Electric Bicycles >>
HKM-9031891 52V 25Ah Electric Fat Tire Bike, 1500W Brushless Motor, 31 mph Top Speed, 20 x 4.0 in Fat Tire, Hydraulic Disc Brakes
HKM-9031891 Electric Fat Tire Bike
The HKM-9031891 pairs a 1500 W brushless rear hub motor with a 52 V 25 Ah lithium pack (1300 Wh) in a 6061 aluminum alloy frame. 20-inch fat tires, full suspension, and hydraulic disc brakes make it a practical choice for mixed-surface commuting, beach paths, and weekend trail loops.
Overview
The HKM-9031891 is a compact 20-inch fat-tire electric bike built around a 6061 aluminum alloy frame and a 1500 W brushless rear hub motor. The 20 x 4.0 in tires spread weight over a large contact patch, giving the bike predictable grip on pavement, gravel, hard-packed sand, and light snow. The upright riding position, wide saddle, and motorcycle-style handlebar place the rider in a comfortable posture for commuting, errands, and weekend exploring.
Power comes from a 52 V 25 Ah lithium pack storing roughly 1300 Wh of energy. A twist throttle provides immediate acceleration, while a 7-speed derailleur and 5 pedal-assist levels let you add human power to stretch range. The controller keeps acceleration smooth and prevents sudden torque spikes that can break traction on loose surfaces.
Real-world range varies with terrain, rider weight, tire pressure, and how much you pedal. Throttle-only cruising on flat pavement typically returns 30-40 mi. Moderate pedal-assist on the same terrain stretches that to 50-70 mi. Aggressive pedaling at low assist can push the upper end of the range. Cold weather, soft tires, and steep hills reduce those numbers; warmer months and firmer tires push them back up.
A lockable hydraulic front fork and a rear coil shock absorb bumps and potholes. The combination of fat tires and suspension keeps the wheels in contact with rough surfaces and reduces rider fatigue on longer rides. Hydraulic disc brakes at both wheels provide consistent stopping power with light lever effort. Power-off brake levers cut motor drive the moment either lever is pulled.
Key Features
A 1500 W brushless motor is laced 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 produces enough torque for sandy paths and moderate hills.
The pack stores 1300 Wh of energy and lifts out of the frame with a key for indoor charging. A full recharge from empty takes about 3-5 hours with the supplied charger; partial top-ups take proportionally less.
A hydraulic front fork with mechanical lockout smooths broken pavement and gravel when unlocked, and firms up for efficient pedaling on smooth roads when locked. A rear coil shock under the seat takes care of larger hits.
Sealed hydraulic lines actuate both calipers. Lever effort stays light and predictable when the rotors get hot, and there are no cables to stretch or corrode. Power-off brake levers cut motor drive the instant either lever is pulled.
A 7-speed derailleur with an index shifter gives usable pedaling cadence from walking pace up to cruising speed. The wide gear range lets riders climb moderate grades without overheating the motor or battery.
Run at low pressure the wide casing spreads rider and cargo weight over a large contact patch. The same tires add grip and comfort on gravel, wet pavement, light snow, and park paths where a narrower tire would skate around.
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.
A sturdy rear rack accepts panniers, a backpack, or a small cargo bag. The motorcycle-style handlebar and wide saddle create an upright, comfortable posture for commuting and longer recreational rides.
The Charge That Lasts
The 25Ah cell pack gives the HKM-9031891 the reserve to finish the day without a mid-route charge.
Composed where it matters, light everywhere else — that is the whole idea. Considered in the hand, quiet in use, and calm at the end of the day.
Full Specifications
Battery, Range, and Charging
The 52 V 25 Ah pack stores 1300 Wh of energy. That is roughly double the capacity of a typical commuter e-bike, giving the 31 mph top speed room to breathe without forcing constant charging.
Real-world range depends on four variables more than anything else: how much you pedal, rider and cargo weight, tire pressure, and terrain. Throttle-only riding on flat pavement at moderate speed lands in the 30-40 mi band. Moderate pedal-assist on the same terrain regularly returns 50-70 mi. Cold weather below 40 F (4 C) temporarily reduces available capacity by 10-20 percent; it returns once the pack warms up.
The pack unlocks with the supplied key and lifts out of the frame in a few seconds, so you can charge it at a desk while the bike stays locked outside. 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 15-20 psi on pavement for lower rolling resistance; drop to 10-12 psi for gravel and dirt so the tire can flatten and grip the surface.
- Rinse the frame, rims, and drivetrain with fresh water after riding on salted roads or wet gravel. Road film attacks aluminum fasteners over time if left in place.
- 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 thickness monthly. Hydraulic pads wear silently until they are gone; replace when the friction material is under 1 mm.
- 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 the bike is parked outside so moisture stays out of the connectors.
