Fat-Tire Electric Mountain Bike
HKM-398547 Electric Fat Tire Mountain Bike
The HKM-398547 puts a 1000 W brushless hub motor into a 6061 aluminum fat-tire frame for riders who want one bike for pavement, trail, sand, and snow. The 48 V 16 Ah pack stores 768 Wh and the 20 x 4.0 in tires float over soft surfaces, while a 7-speed drivetrain and mechanical disc brakes keep the spec honest and easy to service. An LCD shows speed, battery, and trip data at a glance, and the bike is rated for about 300 lb of rider and cargo.
1000 W Brushless Hub Motor48 V 16 Ah / 768 Wh31 mph Top Speed20 x 4.0 in Fat Tires7-Speed DrivetrainMechanical Disc Brakes6061 Aluminum Frame~300 lb Load Capacity
Motor
1000 W
brushless rear hub motor
Battery
48 V 16 Ah
768 Wh removable lithium
Top Speed
31 mph
50 km/h, throttle only
Range
19-37 mi
31-60 km, varies with assist
Tires
20 x 4.0 in
Fat tread, all-terrain
Load Capacity
300 lb
136 kg rider plus cargo
Overview
The HKM-398547 is built around a 6061 aluminum frame sized for fat-tire clearance and an upright riding posture. The geometry is stable at speed yet agile through tight trail switchbacks, and the frame withstands repeated stress cycles without fatigue in varied climates.
Power comes from a 1000 W brushless hub motor fed by a 48 V 16 Ah pack that stores 768 Wh. The twist throttle gives immediate acceleration; a 7-speed derailleur lets you add pedal power to extend range or help on climbs. The hub motor delivers torque straight to the wheel with no chain or belt in the drive path, which keeps maintenance low.
Real-world range is wide because the bike adapts to how you ride. Throttle-only at higher speed lands closer to 19-22 mi. Moderate pedal-assist on the same terrain regularly returns 31-37 mi. Cold weather below 40 F (4 C) temporarily reduces available capacity by 10-15 percent; it returns once the pack warms up.
Comfort hardware matches the frame. The 20 x 4.0 in fat tires act as a layer of pneumatic suspension over small bumps, mechanical disc brakes give consistent stopping in the wet, and the LCD keeps speed and battery in view. Internal cable routing keeps the lines clean and protected from trail debris.
Key Features
1000 W Brushless Hub Motor
A 1000 W brushless motor is laced directly into the rear wheel hub. There is no chain or belt between the motor and the ground, so drive losses stay low and maintenance is limited to keeping the axle nuts torqued. The motor engages within milliseconds of throttle input and holds speed up moderate grades without overheating.
48 V 16 Ah Lithium Pac (768 Wh)
The pack sits in the frame and lifts out with a key for indoor charging. 768 Wh is enough for a full week of short commutes between charges. A full recharge from empty takes about 5-7 hours on the supplied charger; partial top-ups take proportionally less.
Fat-Tire Pneumatic Suspension
The 20 x 4.0 in high-volume tires absorb trail chatter and small bumps without a heavy suspension fork, lowering weight and complexity. Run them at 8-12 psi for sand, snow, and loose gravel, or 20-25 psi for efficient pavement rolling.
Mechanical Disc Brakes, Front and Rear
Mechanical disc brakes with large rotors provide consistent, fade- resistant stopping power in rain, mud, and dust - performance that rim brakes cannot match in poor conditions. Cables are simple to adjust and service at home.
7-Speed Drivetrain
A 7-speed derailleur with index shifter gives usable pedaling cadence from walking pace up to cruising speed. The wide gear range is what lets riders climb grades without overheating the battery and what extends range on long rides.
20 x 4.0 in All-Terrain Fat Tires
The 4.0 in width creates a contact patch roughly 40 percent larger than a standard mountain bike tire, improving grip on loose or uneven terrain. The aggressive tread bites in and sheds mud efficiently.
LED Headlight and Integrated Brake Light
A bright LED headlight runs off the main pack so there are no separate batteries to keep charged. A brake light that illuminates whenever either brake lever is pulled adds visibility from behind - useful in traffic and at dusk.
