Long-Range Fat-Tire Electric Commuter
HKM-989523 Electric Fat Tire Bike
The HKM-989523 takes the opposite approach to most fat-tire e-bikes: instead of a large motor and a small pack, it pairs a quiet 250 W geared rear hub with an unusually large 48 V 16.7 Ah battery holding 798 Wh. The result is up to 37 mi (60 km) of range from a bike that stays easy to live with - 15.5 mph assisted, 66 lb, a forgiving hi-tensile steel frame, 20 x 4.0 in fat tires that flatten broken pavement, and a 7-speed drivetrain that keeps pedalling useful. A USB port on the display keeps a phone alive on long days.
250 W Geared Hub, 45 Nm48 V 16.7 Ah / 798 Wh Pack15.5 mph AssistedUp to 37 mi Range20 x 4.0 in Fat Tires7-Speed Drivetrain160 mm Disc Brakes265 lb Payload Capacity
Motor
250 W
45 Nm geared rear hub
Battery
48 V 16.7 Ah
798 Wh removable 21700 cells
Top Speed
15.5 mph
25 km/h, electronically governed
Range
19-37 mi
31-60 km per charge
Tires
20 x 4.0 in
Fat tread, 5-30 psi range
Payload
265 lb
120 kg rider plus cargo
Overview
The HKM-989523 is built around a hi-tensile steel frame rather than aluminum, and that is a deliberate choice. Steel flexes fractionally under load and damps high-frequency road buzz in a way welded aluminum does not, which matters on a bike with no suspension. Paired with 20 x 4.0 in fat tires run at low pressure, the frame does most of the comfort work without adding the weight, cost, and maintenance of a fork. Complete weight lands at about 66 lb (30 kg).
Drive comes from a 250 W brushless geared rear hub producing 45 Nm of torque. Internal reduction gearing is what makes a modest nominal rating usable: it multiplies torque at low wheel speed, so the bike pulls a 15 percent gradient without labouring, and the freewheel inside the hub means there is almost no drag when you pedal with the power off. Assist is governed to 15.5 mph (25 km/h); region-specific configurations may permit a higher limit where the law allows it.
The pack is the standout number. 48 V 16.7 Ah works out to 798 Wh, roughly 50 percent more energy than a typical commuter e-bike carries, and it is fed to a motor that draws modestly. Real-world range spans 19-37 mi (31-60 km) depending on how much you pedal, and the pack is lockable and removable so it can be charged at a desk or swapped for a spare. A full charge from empty takes 5-7 hours on the supplied 2 A smart charger.
Everything else is chosen for low upkeep. Mechanical disc brakes with 160 mm rotors are simple to adjust and cheap to re-pad anywhere in the world, and their levers carry motor cut-off switches. The 7-speed derailleur and thumb shifter cover the cadence range from a standing start to the governed top speed. The step-over frame suits riders from roughly 5 ft 3 in to 6 ft 4 in, and frame colour and logo can be specified, which makes the bike practical for fleet operators as well as individual owners.
Key Features
250 W Geared Rear Hub Motor, 45 Nm
Internal planetary gearing lets a 250 W nominal motor deliver 45 Nm at the wheel, which is enough to hold speed up a 15 percent gradient with a rider aboard. The freewheel disengages the gearset when you are pedalling unpowered, so the bike still rolls like a bicycle when the pack is flat. It is a quiet motor - conversation at cruising speed is easy.
48 V 16.7 Ah Lithium Pack (798 Wh)
Assembled from automotive-grade 21700 cells, the pack holds 798 Wh - a large reservoir for a 250 W drive, which is why the range figure reaches 37 mi. It locks to the frame and lifts out with a key for indoor charging or for swapping in a second pack. The management system guards against overcharge, over-discharge, and temperature extremes; 5-7 hours on the 2 A charger takes it from empty to full.
Comfort Without a Fork: Steel Compliance + Low-Pressure Tires
There is no suspension fork, and the bike does not need one for the surfaces it is built for. The hi-tensile steel frame absorbs high-frequency vibration, and the 4.0 in tires can be run anywhere from 30 psi for efficient pavement riding down to 5-10 psi for cobbles, hardpack, or sand. Dropping pressure gives you a large contact patch and a plush ride with nothing to service.
Mechanical Disc Brakes with Motor Cut-Off
Front and rear mechanical discs on 160 mm rotors deliver consistent stopping in wet or dry conditions and dissipate heat well on long descents. Cable actuation is the practical choice here: pads swap in minutes, cable adjustment needs only a barrel turn, and no specialist tools or fluid are involved. Both levers cut motor power the instant they move.
