High Torque Motor QSJ128B-70 is a high-performance 72V permanent magnet synchronous mid-drive gear motor, specially designed for high-speed electric motorcycles, off-road e-bikes and heavy-load electric vehicle conversion kits.
Combining outstanding torque output, high efficiency and all-weather IP67 protection, this motor delivers stable powerful performance under steep climbing, frequent acceleration and long-time heavy-duty operation.
Core Advantages
Industry-Leading Peak Torque 67N·m
The raw maximum torque reaches 67N·m before deceleration. Matched with a 3.462 reduction gear set, it generates explosive climbing force, easily coping with steep slopes, heavy cargo and off-road rough terrain.
S9 duty cycle supports repeated acceleration and hill climbing without obvious thermal attenuation.
Ultra-High Energy Efficiency
The motor achieves over 95% peak efficiency, cutting power consumption effectively. With the optimized PMSM structure, it extends your riding range under the same battery capacity and reduces long-distance driving costs.
Stable & Safe High-Temperature Performance
Class F high-temperature resistant windings and Class H full-machine insulation allow continuous heavy-load operation. The optional KTY83-122 thermistor monitors internal temperature in real time to prevent overheating damage. Thick 12mm² phase wires eliminate overheating risks under large current output.
All-Weather IP67 Waterproof & Dustproof
IP67 ingress protection enables reliable riding in rainy, muddy and shallow wading environments, widely adaptable to outdoor cross-country and daily commuting scenarios.
Precise & Smooth Power Output
Equipped with an encoder position sensor, the motor provides linear, jitter-free power delivery at low and high speeds, bringing comfortable and controllable riding experience.
Wide Compatibility
Standard 72V voltage platform fits most mainstream lithium battery packs. It matches controllers with 160A bus limit and 520A peak phase current, ideal for high-power e-bike refit projects. Natural cooling design requires no extra cooling accessories and lowers maintenance costs.
Application Scenarios
· High-speed electric motorcycle conversion kits
· Off-road & mountain electric bikes
· Heavy-load cargo electric two-wheelers
· Custom high-power EV modification projects
