Electric Bicycles >>
HKM-9720019 36V 350W Electric Mountain Bike, 10.4Ah Battery, 21-Speed Drivetrain, 20 mph Top Speed, Disc Brakes, 265 lb Load
HKM-9720019
350 W 20 mph Electric Mountain Bike
The HKM-9720019 uses a lightweight 6061 aluminum diamond frame - the classic mountain bike triangle that offers a strong strength-to-weight ratio for a bicycle frame design. At roughly 48 lb complete with battery, this is one of the lighter e-bikes in the lineup, which makes it easier to lift onto a car rack or carry up apartment stairs.
Key Features
8 details that make the HKM-9720019 a dependable ride.
350 W Geared Rear Hub Motor
A 350 W geared brushless hub motor uses internal planetary gearing to multiply torque at low speeds, which is where hill climbing happens. This design provides better climbing performance per watt than a direct-drive hub, and the internal freewheel means no drag when pedaling unassisted.
21-Speed Wide-Range Drivetrain
Three front chainrings paired with a 7-speed Shimano rear cassette give 21 distinct gear ratios. The wide range means you can pedal comfortably at 5 mph up a steep climb or spin at 20 mph on the flats without the motor doing all the work. This is the widest gear range in the HKM e-bike lineup.
Lightweight Aluminum Diamond Frame
The classic double-triangle diamond frame offers a strong stiffness-to-weight ratio for a bicycle frame configuration. Built from 6061 aluminum alloy, it keeps total bike weight to roughly 48 lb - noticeably lighter than fat tire or full-suspension alternatives.
Lockable Suspension Fork
An 80 mm travel suspension fork with a mechanical lockout lever on the crown. Unlock it for trails and broken pavement; lock it out for maximum pedaling efficiency on smooth roads. The lockout eliminates the energy loss from fork bob during hard pedaling.
26 in Mtb Knobby Tires
Traditional mountain bike tires with a knobby tread pattern in a 1.95 in width. Narrower than fat tires for lower rolling resistance and better efficiency, but with enough tread depth for confident traction on dirt trails, gravel roads, and grass.
Rear Carrier Rack
A welded aluminum carrier over the rear wheel supports panniers, a strapped bag, or camping gear. Rated for approximately 40 lb of distributed cargo. Multiple tie-down points make it easy to secure loads for trail rides or commutes.
Thumb Shifters for Both Derailleurs
Separate thumb shifters control the front triple chainring and the rear 7-speed cassette. The shifters index positively at each gear position so you always know which gear you are in without looking down at the drivetrain.
Padded Comfort Saddle
A wider, padded saddle designed for recreational riding rather than racing. The extra padding and slightly wider platform reduce pressure points on rides longer than an hour, which suits the commuting and touring use this bike is designed for.
Overview
Built for the ride ahead.
The HKM-9720019 uses a lightweight 6061 aluminum diamond frame - the classic mountain bike triangle that offers a strong strength-to-weight ratio for a bicycle frame design. At roughly 48 lb complete with battery, this is one of the lighter e-bikes in the lineup, which makes it easier to lift onto a car rack or carry up apartment stairs. A 350 W geared rear hub motor provides pedal assist up to 20 mph. Geared hubs are more efficient than direct-drive at low speeds and provide better torque for hill climbing relative to their power rating. The 36 V 10.4 Ah lithium pack stores 374 Wh, delivering 30-50 miles of range depending on assist level and terrain. The 21-speed Shimano drivetrain is what sets this bike apart from single-speed and 7-speed e-bikes.
Light, Stiff Alloy Frame
An alloy frame keeps the HKM-9720019 light to lift yet stiff to ride.
The details you never name are the ones you end up trusting the most. The measure of a tool is how little you notice it once the work begins. The HKM-9720019 pairs a 350 W geared brushless rear hub motor, 36 V 10.4 Ah lithium-ion (374 Wh), removable, a range of 30-50 mi (48-80 km), varies by assist and terrain, so it is built for real-world rides rather than showroom specs.
Full Specifications
Measurements are shown in US customary units first, with metric equivalents in parentheses.
Battery, Range, and Charging
Up to 30-50 mi (48-80 km) per charge.
The 36 V 10.4 Ah lithium pack stores 374 Wh of energy. This is a moderate capacity matched to the 350 W motor - enough for 30-50 miles of assisted riding while keeping the pack light and the overall bike weight down to roughly 48 lb. The 21-speed drivetrain is the key to maximizing range on this bike. Riders who use the gears effectively - shifting down for climbs and up for flats - can regularly exceed 45 miles on a single charge because the motor works less when the drivetrain is doing its job. Throttle-only riding at 20 mph returns closer to 25-30 miles.
Daily Use & Care
A short routine keeps the ride quiet and the range where it should be.
Check tire pressure weekly. MTB knobby tires run 30-45 psi for mixed use; lower pressures improve trail grip but increase rolling resistance.
Learn and practice shifting technique. Shift the Shimano rear derailleur under light pedal pressure; ease off completely when shifting the front chainrings.
