DM03: The Intelligent Mid-Drive.

Seamless Human-Machine Integration with 90Nm of Silent Torque.

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Key Performance Metrics

250W-350W

rated power

90N.m

max torque

3.5 KG

Motor Weight

IP65

WATERPROOF RATING

Technical Specifications

Rated Power

250W - 350W

Voltage Options

36V / 48V

Max Speed

140 RPM

Protection

IP65 Waterproof

Working Temp

-20 to 60C

Axle Type

Square (DM03) or Spline (DM03H)

Engineering Highlights

Vector Logic

Harnessing an advanced internal controller, the DM03 ensures exceptionally low noise operation and rapid, precise response to your pedaling input, creating a seamless and efficient ride.

Bilateral Sensing

Equipped with a sophisticated bilateral torque sensor, the system intelligently adapts to your pedaling effort, delivering power smoothly and instinctively for a truly natural riding feel.

Compact Design

Designed with a low-profile, side-access build, the DM03 offers unparalleled integration flexibility, fitting seamlessly into a wide range of custom bicycle frames without compromising aesthetics or ground clearance.

Experience the perfect synchronization between rider and machine. The DM03 uses bilateral torque sensing to mirror your pedaling effort, delivering 90Nm of power exactly when you need it—silently and efficiently.

Technical Specifications (DM03 Series)

Performance

  • Rated Power: 250W – 350W [cite: 88]
  • Max Torque: 90Nm [cite: 88]
  • Max Speed: 140RPM [cite: 88]
  • Voltage Options: 36V / 48V [cite: 88]
  • Reduction Ratio: 42.7 [cite: 85, 88]
  • Efficiency: High-speed (>6000 RPM internal) [cite: 84]

Engineering

  • Weight: 3.5kg [cite: 88]
  • Waterproof: IP65 [cite: 88]
  • Sensor: Bilateral Torque Sensing [cite: 87]
  • Axle Type: Square (DM03) / Spline (DM03H) [cite: 82, 88]
  • Chainring Support: 38T – 54T [cite: 88]
  • Controller: Vector Control (Low Noise) [cite: 88]
Product Identification System

Code Breakdown: [cite: 88]
• 03: DM03 Series
• A / H: Square Axle / Spline Axle
• 035: Power Rating (035 x 10 = 350W)
• 239: Production Date (e.g., Sept 2023)
• 00001: Sequential Serial Number

What’s in the Box

Component Specification Qty
Drive Unit DM03 / DM03H Series 1
Chainring Standard 42T (38-54T optional) 1
Left & Right Cranks 170mm 1 Pair
Locknut M42 x 1.5 1
Axle Screw M8 x 1 x 15 2

Optional Accessories & Material Specs

  • Mounting Rack: Aluminum AL6061T6
  • Decorative Piece: High-Grade ABS
  • Right Cover: High-Grade ABS
  • Speed Sensors: Model SVS1 / SVS2

Comprehensive Installation Guide

Please read every step carefully. Incorrect installation can result in permanent damage to the motor or your bicycle frame.

Step 0: Preparation & Tools

Before you begin, ensure you have the following tools ready:

  • Special Toseven Wrench (Included)
  • 8mm Allen Wrench (for Motor & Cranks)
  • 4mm Allen Wrench (for Sensor)
  • 3mm Phillips Screwdriver (for Covers)
  • Slotted Screwdriver (for Magnets)
  • Scissors (for Cable Ties)

1. Mounting the Drive Unit

Position the motor unit so the arrow on the casing points directly toward your mounting bracket. Align the three M8 threaded holes on the motor with the three clearance holes on the bracket.

  • Insert the motor into the bracket until it is fully seated.
  • Fasten using the three provided M8x35 screws.
  • Torque: Tighten these screws firmly to 15 Nm.

2. Decorative Guards & Right Cover

Install the protective covers to prevent debris from entering the motor assembly:

  • Right Cover: Secure using two M3x20 screws.
  • Decorative Cover: Affix using two M3x25 screws.

3. Chainring Mounting (CRITICAL)

This step requires the Special Wrench included in your kit.

  • Align Splines: Carefully line up the internal teeth of the chainring with the external splines on the motor axle.
  • Press Fit: Firmly press the chainring on by hand until it is completely flat against the base.
  • Lock Nut: Using the special wrench, tighten the lock nut in a COUNTER-CLOCKWISE direction.
  • Torque: Tighten to 15 Nm.

4. Crank Arms Installation

Slide the 170mm left and right cranks onto the axle. Tighten the bottom bracket screws (M8x1x15) using your 8mm Allen wrench.

Safety Torque: Tighten these to 35-40 Nm. If these are loose, the cranks can fall off during a ride. Check these after your first 50 miles.

5. Speed Sensor & Magnet Calibration

  • Sensor: Secure the sensor to the bicycle fork using two cable ties.
  • Magnet: Attach the magnet to a wheel spoke using a slotted screwdriver. The flat surface must align with the circular mark on the sensor.
  • Model SVS1 Adjustment: Loosen the sensor screws and move it to achieve a distance of 2-5mm between the sensor mark and the magnet.
  • Model SVS2: This model is fixed; ensure the distance remains within 15mm for proper function.

Model: SVS1

Model: SVS2

6. Final Wiring & Cable Management

Connect the E-Bus cable, Battery, and Speed Sensor to the matching motor connectors. The other ends of the E-Bus cable connect to your display, throttle, and brakes.

⚠️ CRITICAL CABLE ROUTING:
Do NOT route cables through the narrow space between the motor and the frame. This will pinch and sever the wires as the motor moves under load. Always route cables along the exterior of the frame tubes.

Wiring & Speed Sensors

Speed Sensor Models

SVS1 (Adjustable)

Achieve 2-5mm distance between sensor mark and magnet.

SVS2 (Fixed)

Proper function maintained within 15mm max distance.

⚠️ Cable Routing: Avoid narrow spaces between motor and frame to prevent pinched wires.

Use & Storage Conditions

Regular Operation

  • Temperature: -20℃ to 50℃
  • Relative Humidity: ≤ 95%
  • Atmospheric Pressure: 86KPa – 106KPa

Storage Environment

  • Temperature: 0℃ to 35℃ (32°F to 95°F)
  • Relative Humidity: ≤ 85%
  • Cleanliness: Clean and well-ventilated space

Note: For optimal performance and longevity, ensure the storage area is free of corrosive gases.