Balance Bikes >>
HKM-5639763 16 Inch Electric Balance Bike FXB03-16 Ages 5-14, 350W Brushless Motor 36V Hot-Swap Battery and Leather Saddle
HKM-5639763
The Comfort Upgrade for Young Riders
The FXB03-16 is the balance bike that treats comfort as a feature, not an afterthought: an ergonomically contoured genuine leather saddle, a 36V 350W brushless motor with quiet gearbox-integrated power, and hot-swappable batteries in 2.5Ah or 5.0Ah that recharge in 30-60 minutes. Dual speed modes grow with riders aged five to fourteen, the brake-triggered motor cut-off and non-slip platforms keep them safe, and the 16 x 2.125 all-terrain air tires carry it all from pavement to packed dirt.
Key Features
Six details that define the HKM-5639763.
Genuine Leather Saddle
The saddle is ergonomically contoured with a soft genuine leather cover that breathes better than synthetics, staying cooler in summer. It reduces fatigue on longer rides and supports a natural upright posture that aids balance.
36V 350W Brushless Motor
The gearbox-integrated brushless motor delivers quiet, efficient power with minimal maintenance. The twist-grip throttle responds progressively, with no jerky starts, and assists in proportion to the rider's own input.
Hot-Swap Battery Options
Choose 2.5Ah for lighter rides or 5.0Ah for extended adventure, and swap packs in seconds. Rapid 30-60 minute charging gets young riders back outside fast, minimizing the downtime between sessions.
Brake-Triggered Motor Cut-Off
An automatic motor cut-off engages the moment the brake is applied, an elegant safety net for learners. Add the low center of gravity and non-slip foot platforms, and the bike feels planted from the first ride.
All-Terrain 16-Inch Tires
The 16 x 2.125 pneumatic tires absorb bumps from pavement, grass and packed dirt, while the wide 82 cm wheelbase plants the bike confidently and reduces tip-over risk during quick turns.
Built for Ages 5-14
Adjustable speed modes and the 54 cm saddle height suit a wide age range, meaning years of use before outgrowing it. Reflective rim strips and an LED-ready housing add visibility for dusk rides.
Overview
A 16-inch FXB03-16 with a leather saddle, hot-swap battery and 350W brushless motor, for ages 5-14.
The FXB03-16 merges intuitive balance training with a smooth electric boost, dressed in quality. The genuine leather saddle contours to young riders and breathes better than synthetic covers, while the 36V 350W brushless motor with gearbox integration delivers quiet power through a progressive twist-grip throttle. Batteries in 2.5Ah or 5.0Ah swap in seconds and recharge in 30-60 minutes. Safety is complete: brake-triggered motor cut-off, a low center of gravity, non-slip foot platforms, reflective rim strips and an enclosed chainless drivetrain. With dual speed modes, 16 x 2.125 all-terrain air tires and a 54 cm saddle on a wide 82 cm wheelbase, it is the smart step toward two-wheeled freedom for riders aged five to fourteen.
Comfort That Teaches
A better seat makes a better rider.
The leather saddle keeps young riders fresh, and fresh riders practice longer. Add the progressive throttle, the quiet brushless motor and the hot-swap battery, and practice becomes the favorite part of the day.
Full Specifications
Everything worth knowing, in one table.
Swap the Battery, Not the Plans
Two packs in seconds, thirty minutes to full.
Every kids' bike has a downtime problem, and the FXB03-16 solves it twice. First, the batteries are hot-swappable: a 2.5Ah pack for lighter rides or a 5.0Ah pack for extended adventure, exchanged in seconds without tools. Second, rapid charging takes just 30-60 minutes, so even a single pack is ready before the snack break ends. That endurance sits on a quality platform: a 36V 350W gearbox-integrated brushless motor with progressive twist-grip response, a genuine leather saddle that breathes and supports good posture, and 16 x 2.125 all-terrain air tires on a wide 82 cm wheelbase. The brake-triggered motor cut-off, non-slip platforms and enclosed chainless drivetrain close the safety loop for riders aged five to fourteen.
What’s in the Box
What arrives in the box, ready to build.
