BLDC Motors for E-Bikes & Electric Scooters: Complete OEM Guide
The global e-bike market surpassed $45 billion in 2026, and at the heart of every e-bike is a BLDC motor that determines range, hill-climbing ability, noise level, and reliability. Whether you are building a fleet of rental scooters, a premium commuter e-bike brand, or an OEM assembly line, the motor choice defines your product. This guide covers hub vs mid-drive selection, power ratings, voltage systems, waterproofing requirements, EU certification, and what to ask your motor supplier before placing an order.
1. Hub Motor vs Mid-Drive: Which Architecture?
The fundamental decision for any e-bike OEM is motor placement. Each architecture has distinct implications for chassis design, gearing, and ride feel.
| Factor | Hub Motor (Rear/Front) | Mid-Drive Motor |
|---|---|---|
| Placement | Inside wheel hub | Bottom bracket (crank area) |
| Power range | 250W–2000W (rear), 250W–500W (front) | 250W–1000W (legal), 3000W+ (off-road) |
| Torque delivery | Direct to wheel — no drivetrain loss | Through chain/belt — leverages gears |
| Hill climbing | Struggles above 15% grade without gearing | Excellent — uses bike's gear range |
| Efficiency | 85–90% at cruise speed | 75–85% (drivetrain loss: 5–10%) |
| Weight | 2.5–5 kg | 3–4.5 kg |
| Noise | Near-silent (direct drive) or low hum (geared) | Audible whine at high RPM under load |
| Maintenance | Minimal — sealed unit | Moderate — chain/belt wear, gear oil |
| Rear flat tire repair | More complex — motor removal required | Standard bicycle procedure |
| Unit cost (250W) | $35–80 FOB | $80–200 FOB |
Our recommendation for OEMs: For commuter e-bikes at competitive price points, a geared rear hub motor (250W–500W) delivers the best cost-performance ratio. For premium mountain/trekking e-bikes targeting European markets, mid-drive provides superior hill performance and natural ride feel. For rental scooter fleets, a 350W–500W front or rear hub motor offers the lowest total cost of ownership and easiest field service.
2. Power Selection: 250W to 3000W
| Power | Application | Typical Speed | Regulatory Note |
|---|---|---|---|
| 250W | EU-legal commuter e-bike | 25 km/h (pedal-assist) | EN15194 compliant (EU) |
| 350W | US commuter e-bike, rental scooter | 32 km/h (Class 3) | Most US states allow |
| 500W | Cargo e-bike, fat-tire bike | 35–40 km/h | Check local Class 3 limits |
| 750W | High-power commuter, light off-road | 45 km/h | US Class 3 legal; EU requires type approval |
| 1000W | Off-road, utility, heavy cargo | 50+ km/h | Off-road only in most markets |
| 2000–3000W | Performance e-motorcycle, delivery trike | 60–80 km/h | Requires motorcycle registration |
3. Voltage System Selection
The battery voltage determines motor RPM range, system efficiency, and wiring cost:
- 36V: Standard for 250W EU e-bikes. Lower voltage = thicker cables for same power. Adequate for flat urban riding. Battery cost ~$150–250 for 10Ah pack.
- 48V: The global sweet spot. Supports 250W–1000W motors with good efficiency. Lower current for same power vs 36V means less I²R loss in cables and windings. Battery cost ~$200–350 for 14Ah pack.
- 60V: Common for 1000W–2000W scooters in Asian and LATAM markets. Requires 16S Li-ion configuration. Higher voltage = more cells in series = higher pack cost.
- 72V: Performance segment — 2000W+ e-motorcycles and heavy cargo trikes. 20S battery configuration. High voltage reduces current draw (P = V × I), enabling thinner gauge wiring and lower connector temperatures.
For OEMs: Standardize on 48V if you build multiple models — it covers the widest power range (250W–1000W) with the best supply chain availability for controllers, BMS, and chargers.
4. Waterproofing: IP65 as Baseline
E-bikes and scooters are outdoor products. Rain, puddle splash, and morning dew are inevitable. Motor IP rating directly affects warranty claims:
- IP54: Dust-protected + splash-resistant. Acceptable for fair-weather commuter bikes in dry climates. Not recommended as a product specification.
- IP65: Dust-tight + protected against water jets from any direction. This should be your minimum spec for any production e-bike or scooter motor. All Shenghe e-bike motors meet IP65.
- IP67: Dust-tight + immersion up to 1m for 30 minutes. Required for off-road and all-weather delivery vehicles. Adds 10–15% to motor cost due to additional sealing and corrosion-resistant bearings.
5. EU Certification: EN15194
If you sell into Europe, EN15194 (EPAC standard) is mandatory. It covers electrical safety, electromagnetic compatibility (EMC), and mechanical safety of electrically power-assisted cycles. Key requirements:
- Motor assist cuts off at 25 km/h (with ±10% tolerance)
- Continuous rated power ≤250W
- Motor must only provide assist while pedaling (pedelec) — throttle-only up to 6 km/h walk-assist is allowed
- EMC testing per EN 55014-1 and EN 61000-6-3
- Battery must meet EN 50604-1 (formerly EN 62133) for lithium cells
Shenghe e-bike motors are supplied with EN15194 compliance documentation. Our motors can be configured with the 25 km/h electronic speed limit and pedal-assist signal interface to meet Type 1 pedelec requirements.
6. Shenghe Motor E-Bike OEM Supply
- Rear hub motors: 250W, 350W, 500W, 750W, 1000W — 36V/48V
- Mid-drive motors: 250W, 500W, 750W — 36V/48V with torque sensor option
- All motors: IP65 dust-tight + water-jet protected as standard
- EN15194 compliance documentation provided
- Custom winding, axle length, flange, connector, and cable exit available
- MOQ 50 pcs standard; 200 pcs for custom variants
- Factory video audit and sample motor available on request