7-Speed Derailleur with Thumb Shifter
A 7-speed rear derailleur and thumb shifter give crisp gear changes across the useful range. The ratios are matched to the assist so you are never over-geared pulling away from a stoplight and never spinning out at the 15.5 mph governed speed - you can hold a comfortable cadence in either situation.
20 x 4.0 in All-Terrain Fat Tires
20 in wheels wrapped in 4.0 in casings create a very large contact patch. That means flotation on sand and snow, grip on loose gravel, and reassuring stability on wet cobbles. The wide casing also resists pinch flats, which is exactly the failure mode that ruins commutes on a narrow-tyre bike.
Backlit LCD Console with Live Ride Data
The centrally mounted LCD shows speed, trip distance, odometer, battery percentage, and assist level. It is legible in direct sunlight and dims automatically as the light drops, so it never becomes a glare source on an evening ride home.
USB Charge Port and Custom Colour Options
A USB port on the display draws from the main pack to keep a phone or GPS unit charged on long rides - useful when navigation is doing the work. Frame colour and logo can be specified from a curated palette or supplied, which makes the platform workable for rental fleets, resorts, and delivery operators as well as private owners.
Full Specifications
Model
HKM-989523 | Electric Fat Tire Bike
Frame Material
Hi-tensile steel, step-over geometry, rigid fork
Motor
250 W brushless geared rear hub, 45 Nm torque
System Voltage
48 V DC
Battery
48 V 16.7 Ah lithium-ion (798 Wh), 21700 cells, removable and lockable
Charger
2 A smart charger, 100-240 V input
Charging Time
5-7 hours from empty
Battery Protection
Smart BMS: overcharge, over-discharge, and temperature protection
Top Speed
15.5 mph (25 km/h), electronically governed
Range Per Charge
19-37 mi (31-60 km), varies with terrain, rider weight, and assist level
Climbing Grade
Up to approximately 15 percent gradient
Walk Assist
2.5 mph (4 km/h) push mode for ramps and stairs
Drivetrain
7-speed rear derailleur with thumb shifter
Brakes
Mechanical disc, 160 mm rotors front and rear, with motor cut-off levers
Suspension
Rigid fork; compliance from the steel frame and low-pressure fat tires
Tires
20 x 4.0 in fat tires, 5-30 psi usable pressure range
Wheels
20 in rims, stainless spokes
Saddle
Padded commuter saddle, upright riding position
Display
Backlit LCD with USB output: speed, battery percentage, PAS level, trip, odometer
Assist Modes
5 levels of pedal assist plus zero assist and walk mode
Weather Rating
IP54 electrical components; rain and splash resistant
Payload Capacity
265 lb (120 kg) rider plus cargo
Bike Weight
Approximately 66 lb (30 kg) including battery
Recommended Rider Height
5 ft 3 in to 6 ft 4 in (160-193 cm)
Certifications
CE, RoHS; battery cells UN38.3 tested
Battery, Range, and Charging
The 48 V 16.7 Ah pack stores 798 Wh. Put that next to the 400-500 Wh that a typical city e-bike carries and the difference in daily usefulness is obvious - especially behind a 250 W motor, which draws far less than a high-power hub. Energy in the pack combined with modest consumption is the whole reason a bike in this class can quote 37 mi rather than 20.
The honest range band is 19-37 mi (31-60 km). The top of that band assumes flat ground, assist level 2, and a 165 lb (75 kg) rider contributing real pedal effort. The bottom assumes hills, heavy throttle use, a headwind, or a loaded rear rack. Cold below 40 F (4 C) temporarily costs 10-20 percent of usable capacity and it returns when the pack warms up. The display shows a live battery percentage rather than a coarse bar graph, so you can watch how your riding style maps to consumption.
Tip: If the bike will sit unused for more than a month, store the pack at 30-70 percent charge and top it up every 4-6 weeks. Avoid leaving it on the charger at 100 percent for days at a time; cells held at full charge age faster than cells left part-full.
The pack unlocks with the supplied key and lifts out in seconds, so it can travel to an office desk while the bike stays locked at the rack. Fleet operators often run a second pack per bike and swap at the depot instead of waiting on a charge cycle.
Daily Use & Care
- Match tire pressure to the surface: 25-30 psi for efficient pavement riding, 10-15 psi for gravel and hardpack, 5-8 psi for sand or snow.
- Rinse and dry the bike after wet or salted rides. Steel frames are protected by their paint, so touch up any deep chips promptly to keep corrosion from starting.
- Check mechanical disc brake cable tension monthly. A quarter turn on the barrel adjuster restores lever feel as the pads wear.
- Clean and re-lubricate the chain every 100-150 mi or after any wet or dusty ride, and check derailleur indexing at the same time.
