1. Introdución
This manual provides detailed instructions for the installation, operation, and maintenance of your Varstrom 500W Electric Bike Conversion Kit, specifically for the Vd04 model with a 26-inch wheel. This kit is designed to transform a standard bicycle into an electric bicycle, offering enhanced performance and versatility for city commuting, mountain biking, delivery, and cargo transport. Please read this manual thoroughly before installation and use to ensure proper function and safety.
2. Información de seguridade
Always prioritize safety when installing and operating your e-bike conversion kit.
- Wear a helmet and appropriate safety gear when riding.
- Asegúrate de que todas as conexións estean seguras e sexan impermeables antes de conducir, especialmente en condicións de humidade.
- Regularly inspect your bicycle and the conversion kit components for wear, damage, or loose parts.
- Familiarize yourself with local e-bike regulations and laws.
- Do not attempt to modify the motor or controller, as this may void the warranty and create safety hazards.
- Keep hands and clothing clear of moving parts, especially the motor and wheel spokes.
- Always turn off the power before performing any maintenance or adjustments.
3. Contido do paquete
The Varstrom 500W Electric Bike Conversion Kit includes the following components:

Figura 3.1: Acabadoview of the comprehensive assembly kit components.
This image displays the complete set of components included in the Varstrom 500W Electric Bike Conversion Kit. It shows a motor with rim, an LCD display, a controller, a controller case, a thumb throttle, brake levers, a standard left PAS sensor, a 1T4 waterproof cable, and a user manual.
- 1 x Rear Hub Motor with Rim (26-inch wheel)
- 1 x LCD Display (VD04 model)
- 1 x controlador
- 1 caixa de controlador
- 1 x Acelerador de polgar
- 1 par de palancas de freo
- 1 x Left PAS Sensor
- 1 x 1T4 Waterproof Cable
- All necessary cables and mounting hardware
- 1 x Manual de usuario
4. Especificacións
Key technical specifications for the Varstrom 500W Electric Bike Conversion Kit:

Figura 4.1: Detailed motor specifications.
Esta imaxe ofrece unha visión completaview of the motor's technical specifications. It highlights a maximum speed of 58 km/h (36 mph), maximum torque of 65 N.m, maximum controller current of 18A, rated voltage of 48V, rated power of 500W, and compatibility with Disc/V brakes. It also specifies the geared brushless rear hub motor's installation width of 142mm (5.59"), 12G silver spokes with double wall rim for 20"/26"/27.5"/28"/29"/700C, and a 500mm cable with quick release waterproof connector. Compatible rear dropout is 138-145mm (5.43-5.71") and fork notch width is 10mm (0.39"). The disc brake diagonal hole distance is 44mm (1.73") and adjacent hole distance is 22mm (0.86"). It explicitly states compatibility with cassette freewheel and incompatibility with standard freewheel.

Figura 4.2: Wheel and motor size specifications.
This image details the size specifications of the motor and wheel. It shows a motor diameter of 166mm, an axle length of 204.5mm, and a compatible rear dropout size of 138-145mm. The rim diameter is specified for 20" (420mm), 26" (571mm), 27.5" (596mm), and 700C (634mm). Compatible rim diameter is 1.5-2.4" and spoke specification is 36H*12G.
| Característica | Especificación |
|---|---|
| Marca | Varstrom |
| Nome do modelo | 125XVH 48V 500W RDC |
| Voltage | 48 voltios |
| Wattage | 500 vatios |
| Velocidade máxima | 58 km/h (36 mph) |
| Par máximo | ≥65 N.m |
| Velocidade sen carga | 415 RPM |
| Material | Aluminio |
| Clasificación impermeable | IPX5 |
| Tamaños de rodas compatibles | 20", 26", 27.5", 28", 29", 700C |
| Lonxitude do eixo traseiro | 204.1 mm |
| Dropout Spacing | 138-145 mm |
| Compatibilidade de casetes | ≤10-speed cassettes |
| Modelo de visualización | VD04 (3.5-inch IPS, Navigation, Multi-language, Quick switch to 25km/h) |
5. Configuración e instalación
Installation of the Varstrom e-bike conversion kit requires basic mechanical skills and tools. It is recommended to consult a professional bicycle mechanic if you are unsure about any steps.
5.1 Comprobacións previas á instalación
- Ensure your bicycle's rear dropout spacing is between 138-145mm.
- Verify your bicycle's wheel size matches the kit (26 inches for this model).
- Confirm your cassette is compatible (≤10-speed).
- Gather all necessary tools (e.g., wrenches, screwdrivers, cable ties).
5.2 Pasos de instalación (Información xeral)view)
- Remove Rear Wheel: Carefully remove your bicycle's existing rear wheel.
- Instalar a roda motora: Mount the new motor wheel into the rear dropouts, ensuring it is centered and secured with axle nuts.
- Controlador de montaxe: Secure the controller and controller box to the bicycle frame, typically near the seat tube or down tube.
- Instalar o sensor PAS: Attach the left Pedal Assist System (PAS) sensor to the crank arm, ensuring proper alignment with the magnet disc (if separate).
- Install Display and Throttle: Mount the VD04 LCD display and thumb throttle on the handlebars in a comfortable and accessible position.
- Install Brake Levers: Replace your existing brake levers with the provided e-bike specific brake levers, which include motor cut-off switches.
- Conectar cableado: Connect all components using the provided waterproof cables. Ensure each connector is fully seated and secured. The 1T4 waterproof cable simplifies connections.
- Xestión de cables Route and secure all cables neatly along the frame using cable ties to prevent snagging or damage.
- Comprobacións finais: Before riding, perform a thorough check of all connections, brake function, and wheel alignment.