Accessory-Ready Rear Rack Mounts
Mounting points for racks, fenders, and additional lighting let you tailor the bike to commuting or touring. A rear rack (sold separately or fitted at order) carries cargo within the rated load.
Full Specifications
Model
HKM-398547 | Electric Fat Tire Mountain Bike
Frame Material
6061 aluminum alloy, fat-tire geometry
Motor
1000 W brushless rear hub motor
System Voltage
48 V DC
Battery
48 V 16 Ah lithium-ion (768 Wh), removable and lockable
Charger
48 V smart charger, 100-240 V input
Charging Time
5-7 hours from empty
Battery Cycle Life
Approximately 800 charge cycles to 80 percent capacity (typical)
Top Speed
31 mph (50 km/h)
Range Per Charge
19-37 mi (31-60 km), varies with terrain, rider weight, and assist level
Climbing Grade
Up to approximately 15 degrees sustained; peak torque tuned for up to ~20 degrees
Peak Torque
Optimized for inclines up to approximately 20 degrees
Drivetrain
7-speed derailleur with index shifter
Brakes
Mechanical disc brakes, front and rear, with power-off levers
Suspension
Fat-tire pneumatic suspension (no fork); rigid rear
Tires
20 x 4.0 in fat tires, knobby all-terrain tread
Wheels
20 in alloy rims, stainless spokes
Saddle
Ergonomic trail saddle with grippy cover
Display
Backlit LCD: speed, battery level, trip distance, odometer, assist mode
Throttle
Twist-grip throttle with pedal-assist (PAS) and manual modes
Lighting
LED headlight, integrated brake-activated tail-light, powered by main battery
Load Capacity
300 lb (136 kg) rider plus cargo
Bike Weight
65-72 lb (29-33 kg) including battery
Recommended Rider Height
5 ft 3 in to 6 ft 3 in (160-191 cm)
Certifications
CE, RoHS; battery cells UN38.3 tested
Battery, Range, and Charging
The 48 V 16 Ah pack stores 768 Wh of energy. For context, many commuter e-bikes ship with 400-600 Wh, so this pack sits at the upper end of the usual range for its class. A smart BMS monitors cell balance, temperature, and discharge to protect the pack over hundreds of cycles.
Real-world range depends on how much you pedal, rider and cargo weight, tire pressure, and terrain. Throttle-only at higher speed lands closer to 19-22 mi. Moderate pedal-assist on the same terrain regularly returns 31-37 mi. Cold weather below 40 F (4 C) temporarily reduces available capacity by 10-15 percent; it returns once the pack warms up.
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 compared with charging in an unheated garage.
The pack unlocks with the supplied key and lifts out of the frame in a few seconds for indoor charging. Two keys are included. Charging with the pack installed works equally well through the frame-side charge port.
Daily Use & Care
- Tire pressure sets the character of the bike. Run 8-12 psi for sand, snow, and loose gravel; 20-25 psi for pavement efficiency.
- Rinse the frame, rims, and drivetrain with fresh water after riding on salted roads, wet gravel, or muddy trails.
- Check that both axle nuts and the stem bolts are torqued before the first ride of each week. Hub-motor torque works fasteners loose faster than on a conventional bicycle.
- Wipe and re-lubricate the chain every 100-150 mi, or after any ride through standing water or dusty conditions.
- Inspect brake pad and rotor condition monthly; mechanical disc pads wear visibly and are simple to replace.
- Charge indoors at room temperature. Unplug the charger once the indicator turns green rather than leaving it connected for days.
- Keep the display and charge port covers closed when parked outside so moisture stays out of the connectors.
What's in the Box
- 1 x HKM-398547 electric fat tire mountain bike, approximately 85 percent pre-assembled
- 1 x 48 V 16 Ah removable lithium battery pack
- 1 x 48 V 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 Front and rear lighting set (pre-installed)
- 1 x User manual and assembly guide
Frequently Asked Questions
How much assembly is required out of the box?+
The bike ships approximately 85 percent assembled. Remaining steps are fitting the front wheel, straightening and bolting the handlebar, installing the pedals and saddle, and checking brake alignment. Budget 30-45 minutes with the supplied tools. Have a bike shop check torque and brake bedding if you are not comfortable doing it yourself.
