging with the pack installed works equally well through the accessible frame-side port.
Daily Use & Care
- Set tire pressure between 20-30 PSI depending on load and surface: higher for pavement commuting, lower for gravel or dirt paths.
- Wipe down the frame after riding in rain or on wet roads. The steel frame resists corrosion but benefits from regular cleaning in humid or coastal environments.
- Check axle nuts and stem bolts before the first ride of each week. Hub-motor torque works fasteners loose faster than conventional bikes.
- Lubricate the chain every 100-150 mi or after riding through water or dusty conditions.
- Inspect hydraulic brake pad thickness monthly. Replace when friction material is under 1 mm.
- Charge indoors at room temperature. Unplug once the indicator shows full.
- Keep display and charge port covers closed when parked outside. Electrical components are IPX5-rated against rain and splashes.
What's in the Box
- 1 x HKM-0893139 electric fat tire city bike, approximately 85 percent pre-assembled
- 1 x 52 V 60 Ah removable lithium battery pack
- 1 x 3 A smart charger with 100-240 V input
- 2 x Battery keys
- 1 x Toolkit with hex wrenches and pedal spanner
- 1 x Pair of folding pedals
- 1 x Rear rack (pre-installed)
- 1 x User manual and assembly guide
Frequently Asked Questions
How much assembly is required?+
The bike ships roughly 85 percent assembled. Remaining steps include fitting the front wheel, straightening the handlebar, installing pedals and saddle, and checking brake alignment. Budget 30-45 minutes with the supplied tools.
What real-world range should I plan for?+
Plan for 37+ miles under typical mixed assist mode on level ground. Actual range varies with rider weight, terrain, assist level, tire pressure, and temperature. Aggressive throttle use reduces range; conservative pedaling extends it.
How long does charging take?+
About 6-7 hours from fully empty with the included 3 A charger. Partial top-ups take less time. There is no need to run the pack down before recharging — charge whenever convenient.
Does the app require a subscription?+
No. The companion smartphone app is free to download and use. All core features including ride tracking, diagnostics, and firmware updates are included without recurring fees.
Can I ride in the rain?+
Yes. Electrical components are IPX5 water-resistant against rain and splashes. Avoid submerging the bike or directing high-pressure washers at the motor or battery housing.
Is the bike suitable for off-road trails?+
The fat tires and robust frame handle gravel, dirt paths, and moderate trails comfortably. However, this bike is optimized for urban and suburban environments; extreme downhill or technical singletrack is not recommended.
Can I pedal if the battery runs out?+
Yes. The 7-speed drivetrain works independently of the motor. At approximately 66 lb the bike is heavy but can be pedaled unassisted on flat ground in an emergency.
Is the battery removable for indoor charging?+
Yes. It unlocks with the supplied key and lifts out of the frame. You can also charge it in place through the frame-side charge port.
Service & Policies
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Every order ships free. Handling Time: 0-1 business days (Monday to Friday). Transit Time: 2-5 business days (Monday to Friday). A tracking number is emailed as soon as the parcel leaves our warehouse.
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Your purchase is protected for 180 days from the delivery date against manufacturing defects and damage in transit. If something arrives wrong, we make it right.
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Not completely satisfied? Request a return within 30 days of delivery for a full refund. We keep the process simple and hassle-free.
24 Months Warranty Service
The product is covered by a 24-month warranty from the delivery date against manufacturing defects. Coverage includes parts and labor; normal-wear items are excluded.
CERoHSUN38.3 Battery3120 Wh PackHydraulic BrakesFat TiresBluetooth Connected
Why Choose the HKM-0893139
Massive Battery, Zero Range Anxiety
At 3,120 Wh, the 52 V 60 Ah pack carries more energy than most e-bikes on the market. Multi-day commutes between charges become routine rather than exceptional — no planning your week around finding a charging outlet.
Fat Tires for All Surfaces
The 20 x 4.0 in tires grip wet pavement, loose gravel, cobblestones, and even light snow with equal confidence. Low pressure capability turns the tires into passive suspension that absorbs what the frame cannot.
Connected Intelligence
Bluetooth 5.0 links to a smartphone app for real-time ride data, battery health monitoring, trip logging, and over-the-air firmware updates. The backlit LCD keeps essential info visible day or night without reaching for your phone.
Whisper-Quiet Urban Riding
The sinusoidal motor controller produces smooth, near-silent power delivery. You hear city sounds around you — not motor whine. Reduced acoustic fatigue makes longer commutes and errand runs noticeably more pleasant.
Step-Through Accessibility
The dropped top tube eliminates the leg-over mount. Riders in work clothes, riders with limited mobility, and anyone stopping frequently at traffic lights can swing a leg through and flat-foot at every stop without contortion.