1 x 16-Inch FXB03-16 Balance Bike
Frame, fork and wheels come fitted from the box
1 x Hot-Swap Lithium Battery
Seated in the mount and matched to the charger
1 x Mains Charger
Matched to the battery pack from the factory
1 x Seat and Post
Fitted, ready to set for the height of the rider
1 x Manual and Hex Keys
Setup sheets with the tools supplied in the pack
1 x Warranty Card
Registration details for the records at home
Why Choose the HKM-5639763
Six reasons families pick the HKM-5639763.
A Saddle Worth Sitting On
Genuine leather, ergonomically contoured and breathable, the saddle reduces fatigue and supports the upright posture that balance learning needs. Small detail, enormous difference over a summer.
Battery Days Without Waiting
Hot-swappable packs in 2.5Ah or 5.0Ah change in seconds, and 30-60 minute charging is among the fastest around. More riding, less waiting, fewer negotiations at the door.
Smooth Where It Matters
The progressive twist-grip throttle and 36V 350W brushless motor respond in proportion to the rider, with no jerky starts. Confidence is built on smoothness, and this bike knows it.
Safety as a System
Brake-triggered motor cut-off, a low center of gravity, non-slip platforms, reflective rim strips and an enclosed chainless drivetrain: the safety features work together, not as a checklist.
Planted and Predictable
The wide 82 cm wheelbase and 16 x 2.125 all-terrain air tires keep the bike stable through quick turns and across pavement, grass and packed dirt. Predictable is how beginners describe fun.
Years, Not Seasons
Adjustable speed modes and a saddle height that suits ages five to fourteen mean the bike stays relevant for years. The rugged alloy frame shrugs off scratches and weather along the way.
Frequently Asked Questions
Straight answers about the HKM-5639763.
What ages does the FXB03-16 suit?
The bike is designed for kids aged five to fourteen, with a 54 cm saddle height that accommodates most children in that range and adjustable speed modes that keep the pace appropriate as they grow. Judge the final fit physically: both feet flat while seated, knees slightly bent, hands on the bars at comfortable extension. And because the motor assists in proportion to the rider's own input, the skills carry over cleanly: children who learn on balance bikes typically move to pedal bikes up to six months earlier than peers who start on training wheels.
How do the hot-swap batteries work?
The battery packs are tool-free and hot-swappable, changing in seconds: choose the 2.5Ah pack for lighter rides or the 5.0Ah pack for extended adventure. Many families run the smaller pack as the charged spare. The packs charge rapidly, reaching full in 30-60 minutes, which is among the quickest in the class.
What makes the throttle safe for beginners?
The twist-grip throttle uses progressive response, so power arrives smoothly with no jerky starts, and the motor assists in proportion to the rider's own input. When the brake is applied, an automatic motor cut-off engages instantly. Together with the low center of gravity, these systems keep the first powered rides calm and controlled.
Is the leather saddle actually practical for kids?
Yes: genuine leather breathes better than synthetic covers, staying cooler in summer, and the ergonomic contour supports a child's posture for natural, balanced positioning. It reduces fatigue on longer rides, which means longer practice sessions, and the surface cleans with the same care as any leather good.
What terrain can it handle?
The 16 x 2.125 all-terrain pneumatic tires absorb bumps from pavement, grass and packed dirt, and the wide 82 cm wheelbase keeps the bike planted through quick turns. Loose sand and steep technical trails remain beyond any bike in this class, so treat those as walk-arounds and save the trails for the pedal years. A quick tire-pressure check before each session keeps the ride as smooth as the day it was set up.
What assembly and upkeep are involved?
Setup covers the handlebar, saddle height and a battery charge check with the supplied tools and manual. Beyond that: tire pressure weekly, a brake check before rides and a wipe-down after dusty ones. The enclosed chainless drivetrain keeps fingers and clothing safe from moving parts and removes chain maintenance entirely.
Quick Troubleshooting
When the HKM-5639763 needs attention, start here.
The bike will not power on
Confirm the battery pack has charge and is fully seated, because a hot-swap pack just short of home makes no contact. Press the power button and watch for the indicator. If it stays dark, connect the charger for twenty minutes and retry, and inspect the mount contacts for grit. If everything looks clean and the bike stays dead, note the details and contact support.