Is this bike suitable for sand or snow?+
Yes. At 8-12 psi the 4.0 in wide fat tires float over sand, snow, and loose gravel where a narrower tire would sink. Inflate to 20-25 psi for hard-packed surfaces and pavement to reduce rolling resistance.
What is the actual range I should plan for?+
Plan for 19-37 mi depending on how much you pedal. Throttle-only riding at higher speeds lands closer to 19-22 mi. Moderate pedal-assist on mixed terrain regularly returns 31-37 mi. Heavier riders, headwinds, hills, and low tire pressure all reduce range.
Is a license or registration required?+
Rules vary by jurisdiction. The HKM-398547 has a 1000 W motor and reaches 31 mph (50 km/h), which exceeds the common three-class e-bike limits in many US states. We recommend checking your local and state regulations before riding on public roads or paths.
How long does the battery take to charge?+
About 5-7 hours from fully empty with the supplied 48 V charger. Partial top-ups take proportionally less time; there is no need to run the pack down before recharging, and the BMS stops charging when full.
Can I pedal it if the battery runs out?+
Yes. The 7-speed drivetrain works independently of the motor. The bike is heavy at 65-72 lb, so pedaling home unassisted is slow going, but it is entirely possible on flat ground.
Are the brakes strong enough for the speed?+
Mechanical disc brakes with large rotors are the appropriate specification for a 31 mph fat bike. Bed the pads in during the first few rides with 10-15 progressive stops, and keep the rotors clean for consistent performance in the wet.
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, and lock it to the frame for security when parked.
Service & Policies
Free Shipping on All Orders
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.
180 Days Purchase Protection
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.
30 Days Money-Back Guarantee
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 Battery768 Wh PackMechanical Disc Brakes6061 AluminumFat Tires
Why Choose the HKM-398547
One Bike, Many Surfaces
Pavement, trail, sand, and snow all become rideable on the same machine. The fat tires and upright geometry make the HKM-398547 a practical daily bike rather than a single-purpose toy.
Fat-Tire Grip Without Heavy Suspension
The 4.0 in tires absorb chatter and small bumps on their own, so you get comfort and grip without the weight and upkeep of a suspension fork. The bike stays agile through tight trail sections.
Two Ways to Ride
Twist the throttle for immediate acceleration, or shift through the 7-speed cassette and pedal. Most owners mix both - throttle to get moving, pedals to extend range, and motor for hills.
Direct-Drive Simplicity
The motor lives in the rear hub with no mid-drive gearbox, belt, or extra chain to service. Fewer moving parts in the drive path means less to maintain and a notably quiet ride.
Honest, Serviceable Spec
Mechanical disc brakes and a standard 7-speed drivetrain are easy to adjust and repair at home, and the 6061 aluminum frame is built to last through varied climates and repeated stress cycles.
Built for Daily and Trail Use
Sealed electrical connectors, a lockable battery compartment, and internal cable routing that shields lines from debris make sense for a bike ridden on trails and parked outside.
Controls & Indicators
Power Button
Located on the battery pack; hold to switch the system on and off
Mode Buttons
Display buttons cycle through pedal-assist levels and readouts
Twist Throttle
Right-hand grip; proportional response, works independently of pedal-assist level
Speedometer
Live speed readout in mph, switchable to km/h in the settings menu
Battery Gauge
Charge indicator plus percentage readout on the LCD
Light Switch
Toggle the LED headlight and integrated brake light from the display
Shifter
Right-hand index shifter for the 7-speed rear derailleur
Pre-Ride Safety Checklist
- Check tire pressure and set it for the terrain: 8-12 psi for sand, snow, or loose gravel; 20-25 psi for pavement.
- Squeeze both brake levers. They should firm up well before reaching the grip, with no excessive slack.