- Re-torque the axle nuts, stem, and seatpost clamp weekly for the first month, then monthly.
- Charge indoors at room temperature and unplug when the charger indicator turns green.
- Keep the USB port and charge port covers closed when the bike is parked outside; the electronics are IP54 rated for splashes, not for immersion.
What's in the Box
- 1 x HKM-989523 electric fat tire bike, approximately 85 percent pre-assembled
- 1 x 48 V 16.7 Ah removable lithium battery pack
- 1 x 2 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 pedals
- 1 x Kickstand (pre-installed)
- 1 x Illustrated user manual and assembly guide
Frequently Asked Questions
How long does the battery really last on a single charge?+
Range depends on rider weight, terrain, assist level, and weather. In favourable conditions - flat ground, assist level 2, a 165 lb rider pedalling - expect up to 37 mi (60 km). Heavy throttle use or steep hills brings that down toward 19 mi (31 km). The live battery percentage on the display makes it easy to learn your own numbers over the first few rides.
Does it come assembled?+
The bike arrives approximately 85 percent pre-assembled. You attach the front wheel, handlebar, pedals, and saddle, then check brake and derailleur alignment. Tools and an illustrated manual are included, and most owners finish in 20-30 minutes.
Why a 250 W motor instead of something bigger?+
Because of what it is paired with. A 250 W geared hub producing 45 Nm is efficient, quiet, light, and legal as a pedal-assist bicycle in far more places than a high-power motor. Feeding it from a 798 Wh pack converts that efficiency directly into range. If you want a 40 mph machine this is not it; if you want to ride 30 mi without thinking about charge, it is well matched.
What is the recommended rider height and weight?+
The step-over frame fits riders of roughly 5 ft 3 in to 6 ft 4 in (160-193 cm). Maximum payload is 265 lb (120 kg) including rider and cargo. The wide tires and steel frame keep handling stable across that whole range.
Can I ride it in the rain or through puddles?+
Yes. The electrical components are IP54 rated, so light rain and splashes are fine. Avoid submerging the battery or motor, do not pressure-wash the bike, and dry it after wet rides to keep connectors and the steel frame in good condition.
How does the walk-assist mode work?+
Hold the down button and the motor drives the bike forward at about 2.5 mph (4 km/h) while you walk alongside. It is intended for pushing 66 lb of bike up a ramp, a stairwell channel, or a steep driveway rather than for riding.
Can I run a second battery?+
Yes. The pack is a standard removable unit, so a spare can be carried and swapped in seconds without tools. Fleet operators commonly run two packs per bike so a vehicle is never waiting on a charger.
Can I choose the frame colour or add my own logo?+
Yes. Colour can be selected from a curated palette, and logo artwork can be applied for fleet, rental, or business use. Contact us with quantities and artwork before ordering so the request can be confirmed against current production.
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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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 Battery798 Wh PackIP54 Rated7-Speed DrivetrainUSB Charge Port
Why Choose the HKM-989523
Range Comes from Energy, Not Watts
It is easy to sell a big motor and quietly fit a small pack. This bike does the reverse: a modest, efficient 250 W drive behind a 798 Wh battery. The practical consequence is that a 20 mi round trip is roughly half a charge, so most owners plug in twice a week.
Genuinely All-Surface
A 4.0 in tire run at 8 psi floats over sand and packed snow, and the same tire at 28 psi rolls efficiently on tarmac. Adjusting pressure changes the bike from a beach cruiser to a city commuter in about two minutes with a floor pump.
Simple Systems Are Easy to Live With
Mechanical disc brakes, a cable derailleur, and a geared hub motor can be serviced by any bicycle shop, anywhere. There is no proprietary fluid, no mid-drive gearbox, and no suspension service interval to plan around.
Quiet Enough for Shared Paths
Planetary gearing inside the hub is well damped and the motor draw is low, so the drive is barely audible above tire noise. On a shared cycle path, pedestrians hear you approach rather than being startled by a motor.
Steel Frame, Long Service Life
Hi-tensile steel takes impacts and load cycles that fatigue lighter materials, and it can be repaired rather than replaced. For a bike that gets locked up outdoors, dropped on its side, and loaded with shopping, that durability is worth the extra pounds.
Built for Daily Commuting
IP54 electronics, a lockable pack, sealed connectors, and a USB port for a phone add up to a bike that handles a weekday commute in variable weather rather than a fair-weather weekend toy.
