1. Setup and Assembly
Carefully unpack and assemble your HAPPYRUN G50 Electric Bike by following these steps. It is recommended to have a clean, open workspace.
1.1 Unboxing and Initial Inspection
Remove the electric bike from its packaging. Inspect all components for any signs of damage during transit. Ensure all parts listed in the packing list are present.
Video: Happyrun Unboxing and Assembly. This video demonstrates the unboxing process and initial assembly steps for the HAPPYRUN G50 Electric Bike.
The video above provides a visual guide for unboxing and assembly. Pay close attention to the packaging removal and component identification.
1.2 Handlebar Installation
Attach the handlebars to the stem. Ensure they are centered and aligned correctly before tightening the bolts securely using the provided M5 Allen wrench. Adjust to a comfortable riding position.

Image: Excellent Shifting Performance. This image shows the 7-speed thumb shifter and 7-speed cassette with rear derailleur, which are part of the handlebar assembly.
1.3 Front Wheel and Fender Attachment
Install the front wheel into the fork. Ensure the disc brake rotor is correctly seated within the caliper. Attach the front fender using the provided hardware. Secure all bolts firmly.

Image: Front wheel and fender. The image displays the front wheel with its fat tire and fender, ready for installation.
1.4 Pedal Installation
Identify the left (L) and right (R) pedals. Thread the pedals into their respective crank arms. The left pedal threads counter-clockwise, and the right pedal threads clockwise. Tighten them securely with a wrench.
1.5 Battery Installation and Connection
Insert the 48V 18Ah lithium battery into its housing on the bike frame. Ensure it clicks securely into place. Connect any necessary power cables as indicated in the manual. The battery is removable for convenient charging.

Image: Removable Long-Lasting Battery. This image highlights the 48V 18Ah battery with BMS protection, offering up to 68 miles range.
1.6 Tire Inflation
Inflate both 20" x 4.0" fat tires to the recommended pressure, typically around 20 PSI, as indicated on the tire sidewall. Use a bicycle pump with a pressure gauge.

Image: 20x4.0" All-Terrain Fat Tires. This image showcases the robust fat tires suitable for various terrains including urban, trail, sand, and snow.
2. Operating Instructions
Familiarize yourself with the controls and riding modes for optimal performance and safety.
2.1 Power On/Off and Display
To power on the bike, press and hold the power button on the LCD display. The intuitive LCD digital display will show speed, mileage, battery level, and current mode. Press and hold again to power off.

Image: LCD Central Display. The display shows speed, riding time, mileage, and remaining battery, with IPX4 water resistance and 3 modes.
2.2 Riding Modes
The HAPPYRUN G50 offers three working modes:
- Riding Mode: Standard pedal cycling without electric assist.
- PAS Mode (Pedal Assist System): Provides electric assistance while pedaling, extending range up to 68 miles.
- Pure Electric Mode: Uses the throttle for full electric power, offering a range of up to 30 miles.

Image: 3 Modes Meet Different Needs. This graphic explains the Riding Mode, PAS Mode (68+ Miles), and Pure Electric Mode (30+ Miles).
2.3 Shifting Gears
Utilize the Shimano 7-speed gear shift system to adapt to different terrains and riding conditions. Shift gears smoothly to maintain an efficient pedaling cadence.

Image: Excellent Shifting Performance. This image shows the 7-speed thumb shifter and 7-speed cassette with rear derailleur.
2.4 Braking System
The bike is equipped with disc brakes for reliable stopping power. Apply both front and rear brakes gently and evenly to slow down or stop. Avoid sudden, hard braking, especially with the front brake, to prevent loss of control.
3. Maintenance
Regular maintenance ensures the longevity and safe operation of your electric bike.
3.1 Battery Care
- Charge the battery fully before first use and after every ride.
- Do not completely drain the battery.
- Store the battery in a cool, dry place when not in use.
- Avoid exposing the battery to extreme temperatures.
3.2 Tire Pressure
Check tire pressure regularly before each ride. Maintain the recommended pressure (approx. 20 PSI) for optimal performance and to prevent punctures.
3.3 Cleaning and Storage
- Clean the bike with a damp cloth and mild soap. Avoid high-pressure washing directly on electrical components.
- Store the bike in a dry, secure location, away from direct sunlight and extreme weather conditions.
3.4 Brake and Gear Inspection
Periodically inspect brake pads for wear and ensure brake levers are responsive. Check the gear system for smooth shifting and proper chain tension. Adjust as needed or consult a professional.
4. Troubleshooting
This section provides solutions to common issues you might encounter.
4.1 Bike Not Powering On
- Ensure the battery is fully charged and properly installed.
- Check that the battery is securely locked into the frame.
- Verify all electrical connections are firm and undamaged.
4.2 Motor Not Assisting
- Confirm the bike is in PAS mode or Pure Electric mode.
- Check the battery level on the display.
- Ensure the brake levers are not partially engaged, as this can cut motor power.
4.3 Unusual Noises
- Inspect the chain for proper lubrication and tension.
- Check for loose components, especially around the wheels, pedals, and handlebars.
- Examine brake rotors and pads for rubbing or misalignment.
5. Specifications
| Model Name | HR-G50 |
| Bike Type | Electric Bike |
| Motor | 1500W (Peak) Brushless Gear Motor |
| Battery | 48V 18Ah Removable Lithium Battery |
| Top Speed | 32 MPH |
| Range (Pedal Assist) | Up to 68 miles |
| Range (Pure Electric) | Up to 30 miles |
| Gears | Shimano 7-Speed Derailleur |
| Tires | 20" x 4.0" Puncture Resistant Fat Tires |
| Suspension | Dual Shock Absorber (Front Fork & Seat) |
| Frame Material | Carbon Steel |
| Brake Style | Disc |
| Maximum Weight Recommendation | 265 Pounds |
| Item Weight | 95 Pounds |
| Special Feature | Digital Display |

Image: Bike Weight and Load Capacity. This graphic provides key dimensions and weight limits for the bike.
6. Warranty and Support
HAPPYRUN offers a 1-Year Warranty against manufacturer defects. For any queries or support, please contact our customer service team. We aim to respond within 24 hours.
Please retain the original packaging for at least one month in case of a return.