135mm Automatic 3 Gear Hub Belt Drive Internal Gear Hub For Premium E Bikes

The LG-N7122-3D is the belt-drive version of the A03 automatic 3-speed internal gear hub series, developed for city e-bikes and premium commuter bicycles that need a cleaner, quieter and lower-maintenance drivetrain. Its main difference is the 57 mm G1 chainline and matching 9-tooth belt cog with 6.2 mm slot, making it suitable for frame platforms designed around belt drive systems.

Recommended image position: use the dedicated LG-N7122-3D product image after the overview.

Using CentriGear automatic mechanical shifting, the hub changes gears through centrifugal force and planetary gear transmission. Riders can start, cruise and handle moderate city slopes without manual shifting, while the sealed hub body protects the internal transmission mechanism from dust, mud and rainwater.

• Automatic Mechanical Shifting: Shifts between three gears without manual operation.
• Belt Drive Compatibility: Designed for clean, quiet and low-maintenance belt drive e-bike systems.
• 166% Gear Range: Supports smooth starting, efficient cruising and moderate climbing.
• CentriGear Technology: Uses centrifugal force and planetary gears for automatic gear transitions.
• Sealed Hub Structure: Helps protect internal parts from dust, water and road contamination.
• 6-Bolt Disc Brake Support: Compatible with modern disc brake city e-bike platforms.
• 57 mm Chainline: Suitable for specific belt drive frame and drivetrain layouts.
• Low-Maintenance Riding: Reduces exposed drivetrain adjustment and routine service.

This automatic internal gear hub uses a mechanical centrifugal shifting mechanism. As the riding speed increases or decreases, the internal structure responds automatically and shifts between three gear ratios: 1.00, 1.29 and 1.66. This allows the rider to focus on pedaling without selecting gears manually.

The LG-N7122-3D version is especially suitable for belt drive e-bike designs that require a wider chainline layout. Its 57 mm G1 chainline and matching 9-tooth belt cog with 6.2 mm slot make it a practical option for urban frames designed around clean, quiet and low-maintenance drivetrain systems. Because the transmission components are sealed inside the hub shell, the product helps reduce exposure to road dirt and weather conditions, supporting more stable long-term use.

• Automatic 3-speed internal gear hub for belt drive city e-bikes.
• No manual shifter required for regular riding.
• Sealed structure for improved durability and lower maintenance.
• 6-bolt disc brake interface for urban e-bike brake systems.
• 135 mm O.L.D. and 184 mm axle length.
• 57 mm G1 chainline for specific belt drive configurations.
• 9-tooth belt cog with 6.2 mm slot.
• Black finish for integrated premium e-bike appearance.

This model is suitable for belt drive city e-bikes, urban commuter bicycles and low-maintenance electric bicycle platforms. It is especially useful for OEM projects that require a clean frame appearance, quiet drivetrain operation and simplified daily riding experience. The automatic shifting structure helps reduce rider operation, while the sealed hub design supports stable use in city commuting, leisure riding and short-distance mobility scenarios.

Before sampling, OEM customers should confirm frame O.L.D., belt-line, belt cog matching, brake interface, axle compatibility and wheel specification. Lofandi can support drawing confirmation, belt-drive matching review, sample preparation and project validation.