Controls & Indicators
Power Button
On the battery pack; hold to switch the system on and off
Mode Buttons
Up and down buttons on the console cycle through 5 pedal-assist levels plus zero assist
Walk Assist
Hold the down button for 2.5 mph push mode when walking the bike
Speedometer
Live speed on the backlit LCD, switchable between mph and km/h
Battery Gauge
Live percentage readout plus a segmented charge bar
Backlight
Long-press the up button to toggle the display backlight for night riding
Shifter
Right-hand thumb shifter for the 7-speed rear derailleur
Pre-Ride Safety Checklist
- Check tire pressure and set it for the surface: 25-30 psi for pavement, 10-15 psi for gravel, 5-8 psi for sand or snow.
- Squeeze both brake levers. The pads should contact the rotors with about a third of the lever travel remaining; take up slack at the barrel adjuster if not.
- Confirm the battery is locked into the frame and the display shows the state of charge you expect.
- Spin both wheels and check that the rims run true and nothing rubs the pads or the frame.
- Verify the axle nuts, stem bolts, and seatpost clamp are tight, and rock the bike with the front brake applied to check for headset play.
- Shift through all 7 gears at low speed in a clear area and confirm the chain moves cleanly without skipping.
- Test the assist at level 1 before setting off in traffic so the first surge of power is not a surprise.
- Wear a helmet, and switch on a light if you will be riding near dusk.
Quick Troubleshooting
The motor does not assist when I pedal.+
Check that the display is on and showing charge, that the assist level is above zero, and that neither brake lever is being held - the cut-off switches disable the motor while a lever is pulled. Confirm the battery is fully seated and locked. If an error code appears, note it and contact support.
Range has dropped compared with when the bike was new.+
Tire pressure is the usual cause; a fat tire at 8 psi on pavement costs a great deal of range. Cold weather also temporarily reduces capacity. If the drop is more than 30 percent, persists in warm weather, and the bike has many charge cycles on it, the pack is nearing the end of its service life.
The brakes feel weak or the lever pulls to the grip.+
Mechanical discs need occasional cable adjustment. Turn the barrel adjuster out a quarter turn at a time until the pads engage with roughly a third of the lever travel remaining. If that does not help, the pads are worn out and should be replaced.
The chain skips under load or will not sit in a gear.+
The derailleur indexing has drifted. Adjust the barrel adjuster at the shifter a quarter turn at a time while pedalling until the chain sits cleanly in each cog. If it skips only in the smallest cogs, the cassette and chain are worn and should be replaced together.
The ride feels harsh on rough pavement.+
This bike has no suspension fork by design, so tire pressure is the adjustment. Drop to 12-15 psi and the difference is substantial. Check the saddle height and angle at the same time; too high a saddle transfers far more road shock to the rider.
The display shows an error code and the motor will not run.+
Switch the system off, wait 30 seconds, and switch it back on. If the code returns, record the exact code and the conditions that produced it and contact support - codes point to specific faults in the controller, motor, or battery circuits.
Certifications & Standards
The HKM-989523 is produced in a facility operating under an ISO 9001 quality management system. The 21700 cells and the assembled 48 V 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
Assist is governed to 15.5 mph (25 km/h), which places the HKM-989523 within the pedal-assist bicycle category in many jurisdictions - but classification also depends on motor rating and local rules, so confirm before riding on public paths. Read the manual before the first ride and take a few minutes in an open area to get used to how the assist engages.
- Wear a helmet on every ride, and use lights whenever visibility is reduced.
- Do not exceed the 265 lb (120 kg) payload capacity, which includes rider and cargo.
- Confirm local rules on motor rating, assist speed, and where pedal-assist bicycles may be ridden before using public roads or paths.
- Bed in new brake pads with 10-15 progressive stops from moderate speed before relying on full braking performance.
- The electronics are IP54 rated for rain and splashes. Do not submerge the battery or motor, and do not pressure-wash the bike.
- Charge only with the supplied charger, indoors, at room temperature, on a non-flammable surface, and do not leave a charging pack unattended overnight.
- Do not open, puncture, or modify the battery pack. Damaged lithium cells can vent and ignite.
- Reduce speed on wet, sandy, or icy surfaces. Fat tires improve grip but braking distances still lengthen considerably.
HKM-989523 · 250 W brushless geared rear hub, 45 Nm · 48 V 16.7 Ah lithium (798 Wh, 21700 cells) · 15.5 mph (25 km/h) governed assist · 19-37 mi (31-60 km) range · 20 x 4.0 in fat tires · 265 lb (120 kg) payload · hi-tensile steel frame · 160 mm mechanical disc brakes · 7-speed derailleur · backlit LCD with USB output · IP54 electrical components. Specifications are provided for reference; actual performance varies with rider weight, terrain, tire pressure, temperature, and riding style. Range figures are measured under moderate pedal assist on level ground. 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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