What's in the Box
- 1 x HKM-9031891 electric bike, approximately 85 percent pre-assembled
- 1 x 52 V 25 Ah removable lithium battery pack
- 1 x 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 User manual and assembly guide
Frequently Asked Questions
How much assembly is required out of the box?+
What is the actual range I should plan for?+
Is a license or registration required?+
How long does the battery take to charge?+
Can I pedal it if the battery runs out?+
Will the brakes handle the speed?+
Is the battery removable for indoor charging?+
What tire pressure should I use?+
Service & Policies
Why Choose the HKM-9031891
The upright handlebar, wide saddle, and mid-mounted battery create a comfortable riding posture that works for commuting, errands, and recreational loops. You sit high enough to see traffic, low enough to put a foot down easily.
Potholes, expansion joints, brick-paved lanes, and gravel shortcuts all become rideable surfaces when the front fork and rear shock absorb what a rigid frame would transmit directly to the rider. The fork lockout lets you firm the ride up on smooth pavement.
Twist the throttle for immediate acceleration, or shift through the 7-speed cassette and pedal. Most owners mix both - throttle to get moving from a stop, pedals to extend range, and motor for hills.
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.
The 20 x 4.0 in tires roll over obstacles that would stop narrower tires and maintain traction on loose surfaces. That opens up beach paths, rail trails, and unpaved shortcuts that would otherwise be off limits.
Sealed electrical connectors, a covered and lockable battery compartment, and hydraulic brake lines that resist corrosion in road film all make sense for a bike that gets ridden to work and parked outside.
Controls & Indicators
Pre-Ride Safety Checklist
- Check tire pressure and set it for the terrain you plan to ride: 15-20 psi for pavement, 10-12 psi for gravel or dirt.
- Squeeze both brake levers. They should firm up well before reaching the grip, with no sponginess that would indicate air in the hydraulic line.
- 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 that 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 and tail-light if you will be riding near dusk, and wear a helmet rated for the speeds this bike reaches.
Quick Troubleshooting
The motor does not engage when I twist the throttle.+
Range dropped noticeably compared with when it was new.+
The brakes feel spongy at the lever.+
The chain skips under hard pedaling.+
The front fork rattles over bumps.+
The display shows an error code and the bike will not move.+
Certifications & Standards
The HKM-9031891 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 330 lb (149 kg) load capacity, which includes the rider and cargo.
- Check local law before riding on public roads or paths. A 1500 W motor and 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 gravel, wet surfaces, and downhill grades; fat tires add grip but do not eliminate the risk of losing traction.
Every product we offer includes a 180-day purchase protection plan at no additional cost. This coverage extends beyond a standard warranty, reflecting our confidence in product quality and our ongoing commitment to your satisfaction.
The protection plan is designed to provide practical help in real-world situations. Whether you encounter a manufacturing issue, a performance problem, or an unexpected accident, our team is ready to assist with clear, fair solutions.
What Is Covered
Manufacturing Defects
We replace items with material or workmanship flaws at no charge.
Performance Failures
Free repair or replacement if the product fails under normal use.
Accidental Damage
One-time courtesy replacement at a reduced price.
Zero Hidden Fees
All shipping costs for replacements and returns are covered.
How to File a Claim
How This Differs from the Warranty
The 180-day purchase protection includes accidental damage and performance failures that are typically not covered by a standard warranty. It provides an additional layer of support during the first six months after purchase, giving you greater confidence and peace of mind.
We want you to be completely satisfied with your purchase. If for any reason you are not fully happy, you may return your item within 30 days of delivery for a full refund. No lengthy forms, no unnecessary questions.
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Return Eligibility
30-Day Window
Request a return within 30 days of delivery.
Original Condition
Unworn or unused, with tags and original packaging.
Proof of Purchase
A receipt or order number is required.
Fast Refund
Refund processed within 10 business days.
How to Start a Return
Returns & Exchanges Overview
Damages & Exchanges
Please inspect your order as soon as it arrives. If the item is defective, damaged, or incorrect, contact us immediately so we can evaluate the issue and make it right. For exchanges, the fastest option is to return the original item and place a new order for the replacement.
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The warranty is designed to be simple and accessible. You only need your proof of purchase to begin a claim, and our team will assess the issue promptly. If a manufacturing issue arises, we will make it right.
What the Warranty Covers
Comprehensive Coverage
Every part warranted for two full years.
Free Repair or Replacement
Whichever is faster, at no cost to you.
Quick Turnaround
Claims assessed within 1 business day.
Transferable
Warranty follows the product, not the owner.
How to File a Warranty Claim
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Contact Information
24/7 Phone
+1 (209) 280-3200
support@hekomart.com
Address
3401 Dale Rd, Modesto, CA 95356
Support Hours
Available 24 hours a day, 7 days a week