Figura 5.1: Visual guide for connecting the upgraded controller to various components.
This image illustrates the upgraded sine wave controller and its various connections to the e-bike components. It shows the controller connected to the motor wheel, battery, display, throttle, PAS sensor, and brake levers. The image also highlights the importance of using the correct PAS sensor for hollow crank sets.
6. Instrucións de funcionamento
Once installed, operating your Varstrom e-bike kit is straightforward.
6.1 Acendido/Apagado
- To power on the system, press and hold the power button on the VD04 LCD display.
- Para apagar, manteña premido o botón de acendido de novo.
6.2 VD04 LCD Display Functions

Figura 6.1: VD04 LCD Display interface and specifications.
This image showcases the VD04 LCD display, highlighting its 3.5-inch IPS screen, dimensions (89.3mm x 60.8mm x 6.4mm), and various functionalities. It displays speed (KM/H or MPH), trip distance, odometer, average speed, power output, and battery level. The display also features navigation, multi-language support, and a quick switch to 25km/h. Speed limit settings range from 1 to 99 km/h, handlebar mounting diameters are 22.2mm/25.4mm/31.8mm, assist levels are 3, 5, or 9, and it includes a Type-C 5V 1A USB port for charging.
The VD04 display provides essential riding information and control:
- Velocidade: Current speed displayed in KM/H or MPH.
- Nivel de batería: Indica a carga restante da batería.
- Nivel de asistencia: Adjust pedal assist levels (3, 5, or 9 levels available) using the '+' and '-' buttons.
- Trip/ODO: View current trip distance or total odometer reading.
- Navegación: The VD04 display supports navigation features.
- Multi-idioma: Supports multiple languages for user convenience.
- Límite de velocidade: Quick switch to 25 km/h speed limit.
- Carga USB: Features a Type-C 5V 1A USB port for charging external devices.
6.3 Modos de condución

Figura 6.2: Illustration of the four available riding modes.
This image depicts a cyclist riding an e-bike and highlights the four distinct riding modes available with the Varstrom kit: Throttle, PAS (Pedal Assist System), Manual, and Boost.
- Modo acelerador: Engages the motor directly via the thumb throttle, providing power without pedaling.
- Modo PAS (Sistema de asistencia ao pedaleo): O motor proporciona asistencia mentres pedaleas. O nivel de asistencia pódese axustar a través da pantalla.
- Modo manual: Anda en bicicleta coma se fose unha bicicleta tradicional sen axuda de motor.
- Modo de aumento: Provides maximum motor power for quick acceleration or climbing steep inclines.

Figura 6.3: Varstrom 125XVH motor performance.
This image shows a person riding an e-bike, emphasizing the powerful performance of the 125XVH motor. Key performance metrics are displayed: 58 km/h (36 mph) max speed, 415 RPM high speed, and ≥65 N.m high torque.
7. Mantemento
Regular maintenance ensures the longevity and safe operation of your Varstrom e-bike conversion kit.
- Limpeza: Limpar o motor, o controlador e a pantalla con publicidadeamp pano. Evite lavar a alta presión directamente sobre os compoñentes eléctricos.
- Conexións: Periodically check all electrical connections for tightness and corrosion. Ensure waterproof connectors are properly sealed.
- Freos: Inspect brake pads and rotors for wear. Adjust or replace as necessary. Ensure the motor cut-off function of the brake levers is working correctly.
- Pneumáticos: Maintain proper tire pressure and inspect for wear or damage.
- Cadea e transmisión: Keep the chain clean and lubricated. Check for wear on the cassette and chainring.
- Coidado da batería: Follow the battery manufacturer's instructions for charging, storage, and maintenance. Avoid fully discharging the battery.
- Motor: The 125XVH hub motor is designed to be maintenance-free for up to 100,000 kilometers.
8 Solución de problemas
Se tes problemas co teu kit de bicicleta eléctrica, consulta os seguintes pasos comúns para a resolución de problemas:
| Problema | Causa posible | Solución |
|---|---|---|
| O motor non se conecta | Loose electrical connection, low battery, brake lever engaged, PAS sensor issue. | Check all connections, charge battery, ensure brake levers are fully released, inspect PAS sensor for proper alignment. |
| A pantalla non se acende | Loose power cable, dead battery. | Check display cable connection to controller, ensure battery is charged and connected. |
| Potencia/alcance reducido | Low battery charge, battery degradation, incorrect assist level. | Fully charge battery, consider battery replacement if old, increase assist level. |
| Ruídos pouco comúns do motor | Loose components, internal motor issue. | Check for loose spokes or other components. If noise persists, contact customer support. |
For further assistance, please contact Varstrom customer support.
9. Garantía e soporte
Your Varstrom Electric Bike Conversion Kit comes with the following warranty and support:
- Devolucións: 30-day free returns.
- Reparación: 1-year free repair service.
- Consulta: Lifetime after-sales consultation.
For warranty claims or technical support, please refer to the contact information provided with your purchase or visit the official Varstrom websitio.