The run time keeps shrinking
Compare riding style first, because the high-speed mode and hills use far more per minute than cruising. Check tire pressure, since soft tires cost range twice. Cold weather trims every lithium pack. If nothing has changed, run one full uninterrupted charge and retest the same loop on the same mode, and log the loop you retest on before replacing anything.
The brake or cut-off feels inconsistent
The brake-triggered motor cut-off should engage the instant the lever moves, so treat any delay as a fault. Check the lever and cable for stretch and grit, and confirm the connector at the brake is fully seated. Do not ride if the cut-off is unreliable. If the behavior continues after the cable is set, note when it started and contact support.
The charger light never turns green
Confirm the wall socket with another device, then reseat the charger plug at both the wall and the pack. Charge indoors at room temperature, because cold packs refuse a full cycle, and check the contacts for grit or bent pins. Stick to the supplied charger, since adapters with different outputs can hold the indicator short of green. If the indicator still never completes, stop forcing cycles and contact support. Do not leave a stalled charge unattended overnight.
The motor cut out mid-ride
A battery running low or hot will step back before it dies, so start with a full charge and a cool-down. Confirm the speed mode has not been nudged, and swap to the spare pack if one is charged to rule out the pack itself. A soaking from deep puddles can also trip protection, so let the bike dry fully before the next start. If cutouts continue on flat ground with a full, cool pack, note the mode in use and contact support.
The pace feels reduced
First confirm which speed mode is selected, because the most common cause is simply riding in the learner mode. Next check tire pressure, since soft tires sap performance long before the motor does. A low battery also steps the support back to protect itself. If the bike still feels flat with fresh tires and a full charge, note the details and contact support.
Service & Policies
Coverage that rides every road with you.
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 these notes before the first ride on the HKM-5639763.
The HKM-5639763 is a 16-inch-wheel electric balance bike for riders aged five to fourteen, so a certified helmet is mandatory before every ride, with closed shoes completing the kit. Start in the low-speed mode on flat, open ground until the rider has the brake and the throttle under smooth control, with an adult approving every change. Confirm the hot-swap pack is fully seated before each ride, test the brake for the bite and the cut-off for its response, and check the axle and stem hardware for torque. Keep fingers, laces and loose clothing away from the enclosed drivetrain, and let hot parts cool after sessions. Charge the pack indoors at room temperature on a hard surface, unplug once full, and never carry a passenger.
HKM-5639763 - FXB03-16 16-inch electric balance bike for ages 5-14 with a 36V 350W brushless gearbox-integrated motor, dual adjustable speed modes, hot-swappable 2.5Ah or 5.0Ah batteries charging in 30-60 minutes, a genuine leather saddle, all-terrain tires and a brake-triggered motor cut-off. Read the manual before first use. Nothing here is safety certification advice.
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.
Our return policy is built on a simple principle: if the product is not right for you, we will make it right. We understand that online shopping involves trust, and we work hard to earn that trust with every order.
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
Every order ships free—no minimums, no hidden fees. We currently deliver across the United States and are actively working to expand to more countries. We partner with reliable U.S. courier services to ensure your order arrives safely and on time.
Our delivery process is designed for transparency. From the moment you place your order to the moment it reaches your door, you receive clear updates at every stage. We carefully inspect each product before dispatch, and we provide tracking information as soon as your order ships.
Our U.S. Shipping Partners
USPS
Official national carrier with nationwide coverage.
UPS
Fast and reliable ground and express shipping.
FedEx
Express delivery with real-time tracking.
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Efficient parcel delivery for e-commerce shipments.
Delivery Process
Delivery Time Summary
Cancellations & Taxes
You may cancel your order at any time before it ships. All product prices include applicable taxes, and there are no additional VAT or customs fees for orders delivered within the United States.
Whether you have a question, need help with an order, or just want some advice, our support team is available around the clock. We don't just respond to messages—we work with you to find real solutions that fit your needs.
Our support specialists are trained to handle a wide range of requests, from product recommendations to technical troubleshooting. No matter the question, you can expect a professional and friendly response.
How We Can Help
Product Guidance
Our experts help you choose the right product.
Order Assistance
Modify orders, track shipments, or speed up delivery.
Warranty & Returns
Start claims or returns quickly and easily.
Technical Troubleshooting
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