Lubricate the chain every 150-200 miles. A 21-speed drivetrain has more moving parts and benefits from consistent chain care.
Inspect brake pads monthly and replace when friction material is under 1 mm thick.
Check derailleur alignment periodically. A bent derailleur hanger causes poor shifting across all 21 gears.
Wipe down the frame after wet or muddy rides. Grit in the drivetrain wears chainrings and cassette rapidly.
Remove and store the battery indoors when temperatures approach freezing.
What’s in the Box
Everything needed to get riding, right out of the box.
1 x HKM-9720019 Electric Mountain Bike
1 x HKM-9720019 electric mountain bike
1 x 36 V 10.4 Ah Removable Lithium Battery Pack
1 x 36 V 10.4 Ah removable lithium battery pack
1 x 2 A Smart Charger with 100-240 V Input
1 x 2 A smart charger with 100-240 V input
2 x Battery Keys
2 x Battery keys
1 x Toolkit with Hex Wrenches and Pedal Spanner
1 x Toolkit with hex wrenches and pedal spanner
1 x Pair of Pedals
1 x Pair of pedals
1 x User Manual and Assembly Guide
1 x User manual and assembly guide
1 x Rear Carrier Rack (pre-installed)
1 x Rear carrier rack (pre-installed)
Why Choose the HKM-9720019
6 reasons it earns its place.
True 21-Speed Range
Three chainrings and a 7-speed cassette give you a genuinely wide gear range - low enough for steep climbs, high enough for fast flats. This is a real drivetrain, not a token gear cluster on a bike that expects the motor to do everything.
Lightest Bike in the Lineup
At roughly 48 lb complete, this is the easiest HKM e-bike to lift onto a car rack, carry up stairs, or maneuver in a tight garage. The aluminum diamond frame and moderate battery size are what make that possible.
Trail-Capable Hardtail
An 80 mm lockable fork and 26 in MTB knobby tires handle fire roads, gravel, grass, and smooth singletrack. Lock the fork out and it becomes an efficient road bike for the commute to the trailhead.
Pedal-Forward Design
The 350 W motor is designed to assist your pedaling rather than replace it. Combined with the 21-speed drivetrain, this bike rewards riders who want exercise and efficiency rather than pure throttle-based transportation.
Geared Hub Motor Efficiency
The internal planetary gearing multiplies torque at the speeds where you need it most - climbing hills from a slow start. The internal freewheel also means zero motor drag when you pedal with the assist turned off.
Practical Carrier for Real Trips
The rear rack turns this from a recreational bike into a touring and commuting tool. Carry groceries, a laptop bag, or a weekend camping kit without needing a backpack that makes your back sweat.
Every Component Chosen for Real-World Use
Every component of the HKM-9720019 is chosen for real-world use.
It is built to be ridden regularly, cleaned easily, and kept in top condition with routine care. The HKM-9720019 pairs a 350 W geared brushless rear hub motor, 36 V 10.4 Ah lithium-ion (374 Wh), removable, a range of 30-50 mi (48-80 km), varies by assist and terrain, so it is built for real-world rides rather than showroom specs.
Controls & Indicators
What each control on the HKM-9720019 does.
Power Button
Hold the button on the battery pack to switch the system on or off
Mode Buttons
Up/down buttons on the LCD cycle through pedal-assist levels
Thumb Throttle
Right-hand thumb lever; proportional response independent of pedals
Speedometer
Numeric speed readout in mph on the backlit LCD
Battery Gauge
Segment indicator showing remaining charge on the LCD
Headlight Button
Long-press the up button to toggle the LED headlight
Dual Shifters
Left thumb shifter for the front triple chainring, right for the 7-speed cassette
Frequently Asked Questions
Quick answers about the HKM-9720019.
Why 21 speeds instead of the more common 7?
The three front chainrings triple your gear options. This gives you very low gears for steep climbing and very high gears for fast flat-ground riding. With 7 speeds you compromise at both ends. The wide range also lets you extend battery range by pedaling efficiently in the right gear rather than relying on the motor.
Is 350 W enough power for hills?
Yes, for moderate hills up to about 15 degrees with a solo rider. The geared hub motor multiplies torque at low speeds, which helps on climbs. On steeper grades you will need to shift to a low gear and pedal to assist the motor - which is exactly what the 21-speed drivetrain is designed for.
How do I shift a triple chainring correctly?
Use the front shifter for major terrain changes: small ring for climbing, middle ring for general riding, large ring for flats and descents. Use the rear shifter for fine adjustments within each range. Ease off pedal pressure momentarily when shifting the front derailleur.
What is the realistic range?
Plan for 30-50 miles. Throttle-only at 20 mph returns 25-30 miles. Moderate pedal-assist with effective gear use regularly delivers 40-50 miles. Steep terrain, headwinds, cold weather, and heavy cargo all reduce range.
Can I use this on singletrack mountain bike trails?