- Confirm the battery is seated and locked, and that the display shows the expected state of charge.
- Spin both wheels and check that the rims run true and nothing rubs the brake pads or the frame.
- Verify the 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 or on technical trail.
- Switch on the headlight and tail light if you will be riding near dusk, and wear a helmet rated for the speeds this bike reaches.
- If carrying cargo, confirm total weight is under 300 lb and the load is secured before riding.
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 the display shows an error code, note it and contact support.
Range dropped noticeably compared with when it was new.+
First check tire pressure; a soft tire on pavement is the most common cause. Then consider temperature - cold reduces available capacity temporarily. If range is down more than 30 percent year-round after many charge cycles, the pack may be approaching the end of its service life.
The brakes feel weak or rub.+
Mechanical disc brakes need periodic pad and cable adjustment. Check that the pads are not worn below 1 mm, the rotors are true, and the cable barrel adjuster is set so the lever firms up before the grip. Replace pads or realign the caliper if rubbing persists.
The chain skips under hard pedaling.+
The derailleur indexing is likely out of adjustment, or the chain and cassette are worn. Adjust the barrel adjuster a quarter turn at a time to align the indexing. If the chain skips only in the smallest cogs, the cassette is worn and should be replaced along with the chain.
The front wheel feels unstable over bumps.+
Check that the front wheel is seated in the dropouts and the axle is tight. Because this model uses fat-tire suspension rather than a fork, very rough terrain is better taken at moderate speed; lower tire pressure adds compliance.
The display shows an error code and the bike will not move.+
Power the system off, wait 30 seconds, and switch it back on. If the code returns, note the exact code and the conditions that produced it, then contact support - error codes map to specific faults in the controller, motor, or throttle circuits.
Certifications & Standards
The HKM-398547 is produced in a facility operating under an ISO 9001 quality management system. The battery cells and the assembled pack carry the 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 a high-output electric bicycle capable of 31 mph. Read the manual fully before the first ride and practice throttle control in an open, traffic-free area until the response feels predictable.
- Wear a helmet on every ride. At 31 mph a bicycle helmet is the minimum; many riders choose a certified motorcycle or downhill helmet at these speeds.
- Do not exceed the 300 lb (136 kg) load capacity, which includes the rider and cargo.
- Check local law before riding on public roads or paths. A 1000 W motor with 31 mph top speed may place this vehicle outside standard e-bike classifications in your area.
- Bed in the brake pads with 10-15 progressive stops during the first few rides before riding at full speed.
- Do not ride through water deep enough to reach the hub motor or the battery compartment.
- Charge only with the supplied charger, indoors, at room temperature, and on a non-flammable surface. Do not leave a charging battery unattended overnight.
- Do not attempt to open, puncture, or modify the battery pack. Damaged lithium packs can vent and ignite.
- Reduce speed substantially on sand, wet surfaces, and downhill grades; fat tires add grip but do not eliminate the risk of losing traction.
HKM-398547 · 1000 W brushless rear hub motor · 48 V 16 Ah lithium (768 Wh) · 31 mph top speed · 19-37 mi range · 20 x 4.0 in fat tires · 300 lb (136 kg) load capacity · 6061 aluminum frame · mechanical disc brakes · 7-speed. 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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We understand that maintenance needs may arise. When you purchase from us, you gain access to our unparalleled service ecosystem designed for maximum convenience and reliability.
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For minor repairs or part replacements that can be handled personally, we provide cost-price genuine parts during the warranty period. Each order is accompanied by clear, step-by-step video tutorials to guide you through the self-repair process seamlessly.
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If you purchase products from our website, you have 24 months to request repairs or replacement if any products turns out to be faulty or are not as advertised. During the warranty period if any product is found to have a manufacturer defect, we will repair or replace the defective part(s). If a product cannot be repaired or replaced within a reasonable time, you can request a refund or price reduction. We are confident that our products are of great quality and even better value. However, if upon receiving and inspecting your item you decide that you want to return it, you will have 30 days as of the date of shipment arrival to return it for a refund minus the shipping cost.
