The Bafang BBS02 M315 36V 500W (reference MM G340.500.C) is one of the most popular and reliable mid-drive motors on the electric conversion market. With its maximum torque of 100 N.m and its rated power of 500W, this geared central motor transforms any traditional bicycle into a high-performance electric bike. Ideal for urban cyclists, bike commuters and light touring enthusiasts, it offers natural and quiet assistance (less than 55 dB) thanks to its integrated 25A FOC (Field Oriented Controller) controller. Compatible with 90% of bikes on the market, this Bafang central kit installs directly in place of the original crankset on standard JIS/BSA bottom bracket shells from 68 to 73 mm.

Technical architecture and motor

The Bafang BBS02 M315 is a geared mid-drive motor operating at 36V. It integrates a 25A controller with CAN Bus protocol, ensuring better stability, optimized communication with the display and battery, as well as increased reliability compared to older UART versions. The 1:21.9 reduction ratio and a motor speed of 120-126 RPM ensure efficient power transmission. The motor develops an effective torque of 100 N.m, more than sufficient for climbing urban hills and covering hybrid bike trails. Depending on the drivetrain configuration ("short transmission" as an option), the torque can even reach 120 N.m, surpassing the majority of 250W motors on the market. With efficiency exceeding 80% and a contained weight of 4.3 kg, the BBS02 combines power and lightness.

Compatibility and universal installation

• Bottom bracket: Standard JIS (Japanese Industrial Standard), compatible BSA, ISO/English, British, "square tapered spindle" or threaded. Spindle diameter of 33.5 mm, for bottom bracket shells from 68 to 73 mm (with spacers provided for 73 mm). Bottom bracket inner diameter: 33.6 to 36.0 mm. 100 mm and 120 mm versions are available for fatbikes and cargo bikes.
• Chainring: Default 44T or 46T. Available options: 36T, 48T, 52T. The 44T chainring offers the best torque (ideal for hills), the 46T/48T a good all-around compromise, the 52T maximum speed. Compatible with drivetrains up to 9 speeds maximum; beyond that, derailment risks may occur due to chainline offset.
• Wheel size: From 20 to 29 inches, adjustable via the LCD display.
• Bike types: MTB, hybrid bikes, city bikes, road bikes, light cargo bikes, compatible folding bikes. Compatible with most frames without modification.

Features and assistance modes

• Pedal sensor: Cadence sensor (speed sensor), detects pedaling motion to trigger assistance. Number of assistance levels adjustable via the display (typically 0 to 9).
• Throttle: Thumb throttle included, allowing full-electric mode without pedaling.
• E-Brake (motor braking): Connectors for brake sensors (mechanical levers or hydraulic magnetic sensors), instantly cutting assistance when braking.
• Gear sensor: Dedicated connector to momentarily cut assistance during gear changes, preserving the drivetrain.
• Maximum speed: Limited to 32 km/h (configurable), but can reach 45 km/h on 27.5 bikes