This is a hardtail with 80 mm of front travel and 1.95 in tires - suitable for smooth to moderate singletrack, fire roads, and gravel. It is not designed for technical downhill or rocky terrain that requires full suspension and wider tires.
How much does the bike weigh and can I lift it?
Approximately 48 lb with the battery installed, or 43 lb with the battery removed. That is light enough for most adults to lift onto a car rack or carry short distances, and notably lighter than fat tire or full-suspension e-bikes.
Is the rear carrier strong enough for grocery panniers?
Yes. The carrier is rated for approximately 40 lb of distributed weight, which handles a full pair of grocery panniers or camping gear for a weekend trip. Distribute weight evenly between both sides for confident handling.
What maintenance does the 21-speed drivetrain need?
Keep the chain clean and lubricated every 150-200 miles. Check derailleur adjustment if shifting becomes imprecise. Inspect chainrings and cassette for tooth wear annually. A well-maintained 21-speed drivetrain shifts crisply for thousands of miles.
Quick Troubleshooting
Common issues and what to check first.
The chain will not shift onto the largest front chainring.
The front derailleur high limit screw may need adjustment, or the cable tension is too low. Turn the barrel adjuster counterclockwise a half turn to increase tension. If that does not help, adjust the high limit screw outward slightly.
The chain drops off the chainrings when shifting.
The front derailleur limit screws are likely set incorrectly. The derailleur cage should sit 1-3 mm above the largest chainring teeth and parallel to the rings. Have a mechanic set the limits if you are not comfortable adjusting them.
Shifting is imprecise or the chain hesitates between gears.
Cable tension is the usual culprit. Turn the barrel adjuster a quarter turn at a time while shifting through the cassette until each gear engages cleanly. A bent derailleur hanger also causes this symptom and requires straightening or replacement.
The motor feels weak on hills compared to when new.
Check the battery charge level and tire pressure first. Then verify you are shifting to a low gear on climbs - the geared hub motor produces strong torque at lower wheel speeds when the drivetrain is doing part of the work.
The fork does not lock out or feels stuck.
Check that the lockout lever is fully rotated to the locked position. If the fork still compresses when locked, the internal lockout mechanism may need service. Have a qualified shop inspect and service the fork.
The display shows an error code and the motor will not engage.
Power off, wait 30 seconds, and restart the system. Verify the battery is fully seated and both brake levers are released. If the code persists, note it exactly and contact support.
Certifications & Standards
Documented and tested for sale.
CE
European Conformity (CE) marking where applicable for the safety and electrical assembly.
ISO 9001
Quality management system held by the manufacturing facility.
Compliance Docs
Safety and compliance documentation included with every unit on request.
Tested
Each unit is inspected and function-tested before it leaves the warehouse.
From Frame to Wheels
From the frame to the wheels, the HKM-9720019 is built for consistent, confident performance.
The specifications above show exactly what is under the surface, and the ride proves it every time. The HKM-9720019 pairs a 350 W geared brushless rear hub motor, 36 V 10.4 Ah lithium-ion (374 Wh), removable, a range of 30-50 mi (48-80 km), varies by assist and terrain, so it is built for real-world rides rather than showroom specs.
Pre-Ride Safety Checklist
Run through these before every ride.
Check tire pressure: 30-45 psi for mixed use, lower for loose trail surfaces.
Shift through all 21 gears while the bike is on a stand to verify smooth, precise shifting.
Squeeze both brake levers and confirm they firm up well before reaching the grip.
Verify the battery is locked in place and the display shows expected charge.
Check that the fork lockout lever moves freely and the fork compresses smoothly when unlocked.
Confirm quick-release levers, axle nuts, and the carrier rack bolts are tight.
Test the throttle at walking speed in a clear area, and always wear a helmet.
Service & Policies
Every HKM-9720019 is backed by coverage designed to protect your investment.
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.
Important Safety Notes
Read before the first ride.
This 350 W bike is rated at 20 mph. Read the manual first and practise throttle and braking in an open, traffic-free area. Leave extra room for braking, since stopping distance grows fast with speed and load. Wear a helmet every ride. Do not exceed the 265 lb (120 kg) load limit, including rider, cargo, and rack load. Confirm local law before riding on public roads. Bed the brakes in with 10-15 progressive stops over the first rides. Never ride through water deep enough to reach the motor or battery. Charge only with the supplied charger, indoors and attended. Never open, puncture, or modify the pack. Slow down substantially on gravel, wet surfaces, and steep descents.
HKM-9720019 - Electric Mountain Bike. Specifications are for reference; actual performance varies with rider, terrain, tire pressure, and temperature. This page describes the product only and is not legal advice regarding vehicle classification - confirm local regulations before riding on public roads.
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.
We believe in the quality of our products, and we want you to share that confidence. Every product is backed by a 24-month warranty covering all structural and functional components, including zippers, buckles, straps, and fabric integrity.
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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Delivery Time Summary
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Start claims or returns quickly and easily.
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Step-by-step solutions for product issues.
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