Built for Daily Urban Use
IPX5-rated electrical connectors, a lockable battery compartment, hydraulic brakes that resist corrosion, and a steel frame built for repeated mounting and dismounting — every detail targets riders who use their bike every day, not just on weekends.
Controls & Indicators
Power Button
Located on the battery pack; hold to switch the system on and off
Mode Buttons
Up and down buttons on the display cycle through 5 pedal-assist levels plus zero assist and walk mode
Twist Throttle
Right-hand grip; proportional response where regulations permit
Speedometer
Live speed readout in mph on the backlit color LCD
Battery Gauge
Percentage readout and segmented bar on the color LCD display
Light Switch
Long-press the up button to toggle the LED headlight, tail-light, and horn
Shifter
Right-hand index shifter for the 7-speed rear derailleur
Pre-Ride Safety Checklist
- Check tire pressure and set it for your route: 25-30 PSI for paved commuting, 20-25 PSI for mixed surfaces, 15-20 PSI for gravel or dirt.
- Squeeze both brake levers. They should firm up well before the grip with no sponginess indicating air in the hydraulic line.
- Confirm the battery is seated, locked, and shows expected state of charge on the display.
- Spin both wheels and check that rims run true and nothing rubs the brake pads or frame.
- Verify quick-release levers and axle nuts are tight, and the headset has no play when you rock the bike with the front brake applied.
- Test the throttle at walking pace in a clear area before riding in traffic.
- Switch on the headlight, tail-light, and confirm horn function if riding near dusk or in busy areas.
Quick Troubleshooting
The motor does not engage when I twist the throttle.+
Confirm the display is on and shows charge, the battery is locked into place, and both brake levers are fully released — brake cut-off sensors disable the motor while a lever is pulled. If an error code appears, note it and contact support.
Range dropped noticeably compared with when it was new.+
Check tire pressure first — a soft fat tire on pavement is the most common cause. Then consider temperature effects. If range is down more than 30 percent year-round after many cycles, the pack may be approaching end of service life.
The brakes feel spongy at the lever.+
Air in the hydraulic line or fluid degradation. Stop riding and have the system bled with fresh fluid. Plan a fluid bleed every 2 years or when lever feel becomes spongy.
The chain skips under hard pedaling.+
Derailleur indexing is likely out of adjustment, or the chain and cassette are worn. Adjust the barrel adjuster a quarter turn at a time. If skipping persists only in small cogs, replace the cassette and chain together.
The Bluetooth app will not connect.+
Confirm Bluetooth is enabled on your phone and the bike display is powered on. Move within range (typically 10 meters / 30 feet). If connection fails repeatedly, check for firmware updates in the app settings or restart both devices.
The display shows an error code and the bike will not move.+
Power off, wait 30 seconds, and switch back on. If the code returns, note the exact code and conditions, then contact support — codes map to specific faults in the controller, motor, or throttle circuits.
Certifications & Standards
The HKM-0893139 is produced in a facility operating under an ISO 9001 quality management system. The battery cells and assembled pack carry test documentation normally required for lithium-ion transport and sale.
- CE - European Conformity marking covering the electrical assembly.
- RoHS - Restriction of Hazardous Substances compliance for the electronics.
- UN38.3 - Battery transport safety testing, required for lithium-ion shipping by air, sea, and road.
- MSDS - Material Safety Data Sheet available for the battery pack on request.
- ISO 9001 - Quality management system certification held by the manufacturing facility.
Important Safety Notes
This is an electric bicycle with a 250 W motor capable of 20 mph assisted speed. Read the manual fully before the first ride and practice throttle control in an open area until the response feels predictable.
- Wear a helmet on every ride. A certified bicycle helmet is appropriate at these speeds.
- Do not exceed the 300 lb (136 kg) load capacity, which includes the rider and any cargo.
- Check local law before riding on public roads. A 250 W motor with 20 mph assist limit typically falls within Class 2 e-bike regulations in most US jurisdictions, but verify locally.
- Bed in the brake pads with progressive stops during the first few rides before relying on them in traffic.
- Do not ride through water deep enough to reach the hub motor or battery compartment.
- Charge only with the supplied charger, indoors, at room temperature, and on a non-flammable surface.
- Do not attempt to open, puncture, or modify the battery pack. Damaged lithium packs can vent and ignite.
- Use the programmable horn to alert pedestrians and other road users rather than shouting.
HKM-0893139 · 250 W rear-hub motor (100+ Nm torque) · 52 V 60 Ah lithium (3,120 Wh) · 20 mph assist · 37+ mi range · 20 x 4.0 in fat tires · 300 lb (136 kg) load capacity · step-through steel frame · hydraulic disc brakes · Bluetooth connected. Specifications are provided for reference; actual performance varies with rider weight, terrain, tire pressure, temperature, and riding style. This page describes the product only and is not legal advice regarding vehicle classification - confirm local regulations before riding on public roads.
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